Integrated reduced-exposure x-ray fluoroscopy device

Abstract

To address such a problem that conventional medical C-arm angiography systems have difficulty to provide radiation protection through devices thereof, in the past, protective devices have been proposed in which an FPD and an X-ray source are separated above and below a table and the FPD is stored within a box with a shielding ability, however, there is no X-ray source applicable to the FPD that moves significantly within the box.SOLUTION: An X-ray source with four or more motion axes (two axes are rotation axes) is devised. The X-ray source and a Y-axis rail 105 thereof can be stored under a table 2. When an X-axis rail 104 and the Y-axis rail of the X-ray source are formed to have an elliptic arc path, etc., the irradiation angle can be increased and the operation area becomes smaller. Further, when a basic coordinate system and a reference point thereof are provided, both the FPD 40 and a synchronous X-ray source 100 can share mutual position and orientation information to be able to determine the position and orientation. The FPD storage box 18 and the present invention can reduce the radiation exposure of medical personnel and patients, as well as reducing the burden of protecting medical personnel.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention provides an X-ray fluoroscopy device for medical use that has an under-tube type box with shielding function. The device is installed separately with an X-ray receiver on the table and an X-ray source below the table, both of which have a large range of motion in both the XY axes and rotational directions (hereinafter referred to as "large range of motion"), thereby providing an X-ray fluoroscopy device that can obtain a large field of view (hereinafter referred to as "large range of motion field") and a large irradiation angle due to the large range of motion. [Background technology]

[0002] The use of radiation in the medical field is becoming increasingly widespread. A typical example is treatment using interventional radiology (IVR). In IVR, thin tubes and needles called catheters are inserted into the body while viewing X-ray fluoroscopy images and angiograms. This allows for treatment of illnesses without surgery and with as little scarring as possible.

[0003] Today, specialists in various medical fields (hereinafter referred to as "operators") use X-ray (hereinafter referred to as "X-ray") fluoroscopy systems to perform numerous surgeries as part of clinical procedures. The use of radiation in medical treatments is steadily increasing, and procedures involving radiation exposure for patients and medical personnel are becoming more common. However, when primary X-rays from an X-ray source are irradiated onto the affected area, scattered X-rays are emitted in all directions from the patient's body, exposing medical personnel to radiation. With the increased use of X-rays, the duration of exposure to X-rays tends to be longer, resulting in increased medical exposure for patients and occupational exposure for medical personnel. Furthermore, in some cases, radiation protection measures are lagging behind, increasing the risk of radiation damage for medical personnel and patients.

[0004] Angiography uses an X-ray fluoroscopy system (hereafter referred to as "angiography system"). Angiography is a method of observing the shape of the blood vessels themselves by injecting a contrast agent into the blood vessels and capturing its flow with X-rays. By injecting a contrast agent that is difficult for X-rays to pass through into the target blood vessel and then taking X-rays, the shape of the blood vessels in the area where the contrast agent has entered can be clearly visualized. In addition, the angiography system is constantly performing fluoroscopy or observation during surgery. Therefore, medical procedures using an angiography system expose medical staff and patients to high radiation doses. Some recent angiography systems emit pulsed X-rays to reduce medical exposure and occupational exposure of medical staff.

[0005] Here, we will use an angiography system as a representative example to explain its structure, usage, and the behavior of X-rays. A typical angiography system has an X-ray tube installed either above or below the table on which the patient lies. Additionally, an X-ray receiver installed in the opposite direction receives the X-rays that pass through the patient. In an angiography system, the direct X-rays inherently emanate in a straight, unidirectional path, emanating from the X-ray tube in the X-ray source, passing through the patient, and arriving at the receiver. A small portion of the X-rays emitted from the X-ray tube and passing through the patient enter the receiver. A portion of the incident X-rays is transmitted as fluoroscopic image data and displayed on an LCD TV screen. However, most of the X-rays are scattered by the patient's body and emitted as scattered radiation around the system.

[0006] According to Non-Patent Document 1 (ICRP, 2017), from the perspective of radiation protection for medical professionals, the use of under-tube angiography systems, in which the X-ray source is placed below the table, is recommended for interventional radiology procedures. In this angiography system, the primary X-rays from the X-ray tube and their small-angle scattered X-rays travel upward. However, scattered X-rays caused by the table and patient's body travel not only upward, but also to the sides and downward. Non-Patent Document 1 also states that the number of photons of scattered X-rays in an under-tube system is greatest below the table. Patent Document 1 states that for under-tube type primary X-rays of about 100 KeV, for example, the scattering and absorption ratios are as follows: Approximately 80% is scattered by body tissue, and over 10% is absorbed. Most is scattered by the table, and about 3% is absorbed. As a result, about 3% is transmitted to the X-ray receiver.

[0007] Non-Patent Document 1 (ICRP, 2017) proposes the use of protective equipment to protect medical personnel and patients from radiation. This equipment includes lead aprons, eye protection (protective glasses), and thyroid protection for individuals. For multiple personnel, protective curtains, ceiling-mounted shields, and on-board shields are also available. However, these radiation protection devices are designed to protect only against X-rays traveling in a specific direction, i.e., X-rays from the intended direction. Therefore, the effectiveness of these devices in reducing radiation exposure is limited to a specific direction. Therefore, the purpose of these devices is to at least partially reduce radiation exposure for medical personnel who move around during surgery. However, these devices do not provide a fundamental solution to reducing radiation exposure from scattered X-rays from all directions.

[0008] In particular, in recent years, legal restrictions on crystalline lens dose have been imposed to reduce exposure to the surgeon's eyes. Accordingly, an increasing number of interventional radiologists are wearing crystalline lens dosimeters in addition to protective glasses. However, small-angle scattered X-rays from the periphery of the radiation field in under-tube scanners have high energy and are as intense as primary X-rays. These forward scattered X-rays irradiate the surgeon's eyes. Therefore, current lead glasses and goggles do not provide sufficient shielding at the bottom and sides of the glasses. However, protective glasses must be lightweight to reduce physical strain. Therefore, there is a certain limit to how much the surgeon's crystalline lens dose can be reduced.

[0009] As mentioned above, scattered X-rays come in three directions from the patient's body: forward, side, and back. These scattered X-rays are broadly divided into three types depending on the energy source and their effective energy. The highest energy types are small-angle scattered X-rays that are generated from the irradiation field and its surrounding area upward (to the front of the under-tube type). Small-angle scattered X-rays are included in forward scattered X-rays. The next highest energy types are scattered X-rays that are generated from areas close to the irradiation field in three directions: forward, side, and back (hereinafter referred to as "all directions"). The lowest energy types are scattered X-rays that are generated from the entire patient's body within 40 cm of the irradiation field and are re-scattered several times by human tissue (hereinafter referred to as "scattered X-rays from the whole body").

[0010] Patent Document 1 relates to a composite absorbing material for scattered X-rays, invented by the same inventor. Patent Document 1 proposes a composite absorbing material that attenuates and absorbs scattered X-rays by using a multilayer structure consisting of three or more closely stacked layers with different functions. Note that Patent Document 1 is a materials patent.

[0011] Patent Document 2 relates to a medical table (hereinafter referred to as the "high-performance table") invented by the same inventor that allows good transmission of X-rays and reduces scattered X-rays. The high-performance table uses a mesh or thin CFRP sheet near the irradiation field to reduce scattering and absorption, allowing good transmission of primary X-rays. The high-performance table also reduces the intensity of scattered X-rays generated by the patient's body and directed downward. As a result, the high-performance table allows good transmission of primary X-rays and can reduce the radiation exposure of medical staff and patients.

[0012] Patent Document 3 relates to an additional shielding box devised by the same inventor to reduce radiation exposure and the protective load. The additional shielding box is assembled and installed on a table, surrounding the radiation field of the patient's trunk, etc. This reduces the intensity of scattered X-rays traveling upward and to the sides. The additional shielding box is composed of a box body, a box top plate, a viewing window, a patient port, a shielding sheet for the left side of the box, a sleeve port, and a sleeve structure for the left side of the box. During surgery, medical personnel can see inside the box through the viewing window, which has shielding capabilities, on the side wall of the box. At the same time, during surgery, medical procedures are performed by inserting their arms through the sleeve structure attached to the sleeve port on the side wall of the box. The viewing window and sleeve structure have shielding capabilities. The sleeve structure is a sleeve, glove, or gloveless port. As a result, the additional shielding box can reduce the radiation exposure dose of medical staff and patients, and reduce the air dose rate in examination rooms, etc.

[0013] One type of additional shielding box described in Patent Document 3 is a C-arm type additional shielding box (hereinafter referred to as a "C-arm type box"), which houses the X-ray receiver of a C-shaped arm (hereinafter referred to as a "C-arm") that is widely used in recent angiography devices, sandwiched between two split boxes. The C-arm of an angiography device with a C-arm (hereinafter referred to as a "C-arm type angiography") has an X-ray source and an X-ray receiver located at opposite ends of the arm, and the positions of the X-ray source and the X-ray receiver are fixed and can be swung while remaining facing each other. In the C-arm type box, the X-ray receiver inside the box can be swung 15 to 30 degrees in both the X-axis and Y-axis directions (hereinafter referred to as "XY axis / rotational directions").

[0014] Another type of additional shielding box described in Patent Document 3 is an additional shielding box with a built-in flat panel detector (FPD) (hereinafter referred to as an "FPD-integrated box"). In an FPD-integrated box, the FPD itself, which is an X-ray receiver, is installed inside the box. The FPD, which is the X-ray receiver inside the box, can be swung over a wide range, either manually or mechanically. This corresponds to the 45-degree swing of a C-arm angiography device. Meanwhile, Patent Document 3 describes a case in which an independent, commercially available portable X-ray source is installed on the floor below the table. However, Patent Document 3 does not describe a method for autonomously determining the position and orientation of the X-ray source in synchronization with the position and orientation of the X-ray receiver (FPD).

[0015] Patent Document 4 relates to a combined protective device / instrument / instrument (PDITS) that combines a protective device (PD) consisting of a box and table, and a protective device (PI) consisting of a blanket, clothing, additional protective equipment, etc. In principle, it is impossible to block all the scattered X-rays generated from the patient's body with just one of these protective devices. Therefore, the PD and PI are combined. The table reduces the scattered X-rays generated from the patient's body downward, while the box reduces them upward and to the sides.

[0016] The box in Patent Document 4 is a rectangular box that is placed on a table and has functional materials placed on the surface or inside where scattered X-rays are incident. An X-ray receiver is placed inside the box. The functional materials refer to shielding materials or composite absorbing materials. On the other hand, the additional shielding box is an internal component of the box, and is positioned as a box with many advanced functions that add the functions of devices for visualizing the interior and devices for operating the interior, reducing the radiation exposure and protective burden of medical personnel. The table in Patent Document 4 is a flat table with a functional material on its top surface that has the ability to shield against scattered X-rays from a patient placed on it. On the other hand, the high-performance table is included in the table category and is positioned as a table with advanced functions such as increasing the transmittance of primary X-rays and reducing scattered X-rays. Incidentally, Patent Document 4 does not describe the structure or operation method of an X-ray detector (FPD) or X-ray source with a large movable range.

[0017] The background art of Patent Document 1 describes the results of a survey of the structure and materials of prior art protective equipment. It states that there are no other protective equipment materials equivalent to this invention. In other words, there is no material that attenuates and absorbs scattered X-rays using a multi-layer structure of three or more layers, in which a low-reflection attenuation layer and a multi-layer absorbing layer are closely stacked and the outermost layer is an electronic absorber. Therefore, there is no material similar to the composite absorbing material of Patent Document 1. Note that Patent Document 1 is a materials patent and does not claim protective equipment or its structure. The background art of Patent Document 2 describes the results of a survey of the structures and materials of prior art tables and their accessories. These tables do not have mechanisms for transmitting X-rays in the irradiation field or diaphragm mechanisms. Furthermore, these tables do not have the function of attenuating and absorbing scattered X-rays with the material of the tabletop. Therefore, there are no tables similar to the high-performance table in Patent Document 2. The background art section of Patent Document 3 describes the results of a survey of prior art human body protection devices, radiation shielding devices, and radiation protection cabins. These devices all lack a mechanism for protecting the surgeon's hands and arms. Furthermore, these devices lack a rectangular box that surrounds the radiation field in three dimensions. Furthermore, these devices lack the function of attenuating and absorbing scattered X-rays using the material of the box. Furthermore, the radiation shielding device does not provide lateral shielding for the patient's body in the direction of their height (hereinafter referred to as the "body axis direction"). The radiation protection cabin does not provide shielding above the table. In other words, nothing similar to the additional shielding box described in Patent Document 3 was found. In the background art of Patent Document 4, it is stated that Patent Document 4 is a combination and further development of Patent Documents 1 to 3, but that there is no prior art similar to the inventions in Patent Documents 1 to 3. In other words, there is no prior art similar to Patent Document 4. The present invention is an improvement over the concepts and structures of Patent Documents 3 and 4, and further develops the concepts and structures of the X-ray receiver and X-ray source, as well as the structure and operation method of the position and attitude determination mechanism. There was no prior art similar to the inventions of Patent Documents 1 to 4. Therefore, the content of the present invention does not exist in those prior arts.

[0018] Patent Document 5 is a US patent and relates to a radiation irradiation area division device. The device in Patent Document 5 is a medical X-ray irradiation device in which a patient on a table, an X-ray source unit, and a camera unit are surrounded by a radiation shield, and the X-ray source unit and camera unit are supported by a movably supporting structure, and the radiation shield has a bellows structure so that it can accommodate the movement required for irradiation. The device in Patent Document 5 is an X-ray shielding device, and has a frame whose lower surface is supported by the floor and whose upper end supports the table. The table has a head section, legs, and top section, and the patient is placed on the top section. The frame and table are connected. The X-ray device has a base section, to which are connected a vertical section, horizontal section, and connecting structure. The connecting structure is attached to the vertical section and connected to the support beam. The beam is rotatable, supported by the horizontal section, and driven by a motor. The support beam rotatably supports a pin-structured connecting section, to which an arm is attached and a rotatable connecting section is located at the edge of the arm. The arm is rotatably connected here, and there is a yoke structure at the tip. The upper yoke structure carries the camera (X-ray receiver), and the lower yoke structure carries the X-ray source, both of which are supported by the pin support structure, and both are directed towards the patient's irradiation area. An upper shielding structure is connected to the camera section. The upper shielding structure has a bellows structure that allows the camera to move from the middle, and is connected to the part surrounding the patient. A lower shielding structure is connected to the X-ray source, which has a bellows structure midway through to allow the X-ray source to move, and is connected to the underside of the table that supports the patient. The yoke is a soft iron that amplifies the magnetic attraction of the magnet and exists to form a magnetic circuit. The present invention does not have a bellows-type lower shielding structure or upper shielding structure. Furthermore, the X-ray source and X-ray receiver are supported by a yoke-type pin support structure. While a rotation mechanism appears to exist, there is no mention of a mechanism for moving in the XY directions. It is unlikely that the overall position and orientation of the X-ray source and X-ray receiver can be freely determined. Furthermore, the device in Patent Document 5 does not have a rectangular box that three-dimensionally surrounds the irradiation field, and the X-ray receiver is not installed within the box. In other words, the configuration of the device in Patent Document 5 differs from that of the present invention.

[0019] As described above, the present invention relates to the structure of the X-ray receiver in the box and the X-ray source under the table, as well as the structure and operation method of the position and attitude determination mechanism, which is a further development of the protective devices of the inventions in Patent Documents 1 to 4. There was no prior art similar to the inventions in Patent Documents 1 to 4. In addition, in U.S. Patent Document 5, the X-ray receiver in the box is installed in an upper shielding structure with a bellows structure. The X-ray source is installed in a lower shielding structure with a bellows structure and is supported by a pin support structure with a yoke structure. The configuration of Patent Document 5 differs from the present invention, in which the X-ray receiver is installed in a box. Therefore, Patent Document 5 is not prior art of the present invention. Therefore, there is no prior art that corresponds to the present invention. Also, currently, there is no X-ray source that is stored under the table and has four or more motion axes and rails with long path lengths in both the X and Y directions. [Prior art documents] [Non-patent literature]

[0020] [Non-Patent Document 1] ICRP Recommendations Translation Review Committee, ICRP Publication 117, "Radiation Protection in Fluoroscopically Guided Procedures Performed Outside Diagnostic Imaging Departments," Japan Radioisotope Association, March 31, 2017 [Non-patent document 2] Japan Radiological Medical Systems Industry Association QA Committee, "General Rules for Medical X-ray Equipment JIS Z 4701-1997 Guide," October 1998 [Patent documents]

[0021] [Patent Document 1] Patent Application No. 2022-161788 (domestic priority application, earlier application is Patent Application No. 2022-001336) [Patent Document 2] Patent Application No. 2022-123002 (domestic priority application, earlier application is Patent Application No. 2022-018334) [Patent Document 3] Japanese Patent Application No. 2023-174737 (divisional application of Patent Document 4, original application is Japanese Patent Application No. 2022-075633) [Patent Document 4] Patent Application No. 2022-205553 [Patent Document 5] US 1006325538 B Summary of the Invention [Problem to be solved by the invention]

[0022] In recent medical settings, the C-arm of angiography equipment is used with a large range of swing (hereinafter referred to as "large swing range") in the X-axis, Y-axis, and rotational directions of the C-arm (hereinafter referred to as "XY axes and rotational directions"). Because the X-ray detector (FPD) of this type of angiography equipment is exposed, it is difficult to provide shielding functionality within the equipment itself. For this reason, two types of protective equipment have been proposed in the past: one that separates the FPD and X-ray source above and below the table, and houses the FPD in a shielded box. One of them is the C-arm type additional shielding box (hereinafter referred to as "the box") disclosed in Patent Document 3. However, in this device, the X-ray receiver of the angiography device inserted into the box from the outside cannot be swung over a large range of movement in both the X and Y axes and in the rotational direction. Another example is a box with a built-in FPD, as described in Patent Document 3. In this device, the FPD, which is an X-ray receiver housed in the box, can be swung over a wide range of movement. However, this requires the use of a portable floor-mounted X-ray source or the like for the X-ray source below the table. Commercially available floor-mounted X-ray sources do not have the function to adjust the position and angle. At present, there are no X-ray sources that can be used with an FPD that moves widely within the box. In other words, with conventional devices that house an FPD in a box, it is not possible to swung the FPD over a wide range of movement to capture images of the affected area. Therefore, the conventional C-arm type box of Patent Document 3 cannot meet the needs of modern medical settings. Also, conventional FPD-integrated boxes do not have an available X-ray source. These details will be explained below.

[0023] X-ray fluoroscopy systems, such as angiography systems, are used for treatment under X-ray transmission. This article explains how the C-arm of a C-arm angiography system is used in modern medical settings. In modern medical settings, C-arms often require a wide range of movement in both the X- and Y-axes and in rotation. The C-arm performs examinations by changing the irradiation angle of the X-ray source and X-ray receiver to confirm the position of treatment instruments such as balloons after catheterization procedures. Conventionally, examinations are performed in the right anterior oblique (RAO), left anterior oblique (LAO), and craniocaudal (CRA) directions, each at an irradiation angle of 30 to 45 degrees from the vertical. It is desirable for the X-ray source and X-ray receiver (FPD) of future X-ray fluoroscopy systems to be able to oscillate even more widely in both the X- and Y-axes and in rotation (e.g., 45 degrees or more).

[0024] First, we will explain the conventional C-arm type additional shielding box. A C-arm type angiography system has an X-ray source and an X-ray receiver located at either end of a C-shaped arm (hereinafter referred to as "C-arm"), and the positions of the two are fixed so that they can swing while facing each other. In recent years, there have been many cases of C-arm type angiography systems being introduced. In Patent Document 3, the same inventor devised a C-arm type box into which an X-ray receiver is inserted as one type of additional shielding box. The C-arm type is assembled by sandwiching a receiver joint between the box body and the end box. A slide table, which allows the receiver port to move in the X-axis direction, is located on the ceiling of the end box, and the slide table itself can move in the Y-axis direction along guide rails using rollers (wheels). The receiver arm of the X-ray receiver is stored in the receiver port with a sliding guide wrapped around the outside. It is then sandwiched between the receiver joint attached to the box body and the end box. Bellows shielding is attached to the sliding surfaces of the end box, receiver joint, and slide table to shield the space created by the movement of the X-ray receiver. This eliminates openings through which scattered X-rays can leak. The inside of the ceiling surface of the end box, the receiver joint, and the slide table are coated with a ray attenuating material or a composite absorbing material. This allows the X-ray receiver to be housed in the end box and the box body (hereinafter referred to as the "box, etc.") and moved, the opening can be blocked for shielding, and scattered X-rays generated inside the box, etc. can be attenuated and absorbed. The above is within the scope of prior art. C-arm angiography systems that can be used in C-arm boxes are limited to those with small external dimensions for the X-ray receiver. While this depends on the dimensions of the X-ray receiver, such as the FPD system, installed, Patent Document 3 states that the X-ray receiver inside the box can oscillate 15 to 30 degrees in the X- and Y-axis directions. Meanwhile, as mentioned above, in medical settings, C-arm angiography systems are used with RAO, LAO, and CRA, each oscillating at an irradiation angle of 30 to 45 degrees from the vertical. Therefore, with the current oscillation range of the X-ray receiver inside a C-arm box, this system cannot meet the needs of medical settings.

[0025] Next, we will explain a conventional box with a built-in flat panel detector (FPD), which was invented by the same inventor in Patent Document 3. The FPD is a type of X-ray receiver. In this box, the FPD is housed inside the box along with all of the operating mechanisms. The FPD is an independent, stand-alone X-ray flat panel detector, and image information is retrieved via a wired or wireless LAN connection. Since there are no objects penetrating the ceiling of the end box, forward scattered X-rays can be reliably shielded by the end top panel. This improves the image resolution of the X-ray receiver, which in turn reduces the X-ray output of the X-ray source. In Patent Document 3, the FPD movement mechanism inside the box consists of a slide table in the X and Y axes, an extendable arm in the Z axis and one rotation axis, and an FPD attitude control plate in the tilt axis. These movement axes are five-axis. The extendable arm is attached to the moving plate of the slide table. The moving plate can move in the X axis along rails on both sides of the linear slide table. Meanwhile, the moving plate can move in the Y axis using roller mechanisms on both ends of the slide table. The movement mechanism can be manual or automated using mechanical power. The FPD movement mechanism inside the box can be adjusted to a position and orientation of RAO and LAO at 45 degrees from the vertical. In other words, the swing angle of the C-arm can be adjusted to more than 45 degrees from the vertical. Furthermore, since there is no C-arm or receiver arm, there is no equipment around the box that would interfere with surgery, allowing medical personnel to perform surgery easily in a spacious area. The above is within the scope of prior art.

[0026] Patent Document 3 describes a commercially available portable X-ray source with adjustable position and angle that is separately installed on the floor below. The portable X-ray source is said to be mounted on casters or other devices that can maintain its position and tilt angle. However, no commercially available floor-mounted external X-ray source with a function for determining its position and orientation (hereinafter referred to as "position and orientation determination function") has been found. Furthermore, boxes with built-in FPDs do not have a function for determining the position and orientation of the floor-mounted X-ray source. Therefore, Patent Document 3 states that the above-mentioned X-ray source has remaining issues to be considered, and that a separate solution will be devised. [Means for solving the problem]

[0027] This invention provides an X-ray fluoroscopy device with a medical under-tube type box with shielding function, in which the separately installed X-ray receiver and X-ray source have a wide range of motion in both the XY axes and rotational directions, and a wide irradiation angle can be obtained with a wide range of motion field.In the following, we will start by examining a conventional box with a built-in FPD. First, we propose a prototype device with an X-ray source stored under the table and equipped with a mechanism for moving in both the X- and Y-axes as well as in the rotational direction. Next, we propose an improved device that allows for an even larger range of motion. Finally, we propose an X-ray fluoroscopy device in which the X-ray source and X-ray receiver can share position and orientation information to determine their mutual position and orientation.

[0028] In an under-tube type X-ray fluoroscopy system, the X-ray source is placed under the table. The X-ray detector (FPD) is placed above the table. In a box with an integrated FPD, the FPD is stored inside the box. In conventional boxes with an integrated FPD, the FPD movement mechanism has five movement axes (three axes (X, Y, and Z), one rotational axis (Z), and one tilt axis) to determine its position in space.

[0029] First, we will explain the X-ray source, which is housed under the table and has mechanisms for movement in both the X and Y axes and in the rotational direction. In the case of the under-tube type, the X-ray source is installed under a table, etc. In this invention, an X-ray source that can freely change its own position and orientation based on instructed position and orientation information and can freely adjust the emission angle of the X-ray source is called a "synchronous X-ray source."

[0030] The motion mechanism of the synchronous X-ray source has two axes: the X- and Y-axis directions of the X-ray source slide table, and the pan and tilt axes of the X-ray source two-axis attitude control plate. In other words, the synchronous X-ray source has a total of four motion axes. With four motion axes, it is possible to determine the position and orientation to a certain extent in the space below the table. Therefore, four or more motion axes are a necessary condition.

[0031] The synchronous X-ray source is installed on an X-ray source support stand fixed to a sturdy FPD storage box stand. The X-ray source support stand is installed in an upper space slightly away from the floor of an examination room, etc. An X-ray source slide table is installed on the X-ray source support stand. By operating this, the position of the synchronous X-ray source on the X-axis and Y-axis can be determined. An X-ray source two-axis attitude control plate is installed on the X-ray source slide table. The synchronous X-ray source is installed on the X-ray source two-axis attitude control plate. The X-ray source two-axis attitude control plate can determine its attitude on two axes: the horizontal pan axis and the up-down tilt axis. This operating mechanism allows the X-ray source to move in the X and Y directions within the range of the X-ray source slide table, and the irradiation angle can be adjusted to approximately 120 degrees, from 0 to 360 degrees horizontally along the pan axis and from -60 to +60 degrees up or down from the vertical along the tilt axis.

[0032] In the prototype device, both the Y-axis rail and the X-axis rail of the X-ray source slide table are linear. The Y-axis rail is generally located under the table. The Y-axis rail is fixed to the X-ray source support stand. The X-axis rail rests on the Y-axis rail and initially protrudes to the left of the table. For right anterior oblique (RAO) imaging, the X-axis rail remains positioned overhanging the left side of the table, but for left anterior oblique (LAO) imaging, the X-axis rail is moved to the right side of the table by the X-axis feed mechanism.

[0033] Through drawing studies, we evaluated the relationship between the operating dimensions (area) and irradiation angle of the prototype device. Note that the operating dimensions (area) refer to the dimensions (area) required for the device to operate. The Y-axis rail has a linear length and path length of 140 cm to fit in the space below the table. The FPD housed in the box has a range of motion in the Y-axis direction of 65 cm. This results in an irradiation angle of the synchronous X-ray source in the Y-axis direction of 45 degrees from the vertical. The X-axis rail extends approximately 60 cm on one side of the table. During medical procedures, it is desirable for the rail to extend only on one side of the table (either the left or right side). In this case, the length of the rail in a linear configuration is approximately 120 cm. The linear path length corresponding to both sides of the table is 170 cm. The operating range of the FPD in the X-axis direction housed in the box is 40 cm. This results in an irradiation angle of the synchronous X-ray source in the X-axis direction of 60 degrees from the vertical. For details of the drawing study, please refer to Examples 4 to 7 described below.

[0034] To summarize the relationship between the operating dimensions and irradiation angle in the prototype device described above, the X-ray source operating mechanism has rails that provide a path length more than twice the movable range of the X-ray receiver in both the X and Y axis directions, so the irradiation angle of the X-ray source that can be received by the X-ray receiver is more than 45 degrees from the vertical. Both the synchronous X-ray source and the X-ray receiver have four or more axes of motion. The pan and tilt axes of the synchronous X-ray source and the rotation axis of the X-ray receiver's Z-axis rotation mechanism have a range of motion of 120 degrees or more. The inter-surface distance (hereafter referred to as "inter-surface distance") from the center position of the synchronous X-ray source tilt axis to the image receiving surface is approximately 50 cm. The inter-surface distance varies from 45 cm to 55 cm depending on the tilt angle of the FPD, but the difference is not significant.

[0035] The irradiation angle of the prototype device is 45 degrees from the vertical in the Y-axis direction and 60 degrees from the vertical in the X-axis direction. The Y-axis direction is equivalent to that of a conventional C-arm angiography device. In the X-axis direction, an irradiation angle equivalent to or slightly larger than that of a C-arm angiography device can be obtained. Furthermore, since there is no C-arm or its drive unit extending from the table, the operating dimensions (area) are smaller than those of a C-arm angiography device. For details of the prototype device, please refer to Examples 1 and 2 described below.

[0036] Next, we propose an improved device that allows for an even greater range of motion. In the improved device, the Y-axis of the X-ray source slide table has an elliptical rail path, and the X-axis rail has a circular path. The Y-axis rail is generally housed and fixed under the table, and the length of its elliptical path is longer than that of the original device. The circular path X-axis rail extends to the left of the table in the initial state, and in this state, RAO imaging is possible. LAO imaging can be performed by moving the X-axis rail to the right of the table using the X-axis feed mechanism. Other configurations are the same as the prototype device. For details of the improved device, see Example 7 below.

[0037] Using a similar drawing study, we evaluated the relationship between the operating dimensions and irradiation angle of the improved device. The Y-axis rail of the elliptical arc path is stored under the table, so the length of the elliptical arc path is 165 cm. The operating range of the FPD in the Y-axis direction is 65 cm. This results in an irradiation angle of the synchronous X-ray source in the Y-axis direction of 60 degrees from the vertical. One of the X-axis rails of the arcuate path extends approximately 35 cm to one side of the table. Because of its arcuate shape, the extension dimension is smaller than that of a linear path. The length of the arcuate path on both sides of the table, which defines the working dimension, is 170 cm. The X-axis operating range of the FPD housed in the box is 40 cm. This results in an X-axis irradiation angle of the synchronous X-ray source of 60 degrees from the vertical. If a Z-axis tilt axis is added to the FPD operating mechanism, for a total of six axes of operation, the X-axis irradiation angle can be increased to approximately 90 degrees. For details of the drawing study, see Examples 3 to 6 described below.

[0038] To summarize the relationship between the operating dimensions and irradiation angle in the improved device mentioned above, just like the original device, the X-ray source operating mechanism has rails that provide a path length in both the X and Y axis directions that is more than twice the movable range of the X-ray receiver, making the irradiation angle of the X-ray source that can be received by the X-ray receiver 60 degrees or more. The Y-axis irradiation angle was more than 45 degrees from the vertical in the original device, but it is now more than 60 degrees in the improved device. Also, the operating dimensions on the X-axis side are reduced by 50 cm in total on both sides.

[0039] The improved device's irradiation angle is 60 degrees from the vertical in the Y-axis direction, and more than 60 degrees from the vertical in the X-axis direction. Compared to conventional C-arm angiography systems and the prototype system, the improved device can achieve larger irradiation angles in both the X and Y-axis directions. In addition, the operating dimensions (area) are small.

[0040] Finally, we propose an X-ray fluoroscopy system in which the X-ray source and the X-ray receiver can share position and orientation information to determine their mutual position and orientation. In the present invention, by setting a reference point in a basic coordinate system that is always referenced by the FPD and the gated X-ray source and does not move, the positions and orientations of the two can be determined relative to each other. Also, if an operator or the like determines the position and orientation of the FPD manually (semi-automatically), the position and orientation of the gated X-ray source is determined by autonomous control based on this information. In other words, if an operator or the like determines the position and orientation of the FPD, the position and orientation of the gated X-ray source will be determined automatically.

[0041] The X-ray detector (FPD) in the box and the synchronous X-ray source under the table each have their own independent motion mechanisms and object coordinate systems. The coordinate system of the FPD operating mechanism is called the item 1 coordinate system, and its reference point is set on the FPD slide table. The FPD slide table is installed on the ceiling of the FPD storage box, and these are supported and fixed by the FPD storage box stand. The coordinate system of the synchronous X-ray source operating mechanism is called the item-2 coordinate system, and its reference point is set on the X-ray source slide table. The X-ray source slide table is installed on the X-ray source support stand, which is supported and fixed by the FPD storage box stand.

[0042] To determine the relative position and orientation of the FPD and synchronized X-ray source, it is necessary to set up a fixed reference point for the basic coordinate system that can be constantly referenced by both. A good fixed reference point is a part that is fixed to the FD storage box stand. The X-ray source support stand was intentionally fixed on the FPD storage box stand. Therefore, the reference point for the basic coordinate system is set up at a position close to the center of the X-axis on the X-ray source support stand.

[0043] By providing a basic coordinate system, the FPD's Item 1 coordinate system and the synchronous X-ray source's Item 2 coordinate system can be linked and position and orientation information can be shared. This is called synchronization. This allows the synchronous X-ray source or X-ray receiver to determine their mutual position and orientation. This is called the "position and orientation determination function."

[0044] In basic mode, the position and orientation of the FPD is determined by the operator or other personnel through manual operation, or by semi-automatic operation using a stick or other device, either by the operator or an engineer in the control room. The determined position and orientation information of the FPD is synchronized with the object coordinate system of the synchronous X-ray source via the basic coordinate system, and the position and orientation of the synchronous X-ray source is determined by autonomous control. This is called the "coordinate vector synchronization method" for the synchronous X-ray source.

[0045] In addition, we will explain a method for improving the accuracy of the attitude of the synchronous X-ray source (the orientation of the X-ray source's emission direction). This is a method for optimizing the attitude by slightly oscillating the pan and tilt angles of the synchronous X-ray source after determining the position and attitude of the synchronous X-ray source using the coordinate vector synchronization method, and finding the attitude (angle) at which the X-ray intensity received by the FPD is maximized. It is also acceptable to slightly oscillate both the X and Y axes of the X-ray source slide table. This is called the "received light intensity attitude optimization method" for the synchronous X-ray source.

[0046] The device of the present invention is called an "integrated radiation exposure reduction X-ray fluoroscopy system." An integrated radiation exposure reduction X-ray fluoroscopy system is an X-ray fluoroscopy system primarily consisting of a shielded box housing an FPD, a table on which the patient is placed, and a gated X-ray source. These systems can capture images of the affected area over a wide range of fields of view in both the XY and rotational directions. The rails on both the XY axes were linear in the prototype system, but have been modified to elliptical arcs in the improved system. This increases the irradiation angle of the gated X-ray source and reduces the operating dimensions (area). Furthermore, the X-ray receiver (FPD) inside the box and the gated X-ray source under the table can mutually determine their positions and orientations via a reference coordinate system. For details of the prototype system, see Examples 1 and 2 below. For details of the improved system, see Examples 3 to 7 below. For details of the position and orientation determination function, see Examples 8 and 9 below.

[0047] Furthermore, by adding this new idea, the function of attenuating and absorbing scattered X-rays generated in all directions (front, side, and rear) from the patient's body, which is inherent to the FPD-embedded boxes described in Patent Documents 2 to 4, and reducing the radiation exposure dose to medical staff and patients, is not lost. Furthermore, what is called an end face box in Patent Documents 2 to 4 is called an FPD storage box in this invention. [Effects of the Invention]

[0048] The FPD-integrated box is an X-ray fluoroscopy device in which the FPD and X-ray source are separated and the FPD is housed in a shielded box. The FPD-integrated box reduces radiation exposure and the protection burden for medical staff and patients. However, there was no applicable X-ray source. The present invention embodies an "integrated exposure reduction X-ray fluoroscopy device" that has a synchronous X-ray source and its operating mechanism that can be applied to a conventional FPD built-in box. In addition, by adopting an elliptical path for the rails of both the X and Y axes, the irradiation angle of the synchronous X-ray source can be increased and the operating dimensions (area) can be reduced. Furthermore, if the operator manually (semi-automatically) determines the position and orientation of the FPD by synchronizing the coordinate vectors of the FPD and the synchronized X-ray source, the position and orientation of the autonomously controlled synchronized X-ray source can be determined automatically. [Brief explanation of the drawings]

[0049] [Figure 1] FIG. 1 is a bird's-eye view illustrating a prototype of an integrated radiation exposure reduction X-ray fluoroscopy device. [Figure 2] Figure 2 is an explanatory diagram showing the change in the irradiation angle of the synchronous X-ray source when the Y-axis rail is set to an elliptical arc path. (a) shows the state before improvement, and (b) shows the state before improvement. [Figure 3] Figure 3 is an explanatory diagram showing the change in the operating dimensions of the synchronous X-ray source when the X-axis rail is set to a circular arc path. (a) shows the state before improvement, and (b) shows the state before improvement. [Figure 4]Figure 4 is an explanatory diagram showing the effect of improving workability and FPD image quality with the elliptical arc-shaped top plate and X-axis rail. (a) shows the state before improvement, and (b) shows the state before improvement. [Figure 5] FIG. 5 is a bird's-eye view of an improved integrated radiation exposure reduction X-ray fluoroscopy device that has been improved using an elliptical arc path, etc. [Figure 6] FIG. 6 is an explanatory diagram showing a method for synchronizing the positions and orientations of the FPD and X-ray source of an integrated radiation exposure reduction X-ray fluoroscope. DETAILED DESCRIPTION OF THE INVENTION

[0050] An embodiment of the present invention will be described with reference to the drawings. It should be noted that the composite protective equipment and devices that provide a wide range of motion and their constituent parts shown here are merely examples and are not intended to limit the present invention.

[0051] In the remainder of this specification, the following terms are used in connection with names of devices and the like. Unless otherwise specified, the position of the X-ray tube will be described as an under-tube type X-ray fluoroscope placed under the table. The X-axis direction is perpendicular to the body axis of the patient. The axis of this orientation is called the X-axis. The Y-axis direction is the body axis direction of the patient. The axis of this orientation is called the Y-axis. The Z-axis direction is the vertical direction perpendicular to the X-axis and Y-axis. The axis of this orientation is called the Z-axis. The pan axis is the horizontal axis in the circumferential direction, and the tilt axis is the vertical axis. The inter-surface distance is the distance between the center position of the tilt axis of the synchronous X-ray source and the image receiving surface of the X-ray receiver. The moving dimension refers to the range of movement in the X or Y direction. The working dimensions (area) refer to the dimensions (area) required for the operation of the device. Boxes, tables, etc. are called protective devices (PD). The covers on the patient's body and the sheets under the patient's body are called protective implements (PI). In the past, there were types of X-ray receivers such as X-ray image intensifiers (II), but in recent years, flat panel detectors (FPDs) have become more compact and can be stored in boxes, etc. Therefore, X-ray receivers are represented by FPDs. Radiography rooms, examination rooms, treatment rooms, X-ray examination rooms, etc. are collectively referred to as "examination rooms, etc."

[0052] The remainder of this specification uses the following terms for types of X-rays: The primary source of radiation is the X-ray tube, and this primary X-ray beam is called "primary X-rays." Radiation that is scattered when primary X-rays hit a patient, examinee, part of the equipment, etc. is collectively called "scattered X-rays." Unless otherwise specified, X-ray energy refers to effective energy. Among scattered X-rays, X-rays that scatter forward at a small angle while roughly maintaining the energy of the primary X-rays (hereinafter referred to as "small-angle scattering") are called "small-angle scattered X-rays." Small-angle scattered rays occur in the irradiation field and its surroundings. The surroundings of the irradiation field refer to the area within 5 cm from the edge of the irradiation field, which is an area where forward scattered X-rays may occur due to small-angle scattering with one to several scatterings. Additionally, when primary X-rays are scattered by the patient's body or a table, etc., and are scattered forward at an angle of 0 to 45 degrees from the vertical to the angle of incidence (hereinafter referred to as "forward scattered X-rays"), X-rays scattered to the side at an angle of 45 to 135 degrees from the vertical (hereinafter referred to as "side scattered X-rays") are called "side scattered X-rays," and X-rays scattered backward at an angle of 135 to 180 degrees from the vertical (hereinafter referred to as "backscattered X-rays") are called "backscattered X-rays." Small-angle scattered X-rays are a type of forward scattered X-rays and are included in the number of small-angle scattered X-rays.

[0053] The examples of the present specification have the following configurations. In the first embodiment, an outline of an integrated radiation exposure reduction X-ray fluoroscopy device will be described. In the second embodiment, a bird's-eye view of a prototype of an integrated radiation exposure reduction X-ray fluoroscopy device will be described with reference to FIG. In the third embodiment, the concept of an improved device using an elliptical arc path or the like is explained. In the fourth embodiment, the effect of improving the irradiation angle by using the Y-axis rail of the X-ray source with an elliptical arc path will be described with reference to FIG. In the fifth embodiment, the effect of reducing the operating dimension by using the X-axis rail of the X-ray source with an arcuate path will be explained with reference to FIG. In the sixth embodiment, the elliptical arc-shaped top plate and X-axis rails will be used to explain the effect of improving the workability and image quality of the FPD, with reference to FIG. In the seventh embodiment, a bird's-eye view of an improved integrated radiation exposure reduction X-ray fluoroscopy device improved with an elliptical arc path or the like will be explained with reference to FIG. In the eighth embodiment, a method for determining the positions and orientations of the FPD in the box and the X-ray source below the table will be described with reference to FIG. In the ninth embodiment, a method for determining the position and attitude and controlling the precise attitude of a synchronous X-ray source will be described. Example 10 describes how the present invention can be used in interventional radiology procedures. [Example]

[0054] (Outline of the integrated radiation exposure reduction X-ray fluoroscopy device) In Example 1, an overview of the structure and configuration of an integrated radiation exposure reduction X-ray fluoroscopy device will be described. Here, the "integrated radiation exposure reduction X-ray fluoroscopy device" mainly consists of a table on which the patient's body is placed, a box on the table that houses an FPD, and an X-ray source below the table. This specification describes a prototype device and an improved version of the device. Note that what is called an end face box 5 in Patent Documents 2 to 4 is called an FPD storage box 18 in the present invention. Furthermore, what is called a box main body 4 in Patent Documents 2 to 4 is called a box main body 19 in the present invention.

[0055] During surgery, the patient is placed on a table. When using an under-tube type X-ray fluoroscopy system, the X-ray source is generally located below the table, and the X-ray receiver (FPD) is located above the patient. Without a box or additional shielding box (hereinafter referred to as "box, etc."), the patient's body, irradiated with primary X-rays from the X-ray source, emits scattered X-rays in all directions (hereinafter referred to as "all directions"), including 180 degrees above, 180 degrees below, and all 360 degrees to the sides, including up and down, within the examination room, etc. The definition of a box is a rectangular box that is placed on a table and has functional materials on the surface or inside where scattered X-rays are incident. An additional shielding box is a type of box that, in addition to shielding, has the ability to operate and see inside, with the aim of reducing exposure and reducing the protective burden for medical staff and patients. Note that functional materials are a general term for shielding materials and composite absorbing materials.

[0056] (Applicability of focal-skin distance to legal regulations, etc.) Integrated radiation exposure reduction X-ray fluoroscopy systems house the X-ray source under the table, shortening the X-ray tube focus-skin distance during fluoroscopy or imaging. A shorter focus-skin distance generally increases the patient's medical exposure. The shielding function of the device's box and table prevents increased medical exposure. However, the applicability to legal regulations and general rules must be confirmed. According to a Ministry of Health, Labor and Welfare notification (Iyaku-hatsu No. 0327004) issued on March 27, 2002, "The regulation regarding the X-ray tube focus-skin distance has been revised from 40 cm to 30 cm." Furthermore, Article 24-2 of the Medical Care Act Enforcement Regulations, "Notification of X-ray Equipment," states, "Equipment with an interlock to prevent the X-ray tube focus-skin distance of 30 cm or more or irradiation at a distance less than the required skin focus distance must be installed. However, for X-ray equipment used during surgery, the X-ray tube focus-skin distance may be 20 cm or more." On the other hand, Non-Patent Document 2 states that the focus-skin distance during fluoroscopy should be 20 cm or more. The focus-skin distance during radiography is set at 20 cm as the minimum allowable focus-skin distance (SSD) for intraoperative X-ray radiography. Therefore, in the present invention, the focus-skin distance (SSD) must be kept at 20 cm, and an interlock is provided to prevent irradiation if the SSD is less than 20 cm.

[0057] (Overview of the structure above the table of the integrated radiation exposure reduction X-ray fluoroscopy device) The box is installed in a three-dimensional manner to surround the radiation field corresponding to the affected area of ​​the patient's body. Each component of the box has the ability to shield X-rays. The box has no openings that connect to the outside space. By installing the box, it is possible to shield most of the scattered X-rays generated in the patient's body, including forward scattered X-rays that travel upward and side scattered X-rays that travel to the sides. The box is divided into two along the body axis, with the part on the head side of the patient's body called the FPD storage box and the part on the lower limb side called the main box.

[0058] The end face of the box, etc., in the body axis direction has a shielded viewing window through which medical personnel can see the inside from outside. In addition, the end face of the box in the body axis direction has a sleeve structure with a sleeve port, through which medical personnel can operate the inside from outside. A sleeve structure such as a shielding lead-containing arm sleeve is installed and blocks the opening to reduce scattered X-rays leaking to the side. It also reduces radiation exposure to the hands and arms of medical personnel.

[0059] A patient port is installed on the shorter end face of the box, etc., perpendicular to the body axis. The patient passes through the box in the direction of the body axis through the patient port. Parts of the patient's body outside the irradiation field and its surroundings, such as the head and limbs, can be placed in external space. This reduces the patient's medical exposure. A flexible curtain with shielding capabilities is installed on the patient port to close the opening between the box, etc. and the human body. This prevents scattered X-rays from leaking to the side.

[0060] In the case of the under-tube type, a top panel such as a box made of a material with better shielding performance can shield forward scattered X-rays, including small-angle scattered X-rays, from the radiation field and surrounding areas upward from the patient's body. Side scattered X-rays from the radiation field and other areas can be shielded by a shielding box or observation window. Backscattered X-rays from the patient's body downward can be shielded by a shielding sheet or similar. Furthermore, by combining these materials with a shielding material or composite absorbing material, scattered X-rays can be attenuated and absorbed.

[0061] Some boxes have a flat panel detector (FPD), which is an X-ray receiver, installed inside the box. This is called an "FPD-integrated box." In an FPD-integrated box, the X-ray receiver (FPD) and all of its operating mechanisms are housed inside the box. The FPD is an independent flat panel X-ray detector, and image information is extracted via a wired or wireless LAN connection. If the FPD has four motion axes, it can determine its position and orientation to a certain extent within the space of the box. Therefore, four or more motion axes are a necessary condition. Here, we show an example of an FPD motion mechanism with five motion axes (three X, Y, and Z axes, one rotation axis, and one tilt axis) installed inside the box. This motion mechanism is mainly composed of an FPD slide table, an extendable arm, and an FPD attitude control plate. Of this motion mechanism, the FPD slide table is fixed to the ceiling of the FPD storage box. The FPD storage box is supported by an FPD storage box stand. The FPD storage box stand has a gate-like shape that straddles the table. The FPD storage box stand has a sturdy structure that does not change shape due to distortion caused by its own weight. In other words, the FPD is supported by the sturdy FPD storage box stand via the motion mechanisms, including the FPD attitude control plate, extendable arm, and FPD slide table, and the FPD storage box.

[0062] In the FPD-integrated box, there are no objects penetrating the ceiling of the FPD storage box, so forward scattered X-rays can be reliably blocked by the top plate of the FPD storage box. This improves the image resolution of the X-ray receiver, which in turn reduces the X-ray output of the X-ray source. Reducing the X-ray output reduces exposure to radiation for medical staff and patients. In addition, because there is no C-arm or receiver arm, and no equipment around the box that would interfere with surgery, medical staff can easily perform surgery in a spacious area. By performing surgery in a shielded box with no openings as described above, the air dose rate in the examination room etc. can be reduced. This reduces unnecessary occupational exposure of medical personnel and avoids unnecessary medical exposure of the patient's head, trunk, limbs, etc. In particular, occupational exposure of the surgeon's head (eyes) and reproductive organs can be significantly reduced.

[0063] (Outline of the table for the integrated radiation exposure reduction X-ray fluoroscopy device) Generally, the basic role of a medical table is to support a patient's body. The table of this invention is defined as a flat table with a functional material on its top surface that has the ability to shield against scattered X-rays from a patient placed on it. A high-performance table is a type of table, and this definition is a medical table that transmits primary X-rays well and reduces scattering. A high-performance table can transmit primary X-rays well without scattering them by using a CFRP mesh or thin sheet on the table surface near the irradiation field. This function increases the rate at which primary X-rays are transmitted to the X-ray receiver. In addition, a high-performance table is composed of up to three steps: a top step, a middle step, and a bottom step. A functional material that reduces scattered X-rays is placed on the surface of each step.

[0064] Table 2 or a high-performance table (hereinafter referred to as "table, etc.") can reduce scattered X-rays generated in the patient's body and directed downward. Non-patent document 1 points out that in the case of an under-tube type X-ray fluoroscopy device, the number of photons of scattered X-rays directed downward is large. In a table, etc., a functional material with excellent shielding performance is placed on the surface of the table top of the top step, thereby attenuating and absorbing backscattered X-rays directed downward from the irradiation field of the patient's body and its surroundings. In a high-performance table, the upper side of the aperture plate of the middle step is further covered with a composite absorbing material, and the lower side is covered with a shielding material. The sliding absorber plate of the middle step is simply attached and installed locally except for the opening position of the intermediate slide table, and the upper side is covered with a composite absorbing material. This makes it possible to attenuate and absorb backscattered X-rays directed downward. The outer surface of the opening plate of the bottom step is covered with a shielding material, and the inner side is covered with a composite absorbing material. This makes it possible to attenuate and absorb backscattered X-rays directed downward.

[0065] Patent Document 4 explains the method and effects of a "combined case" consisting of an additional shielding box and a high-performance table. Combining two protective devices (PDs) allows for good penetration of primary X-rays and reduces the intensity of scattered X-rays emitted from the patient's body in all directions (upward, downward, and to the side), including the periphery of the irradiation field. This reduces the air dose rate in examination rooms, etc., thereby reducing radiation exposure for medical staff and patients. It also reduces the protective burden on medical staff.

[0066] (Overview of the structure under the table of the integrated radiation exposure reduction X-ray fluoroscopy device) In the case of the under-tube type, the X-ray source is installed under a table, etc. In this invention, an X-ray source that can freely change its own position and orientation based on instructed position and orientation information and can freely adjust the emission angle of the X-ray source is called a synchronous X-ray source.

[0067] Previously, Patent Document 3 stated that a commercially available portable X-ray source with adjustable position and angle would be installed separately on the floor below. It also stated that the portable X-ray source would be mounted on casters or other devices that could maintain its position and tilt angle. Meanwhile, it also stated that the X-ray receiver would be removed from the angiography device's C-arm, and only the X-ray source would be placed below a table or similar. However, Patent Document 3 also stated that there were issues remaining to be addressed with the above-mentioned X-ray source, and that a separate solution would be devised. This is because there was no known method for controlling the position and orientation of the FPD in the box and the X-ray source below the table, which are located separately. Patent Document 3 states that there are no commercially available floor-mounted external X-ray sources or the like that have a function for determining the position and orientation of the FPD and X-ray source.

[0068] The synchronous X-ray source is installed on an X-ray source support stand fixed to a sturdy FPD storage box stand. The X-ray source support stand is installed in an upper space away from the floor of an examination room or other facility. The synchronous X-ray source has two operating mechanisms: the X- and Y-axes of the X-ray source slide table, and the pan and tilt axes of the X-ray source two-axis attitude control plate. Each axis is equipped with a gear motor or other operating device. This means that the synchronous X-ray source has a total of four operating axes. The pan axis of the X-ray source two-axis attitude control plate is a hollow disk-shaped base mounted on the X-ray source support stand that rotates horizontally from 0 to 360 degrees on a slide bearing. The tilt axis is installed on the hollow disk of the pan axis. The tilt axis is a hollow disk that supports the synchronous X-ray source internally, and has two support shafts protruding from both ends. These support shafts are supported by bearings on the hollow disk of the pan axis. The surrounding components have a grooved structure to avoid contact with the synchronous X-ray source when tilted. This allows the tilt axis to rotate from -60 to +60 degrees from the vertical.

[0069] An X-ray source slide table is installed on the X-ray source support stand. By operating this, the position of the synchronous X-ray source on the X-axis and Y-axis can be determined. An X-ray source two-axis attitude control plate is installed on the X-ray source slide table. The synchronous X-ray source is installed on the X-ray source two-axis attitude control plate. The X-ray source two-axis attitude control plate can determine the attitude on two axes, the pan axis and the tilt axis. This allows the angle of the X-ray source to be freely changed on both the pan axis and the tilt axis. This allows the position and attitude to be freely changed, and the emission angle of the synchronous X-ray source to be freely adjusted.

[0070] In the prototype device, both the X-axis rail and Y-axis rail of the slide table are linear. The Y-axis rail is mostly located under the table. The Y-axis rail is fixed to the X-ray source support stand. The X-axis rail rests on the Y-axis rail and in the initial state protrudes to the left of the table. When performing right anterior oblique (RAO) imaging, the X-axis rail can remain in position overhanging the left side of the table. However, when performing left anterior oblique (LAO) imaging, the X-axis rail is moved to the right side of the table by the X-axis feed mechanism. After that, the position and orientation of the synchronous X-ray source are determined and imaging is performed. [Example]

[0071] (Explanation of a bird's-eye view of the prototype of the integrated radiation exposure reduction X-ray fluoroscopy device) In Example 2, a bird's-eye view of a prototype of the integrated radiation exposure reduction X-ray fluoroscopy device 110 shown in Fig. 1 is described. Note that Fig. 1 illustrates three mutually orthogonal axes: an X-axis, a Y-axis, and a Z-axis. For ease of explanation, the distal end direction of the Z-axis is referred to as "up" and the proximal end direction of the Z-axis is referred to as "down." In FIG. 1, a patient's body is placed on a table 2. Similarly, a box or the like is placed on top of the table 2. An independent synchronous X-ray source 100 is placed below the table 2. The synchronous X-ray source 100 is installed on an X-ray source support stand 101. The X-ray detector (FPD) 40 is housed in an FPD housing box 18 on the head side. The FPD housing box 18 is supported by an FPD housing box stand 37. An X-ray source support stand 101 is fixed to the FPD housing box stand 37.

[0072] The box or the like is divided into two parts: an FPD storage box 18 and a box body 19. The inner end face perpendicular to the body axis direction on the side where the box body 19 and FPD storage box 18 come into contact is an opening. A box end plate 45 is provided on the other outer end face. The table 2 is supported from the floor of an examination room or the like by a table support base 3. The FPD storage box 18 is supported from the floor of an examination room or the like by an FPD storage box stand 37. The box body 19 is placed on the table 2. The box body 19 is designed to slide on the table 2 toward the lower legs. Concave guides, keyways, etc. are provided on the table 2 to guide it during movement. The FPD storage box 18 also slides on the FPD storage box stand 37 toward the head by a distance of about half its total length. The FPD storage box stand 37 does not move in conjunction with this sliding. It is designed to slide on extension rails on the FPD storage box stand 37. The overall height of the FPD storage box stand 37 can be changed using a height adjustment rotary knob 38. By lowering the FPD storage box 18 using the height adjustment rotary knob 38, the FPD storage box 18 and the box body 19 come into close contact with each other without any openings. In addition, shielding material 96 and composite absorbing material 95 are placed on the surface of each part of the box where scattered X-rays are incident, so that scattered X-rays generated in the patient's body and directed in all directions can be reduced.

[0073] If the box is an additional shield box 17, the functions of viewing the inside and operating the inside are defined. The additional shield box 17 is a type of box 1. An observation window 6 is provided on the upper half of the end faces in the body axis direction of the FPD storage box 18 and the box body 19. A sleeve port 8 is provided on the lower half. The observation window 6 is a transparent plate with shielding properties. For example, it is a lead-containing acrylic plate or a lead-containing glass plate. A medical professional can view the inside of the device from the outside through the observation window 6. A sleeve structure is installed in the sleeve port 8 to close the opening. The sleeve structure can be a standard sleeve 9, a lead-containing arm sleeve 53 (hereinafter referred to as "sleeve, etc."), a lead-containing glove 54, or a gloveless port 60. A medical professional inserts their arm through the sleeve structure into the inside of a box or the like through the sleeve port 8 and performs a procedure or other operation inside the box. Some sleeves, etc., are short in length to prevent the shadow of the shielded image from being cast on the X-ray receiver (FPD) 40. Lead-containing gloves 54 are the most effective for reducing the emission of scattered X-rays in the horizontal direction. However, gloves are difficult to use. For medical professionals, the gloveless port 60 offers the best workability. Patent Document 4 describes a closed shielding cover 89 and other features that enhance the shielding of the gloveless port 60.

[0074] A patient port 20, sized to allow a human body to pass through, is installed on box end plate 45 on the outer end face of FPD storage box 18 and box body 19 in the direction perpendicular to the body axis. The box or the like is installed in a shape in which the patient's body 25 passes through patient port 20. In other words, the patient's head and lower limbs are exposed to the outside of the box or the like. This reduces the amount of medical radiation exposure to the patient. The patient port 20 is an opening without any shielding, and a large amount of scattered X-rays leaks into the examination room. For this reason, a flexible sheet or the like with a shielding function is installed in the patient port 20. Examples of the flexible sheet include a drape 22 or a strip-shaped curtain 88. For ideas such as a patient port lid 91 that improves the shielding of the patient port 20, see Patent Document 4.

[0075] An X-ray detector (FPD) 40 is housed inside the FPD storage box 18. The FPD operating mechanism consists of an FPD slide table 35, an extendable arm 47, and an FPD attitude control plate 48. The FPD slide table 35 is fixed to the ceiling of the FPD storage box 18. The extendable arm 47 is fixed to the FPD slide table 35. The FPD attitude control plate 48 is fixed to the extendable arm 47. The X-ray detector (FPD) 40 is fixed to the FPD attitude control plate 48. The FPD operating mechanism consists of an FPD slide table in the X and Y axes, an extendable arm in the Z axis and one rotation axis, and an FPD attitude control plate in one tilt axis. In other words, the FPD 40 has a total of five operating axes.

[0076] An FPD storage box top plate 16 and a box top plate 7 (hereinafter referred to as "top plates, etc.") are installed on the ceilings of the FPD storage box 18 and the box body 19. A connector 24 for connecting power, signals, etc. is installed on the box top plate 7. Small-angle scattered X-rays that are scattered at small angles by the patient's body hit the tabletop, etc. Small-angle scattered X-rays have high energy. In order to protect the eyes (crystalline lenses) of the surgeon, etc., the tabletop, etc. must be sufficiently shielded. For this reason, radiation attenuation material 97 with an atomic number of 92 or higher is installed in areas of the tabletop, etc. where high X-ray energy is irradiated. Patent Document 3 is referred to for the shielding materials for improving the shielding performance of the tabletop and the like against small-angle scattered X-rays, as well as the high-dose box shape and other innovations.

[0077] The patient body 25 is placed on the table 2. The table 2 is supported by a table support 3. A functional material with shielding ability is arranged on the table top 77. This can reduce scattered X-rays traveling downward from the patient body 25. The high-performance table 69 transmits primary X-rays well and reduces the emission of scattered X-rays. The high-performance table 69 has a CFRP mesh 83 or thin plate sheet 81 placed near the irradiation field 15 to suppress scattering of primary X-rays that pass through the table. The high-performance table 69 also consists of three steps: a top step 70, a middle step 74, and a bottom step 80, and composite absorbing materials 95 are placed in various locations. This attenuates scattered X-rays, absorbs linear energy (electron absorption), and reduces the emission of scattered X-rays. For details of the function and structure of the high-performance table, see Patent Document 2.

[0078] A synchronous X-ray source 100 located below the table 2 is installed on an X-ray source support stand 101. The X-ray source support stand 101 is fixed to the FPD storage box stand 37. If the synchronous X-ray source 100 has four motion axes, it can determine the position and orientation to a certain extent in the space below the table 2. Therefore, four or more motion axes are a necessary condition. Here, for example, the motion mechanism of the synchronous X-ray source 100 has two axes in the X- and Y-axis directions of the X-ray source slide table 102, and two axes of the pan axis and tilt axis of the X-ray source two-axis attitude control plate 103. In other words, the synchronous X-ray source 100 has a total of four motion axes.

[0079] An X-ray source slide table 102 is installed on an X-ray source support frame 101. An X-axis rail 104 rests on a Y-axis rail 105. By moving on the rail, the position (coordinates) of the synchronous X-ray source 100 on the X-axis and Y-axis can be determined. An X-ray source two-axis attitude control plate 103 is installed on the X-ray source slide table 102. The synchronous X-ray source 100 is installed on the X-ray source two-axis attitude control plate 103. The X-ray source two-axis attitude control plate 103 can determine the attitude (angle) of two axes, the pan axis 106 and the tilt axis 107. The tilt axis 107 rests on the pan axis 106. This allows the angle of the synchronous X-ray source 100 to be freely changed on two axes. These four axes allow the position and attitude of the synchronous X-ray source 10 to be freely changed, and the emission angle of the synchronous X-ray source to be freely adjusted.

[0080] In the prototype device, the X-axis rail 104 and Y-axis rail 105 of the X-ray source slide table 102 are both linear paths. In the initial state, the X-axis rail 104 protrudes to the left of the table 2. This position is sufficient for RAO imaging, but when LAO imaging is performed, the rail is moved to the right of the table 2 by the X-axis feed mechanism 109. After that, the position and orientation of the synchronous X-ray source 100 are determined and imaging is performed.

[0081] As described above, in the second embodiment, the configuration and structure of the integrated radiation exposure reduction X-ray fluoroscope 110 in Fig. 1 have been described. For details of the method for synchronizing the positions and orientations of the FPD in the box and the X-ray source below the table, see the eighth embodiment. [Example]

[0082] (Explanation of the concept of improved equipment using elliptical arc paths, etc.) One aspect of the present invention is an improved device in which the rail path of the slide table is an elliptical arc path or the like. By improving the method of determining the position and attitude and controlling the attitude of the FPD and the synchronized X-ray source using this technique, it is possible to reduce the dimensions required for the device's operation (hereinafter referred to as "operating dimensions"). Furthermore, for the same operating dimensions, the irradiation angle can be increased. In Example 3, the concept of an improved device employing an elliptical arc path or the like is explained for the slide table of the FPD and / or the synchronized X-ray source.

[0083] In general, angiography systems perform examinations in the right anterior oblique (RAO), left anterior oblique (LAO), and craniocaudal (CRA) directions, each with an irradiation angle of 30 to 45 degrees from the vertical. Some medical professionals prefer an irradiation angle of 60 degrees from the vertical. This means that the X-ray source and flat panel display (FPD) of the fluoroscopy system must be able to oscillate over a wide range along both the XY axes and in the rotational direction. The prototype of the integrated, radiation-reducing fluoroscopy system shown in Figure 1 was designed to enable irradiation angles of 45 degrees or more for RAO, LAO, and CRA. The improved system of the present invention aims for an irradiation angle of 60 degrees for each.

[0084] At the discretion of the surgeon, etc., it may be necessary to significantly change the FPD's orientation (angle) from one directly facing the patient's body, and obtain images that are significantly tilted. This is to confirm the orientation of catheters, etc., inside the body. Images tilted in the X-axis (perpendicular to the body axis) direction are called "X-axis tilted images." Images tilted in the Y-axis (body axis) direction are called "Y-axis tilted images." In these cases, the orientation (angle) of the FPD is primary, with the position being secondary.

[0085] When the FPD captures an X-axis tilt image, the gated X-ray source must move significantly in the X-axis direction. This increases the range of movement of the X-ray source slide table in the X-axis (perpendicular to the body axis) direction (hereinafter referred to as "movement dimension"). The X-ray source slide table moves in a direction that directly faces the gated X-ray source, using four axes depending on the area to be imaged. When the FPD captures a Y-axis tilt image, the gated X-ray source must move significantly in the Y-axis (body axis) direction.

[0086] When capturing X-axis tilt images with a large angle of view, if the X-axis rail of the X-ray source slide table is a straight path, the operating dimensions will be large, potentially increasing the installation size and floor space of the examination room. The same is true when capturing Y-axis tilt images using a straight path. If this is avoided and the installation size and floor space of the examination room for this device is limited to the area around the table, restrictions will arise, such as a smaller angle at which tilt images can be captured. One possible solution to these problems is to install rails on the X-ray source slide table that follow an elliptical or circular arc path (hereinafter referred to as "elliptical arc path, etc."). [Example]

[0087] (Improvement of irradiation angle by using an elliptical arc-shaped X-ray source Y-axis rail) As mentioned above, in FIG. 1, the Y-axis rail 105 of the synchronous X-ray source slide table 102 in the Y-axis (body axis) direction is a straight path. However, when capturing a Y-axis tilt image, the synchronous X-ray source 100 must move significantly in the Y-axis direction. Coupled with the increased distance from the irradiation field 15, the greater the tilt angle of the Y-axis tilt image, the greater the movement distance in the Y-axis direction. This means that the length of the Y-axis rail 105 of the X-ray source slide table 102 must be increased. In this case, the rail portion occupying the space below the table 2 must be increased, resulting in a larger device. To address this issue, we have devised an X-ray fluoroscopy device in which the Y-axis rail 105 of the X-ray source slide table 102 follows an elliptical arc path.

[0088] Figure 2 shows cross-sectional views of the integrated radiation exposure reduction X-ray fluoroscopy device 110 in the body axis direction before and after the improvement. Figure 2 shows the change in the irradiation angle of the synchronous X-ray source 110 when the Y-axis rail 105 is made elliptical arc-shaped. Figure 2(a) shows the original device before the improvement, in which the Y-axis rail 105 has a straight path. Figure 2(b) shows the improved device after the improvement, in which the Y-axis rail 105 has an elliptical arc path. In Figure 2, a synchronous X-ray source 100 and an X-ray source slide table 102 are stored in an FPD storage box stand 37. A Y-axis rail 105 of the X-ray source slide table 102 is fixed to the FPD storage box stand 37. In this diagram, an X-ray detector (FPD) 40 is located directly facing the heart of the patient's body. Directly facing this, at an irradiation angle of 0 degrees, is a synchronous X-ray source 100, shown by a solid line. The synchronous X-ray sources 100, with irradiation angles of 45 degrees or 60 degrees from the vertical, are shown by imaginary lines (two-dot chain lines) on the left and right of it.

[0089] In the upper part of Figure 2(a), the Y-axis rail 105 of the X-ray source slide table 102 is a straight path. The X-ray sources shown by imaginary lines (two-dot chain lines) on the left and right of the synchronous X-ray source 100 shown by a solid line have an irradiation angle of 45 degrees from the vertical. In the figure, the center line when the irradiation angle is 60 degrees from the vertical is shown by an imaginary line (two-dot chain line). The length of the Y-axis rail 105 is approximately 140 cm. When the irradiation angle is 45 degrees from the vertical, the Y-axis rail 105 of the X-ray source slide table 102 of the synchronous X-ray source 100 is almost contained within the FPD storage box stand 37, which has a length of approximately 150 cm in the body axis direction. However, as can be seen from the position of the center line, when the irradiation angle is 60 degrees, the Y-axis rail 105 does not fit within the FPD storage box stand 37. In other words, to achieve a 60-degree irradiation angle, the length of the Y-axis rail 105 needs to be extended to approximately 200 cm. This would not fit in the space below the table. Furthermore, assuming that the installation is to be accommodated within the space below the table, if the Y-axis rail 105 is a straight path, the irradiation angle is limited to 45 degrees from the vertical.

[0090] In the lower part of Figure 2(b), the Y-axis rail 105 of the X-ray source slide table 102 has an elliptical arc path. The path length of the elliptical arc path of the Y-axis rail 105 is approximately 165 cm. For the synchronous X-ray source 100, the irradiation angle of 0 degrees is indicated by a solid line, and the left and right irradiation angles of 60 degrees are indicated by imaginary lines (chain double-dashed lines). In other words, by making the path an elliptical arc of approximately 165 cm, the irradiation angle can be set to 60 degrees from the vertical. Moreover, the Y-axis rail 105 of the elliptical arc path is almost entirely contained within the FPD storage box stand 37, which is approximately 150 cm long.

[0091] In other words, by making the Y-axis rail 105 an elliptical arc path, the space below the table required to change the position and orientation of the synchronous X-ray source in the Y-axis direction is reduced. Also, assuming that it can be accommodated in the same space, the irradiation angle (CRA) in the Y-axis direction, which was 45 degrees from the vertical when the Y-axis rail 105 was a straight path, increases to 60 degrees from the vertical when the Y-axis rail 105 was an elliptical arc path. This means that the installation dimensions and area of ​​this device, in which the Y-axis rail 105 has an elliptical arc path, are smaller than the prototype device, and are equivalent to or smaller than those of a conventional C-arm angiography device.

[0092] Here, the geometric conditions that determine the irradiation angle when capturing a Y-axis tilt image are expressed numerically. For both the straight-line path in Figure 2(a) and the elliptical arc path in Figure 2(b), when the irradiation angle is 0 degrees, 45 degrees, or 60 degrees, the inter-surface distance between the center position of the tilt axis of the synchronous X-ray source and the image receiving surface (hereinafter referred to as the "inter-surface distance") is approximately 50 cm. The inter-surface distance varies from 45 cm to 55 cm depending on the tilt angle of the FPD, but the difference is not significant. Considering that the focus-skin distance mentioned above is 20 cm or more, the thickness of the human chest is 23 cm or less, and the subject-image receiving surface distance is several centimeters, it is understandable that the inter-surface distance, which is the total value, is approximately 50 cm. In this invention, the inter-surface distance is treated as 50 cm.

[0093] The Y-axis movement dimension of the FPD within the box is 65 cm, which is the same for all cases. Meanwhile, the linear shape and linear path length of the Y-axis rail in Figure 2(a), where the irradiation angle remains at 45 degrees from the vertical, are both 140 cm. The elliptical arc path length of the Y-axis rail in Figure 2(b), where the irradiation angle is 60 degrees from the vertical, is 165 cm. In other words, in an under-tube type device, the inter-face distance is constant at approximately 50 cm, and to obtain an irradiation angle of 45 degrees or more, the Y-axis rail path length must be more than twice the Y-axis movement dimension of the FPD. Note that the drawing of Figure 2 assumes that the pan and tilt axes of the synchronous X-ray source can rotate by more than 120 degrees.

[0094] Next, we will express the geometric state of the partial elliptical arc path of the Y-axis rail numerically. The approximate formula for the perimeter L of an ellipse that is close to a circle is L = π(a + b). Here, the length of the major axis of the ellipse is 2a, and the length of the minor axis is 2b. π is the constant pi. The exact formula will be omitted here. The length of the partial elliptical arc path is A·L, which is the product of the angular proportion A of the partial 360 degrees and the circumferential length L of the circle. The angular proportion A of the partial arc may be one-third (1 / 3) or one-half (1 / 2). However, for the purposes of this invention, it is unlikely that the length of the partial elliptical arc path will be less than one-third or more than one-half. For the purposes of the elliptical arc path of the Y-axis rail, one-half is the basic setting. Although the irradiation angle will be smaller, it is still acceptable if it is around one-third.

[0095] For the Y-axis rail, the length of the major axis, 2a, is the clearance under the table. The clearance under the table is calculated by subtracting the length of the table support from the total length of the table in the body axis direction. This is approximately 140 cm. The minimum value for the minor axis, 2b, is 0, which indicates a straight path. The maximum value for 2b is the height at which the synchronous X-ray source does not come into contact with the underside of the table at its highest position. Drawing considerations determined the maximum value for 2b to be 75 cm. This value is roughly the sum of the approximately 50 cm inter-face distance plus the approximately 20 cm height from the top of the Y-axis rail to the center of the synchronous X-ray source tilt axis. The maximum value for 2b corresponds to approximately 1.5 times the inter-face distance. For the purpose of the elliptical arc path, the maximum value for 2b is the default setting. The minor axis, 2b, can be defined as a value within the range from 0 to approximately 1.5 times the inter-face distance.

[0096] 2 shows an example in which an X-ray image is taken centered on the heart of the patient body 25. By moving the patient body 25 on the table 2 in the body axis direction, other parts can be imaged. For example, by moving the patient body 25 toward the head, the abdomen can be imaged. On the other hand, by moving and installing the FPD storage box stand 37, which secures the FPD storage box 18, FPD slide table 35, and X-ray source slide table 102, toward the head, the head of the patient body 25 can be imaged. The box main body 4 can be moved on the table 2 toward either the head or the lower limbs. [Example]

[0097] (Reduction of working dimensions by using an arc-shaped X-ray source X-axis rail) As in Example 4, in FIG. 1, the X-axis rail 104 of the synchronous X-ray source slide table 102 in the X-axis direction (perpendicular to the body axis) is a straight path. Similarly, when capturing an X-axis tilt image, the synchronous X-ray source 100 must move significantly in the X-axis direction. As the distance from the irradiation field 15 increases, the tilt angle of the X-axis tilt image increases, and the movement distance in the X-axis direction becomes even larger. In this case, the rail portion extending from the table 2 becomes larger, and the device itself becomes larger. Furthermore, the operating dimensions (area) required to operate the device become larger. To address this issue, in Example 5, an X-ray fluoroscopy device is devised in which the X-axis rail 104 of the X-ray source slide table 102 is an arcuate path.

[0098] Figure 3 shows cross-sectional views of the integrated radiation exposure reduction X-ray fluoroscopy device 110 in the direction perpendicular to the body axis before and after the improvement. Figure 3 shows the change in the operating dimensions of the synchronized X-ray source 110 when the X-axis rail 104 is made to follow an arc path. Figure 3(a) shows the original device before the improvement, in which the X-axis rail 104 follows a straight path. Figure 3(b) shows the improved device after the improvement, in which the X-axis rail 104 follows an arc path. The X-axis rail 104 of the X-ray source slide table 102 is attached to the Y-axis rail 105. Approximately half of the semicircular arc (approximately one-quarter of the partial arc) of the X-axis rail 104 of the X-ray source slide table 102 extends outward from the X-axis (perpendicular to the body axis) of the box or the like. This is the same as in conventional C-arm angiography systems. In Figure 3, the synchronized X-ray source 100 is stored in the FPD storage box stand 37. In Figure 3, the extending direction is to the left of the patient's body, where there is less movement of medical staff. The X-axis rail 104 is positioned to capture RAO. When capturing images on the opposite side of the X-axis rail 104, it slides on the Y-axis rail 105 and moves to the opposite side (the right side in Figure 3). The movement is performed by the X-axis feed mechanism 109. The X-axis rail 104 is positioned to capture LAO. In this diagram, an X-ray detector (FPD) 40 is positioned directly opposite the center of the body axis of a patient 25. Directly opposite this is a gated X-ray source 100, shown by a solid line. The gated X-ray source 100, which has an irradiation angle of 60 degrees from the vertical, is shown on both sides by imaginary lines (two-dot chain lines).

[0099] In Figure 3(a), the X-axis rail 104 of the X-ray source slide table 102 is a straight path. The X-ray sources shown by imaginary lines (two-dot chain lines) on the left and right of the synchronous X-ray source 100 shown by a solid line have an irradiation angle of 60 degrees from the vertical. When the irradiation angle is 60 degrees on a straight path, the X-axis rail 104 extends outward to the left by a distance of approximately 60 cm. The same is true for the right side shown by the imaginary line when imaging is performed with the X-axis rail 104 slid. The path length of the X-ray source slide table 102 is 170 cm. The table length is approximately 200 cm, so the operating area of ​​the prototype device is 3.4 square meters.

[0100] In Figure 3(b), the X-axis rail 104 of the X-ray source slide table 102 follows an arcuate path. The semicircular arc of the X-axis rail 104 during RAO imaging on the left side is shown by a solid line, and the semicircular arc during LAO imaging on the right side is shown by an imaginary line (two-dot chain line). The shape of the X-axis rail 104 differs from the path length due to sliding movement; it does not have to be a semicircular arc or quarter arc, but may be a partial arc of another length. The irradiation angle of the synchronous X-ray source 100 is 60 degrees from the vertical. The irradiation angle is the same as in the previous section. When the irradiation angle is 60 degrees on the arcuate path, the X-axis rail 104 extends outward by a distance of approximately 35 cm to the left. This is 25 cm shorter than in the case of a straight path. The operating dimension of the arcuate path is 40% shorter. The same is true for the right side shown by the imaginary line during LAO imaging when the X-axis rail 104 is slid.

[0101] Here, we numerically represent the geometric conditions that determine the beam angle when capturing an X-axis tilt image. For both the straight path in Figure 3(a) and the arc path in Figure 3(b), the inter-surface distance is approximately 50 cm when the beam angle is 0° / 60° from the vertical. This is the same as when capturing a Y-axis tilt image. The X-axis movement dimension within the FPD box is 40 cm, which is the same for all cases. On the other hand, the length of the straight shape and the linear path length of the X-axis rail in Figure 3(a) when the beam angle is 60° are both 170 cm. The elliptical path length of the X-axis rail in Figure 3(b) when the beam angle is 60° is also 170 cm. In other words, in an under-tube type device, the inter-surface distance is constant at approximately 50 cm, and to obtain a beam angle of 60° or more from the vertical, the path length of the X-axis rail must be more than twice the FPD's X-axis movement dimension. In addition, the drawing study for Figure 3 assumes that the pan axis and tilt axis of the synchronous X-ray source can rotate by 120 degrees or more.

[0102] Although the irradiation angle remained the same at 60 degrees from the vertical, by making the X-axis rail 104 a circular arc path, the operating dimension of the X-axis rail 104 of the synchronous X-ray source 100 is reduced. The reduced dimensions are shown as X1 and X2 in Figure 3(b). Both are approximately 25 cm. Therefore, X1 + X2 is 50 cm. This is the reduced operating dimension by changing the X-axis rail 104 from a straight path to a circular arc path. Since the length of the table is approximately 200 cm, the reduced operating area by making it a circular arc path is 1.0 square meter. The overall working area of ​​the improved device is 2.4 square meters, so this is approximately 40% of that. In other words, the working area is clearly smaller than that of the prototype device or conventional C-arm angiography devices.

[0103] Next, the path length of the X-axis rail and the geometric state of the partial arc shape are expressed numerically. The circumference of the circle is l = 2πr, where r is the radius of the circle and π is the constant pi. The length of the partial arc is l·A, the product of the angular fraction A of 360 degrees and the circumference l of the circle. For the purposes of the device, the arc path length is half the angular fraction A (semi-arc). The path length is unrelated to the length of the partial arc of the X-axis rail. This is because the short X-axis rail slides within the semi-arc path length. The partial arc shape of the X-axis rail is expressed by the angle ratio A. A can be one-quarter (1 / 4), one-third (1 / 3), or one-half (1 / 2). However, due to the configuration of the device, it is difficult to imagine a configuration that exceeds one-half of the semicircular path length. However, a device with a half-length semicircular rail is possible. In this case, the X-axis feed mechanism is unnecessary. However, this is not desirable because the device scale would be equivalent to that of a C-arm angiography unit. A device with a quarter-length partial arc X-axis rail is also possible. However, this is not desirable because it would require frequent operation of the X-axis feed mechanism, resulting in poor work efficiency. A partial arc shape of one-third is preferable for the X-axis rail. Therefore, the default setting for the X-axis rail is a one-third semicircular arc shape. In this device, the X-axis rail is initially located on the left side, allowing for RAO imaging. The X-axis rail is slid during LAO imaging.

[0104] On the other hand, the radius r of the partial arc is determined by a certain range of values ​​depending on the configuration of the X-ray fluoroscopy device. In practice, it is desirable for the radius r to be a partial arc with a value similar to the inter-surface distance. As mentioned above, the inter-surface distance is approximately 50 cm. In this case, the radius r is also approximately 50 cm. If the radius r of the partial arc is small, the height of the end of the semicircular arc path will be low and the linear distance between the end points will be short. This is not desirable because a large irradiation angle cannot be obtained. However, by examining the drawing, it is possible to allow up to about 0.7 times the distance between the faces. On the other hand, if the radius r of the partial arc is large, the end of the semicircular arc path will be located far from the patient's body. This is not desirable because it increases the operating dimension (area) of the device. However, it is still acceptable up to about 1.5 times the inter-surface distance.

[0105] As described above, by changing the X-axis rail 104 of the X-ray source slide table 102 from a straight path to an arcuate path, the operating dimensions and operating area of ​​the X-axis rail 104 of the synchronous X-ray source 100 are reduced by about 40%. Also, the positions of the synchronous X-ray source 100 indicated by the imaginary lines on the left and right in Figure 3(b) are positions with some margin from the rail ends. In other words, by changing the X-axis rail 104 to an arcuate path, the irradiation angle (RAO and LAO) in the X-axis direction can be made even larger than 60 degrees from the vertical.

[0106] The X-axis rail 104 of the X-ray source slide table 102 rests on the Y-axis rail 105. As mentioned above, the operating dimensions of the X-ray source slide table 102 are larger on the left and right. Note that the left side of the box, etc., here refers to the patient's left arm side, and the right side refers to the patient's right arm side. In the initial state, the X-axis rail 104 protrudes outward from the box etc. The protruding dimension is slightly smaller than that of a conventional C-arm type angiography apparatus. The X-axis rails 104 of the X-ray source slide table 102 may be provided on both the left and right sides. However, X-axis rails 104 that extend beyond the table 2 will interfere with the movement of medical personnel during surgery. Since treatment can be performed on only one side of a box, etc., it is best to provide X-axis rails 104 on only one side. The left and right initial positions of the X-axis rail 104 are such that they extend out to the side where the catheter is not inserted (generally the left side). When imaging from the other side during an examination, etc., the X-axis rail 104 is moved to the opposite side from its initial position. During an examination, medical personnel in the examination room generally retreat to the control room or behind a shield.

[0107] In this way, the advantages of changing the rail of the X-ray source slide table 102 fixed to the FPD storage box stand 37 and installed under the table 2 from a straight path to an elliptical arc path or a circular arc path are as follows. If the Y-axis rail 105 of the X-ray source slide table 102 is made to have an elliptical arc path, the operating dimensions of the X-ray source can be reduced even if the irradiation angle (CRA) of the synchronous X-ray source 100 is set to 60 degrees from the vertical. This allows the Y-axis rail 105 to be stored in the space below the table 2. If the X-axis rail 104 of the X-ray source slide table 102 is made to follow an arcuate path, the operating dimensions and operating area are reduced by about 40% compared to a linear path. Also, the irradiation angle (RAO and LAO) in the X-axis direction of the synchronous X-ray source 100 can be made even larger than 60 degrees. [Example]

[0108] (The elliptical arc-shaped top plate and rails improve workability and FPD image quality) In the prototype of the integrated radiation exposure reduction X-ray fluoroscopy system shown in FIG. 1, the top of the box or the like is horizontal. Therefore, the rail 63 in the X-axis direction (perpendicular to the body axis) of the FPD slide table 35 stored inside the box or the like is a straight path. However, during surgery, the X-ray detector (FPD) 40 is manually (semi-automatically) moved by the surgeon or the like inside the box in an elliptical arc shape on a straight path that follows the shape of the upper chest and abdomen of the patient body 25 in the direction perpendicular to the body axis. Even if it is moved by operating a stick, it is time-consuming to operate it in an elliptical arc shape. Obviously, it is easier for the surgeon or the like to move the FPD 40 in the X-axis direction in an elliptical arc path that follows the shape of the upper part of the patient body 25. Furthermore, the FPD 40 accurately faces the patient body 25. Therefore, the FPD 40, which has a grid arranged perpendicular to the image receiving surface, is less susceptible to the effects of scattered X-rays inside the box, etc., resulting in clearer X-ray image quality.

[0109] In order for the FPD 40 to move in the X-axis direction following the shape of the upper side of the patient's body 25, some ingenuity is required for the rail 63 of the FPD slide table 35 in the X-axis direction. To achieve this, the ceiling surface of the FPD storage box 18 is curved upwardly convexly to match the shape of the upper side of the patient's body 25, and the rail 63 of the FPD slide table 35 in the X-axis direction is shaped to follow this. The curved shape is an elliptical arc that matches the shape of the upper surface of the patient when lying supine. As a result, the FPD moves along an elliptical arc path in the X-axis direction, and the image receiving surface naturally faces the patient's body without any angle adjustment, making it easy to determine the position and orientation of the FPD. Furthermore, the image quality of the FPD 40 is improved because it is less susceptible to the effects of scattered X-rays. The rail 62 in the Y-axis (body axis) direction of the other FPD slide table 35 may remain a straight path even if it conforms to the shape of the upper side of the patient body 25.

[0110] Figure 4 shows how the operating conditions of the FPD 40 change with the elliptical arc-shaped top plate and X-axis direction rail 63. Figure 4(a) shows the device before improvement, where the X-axis direction rail 63 has a straight path. Figure 4(b) shows the device after improvement, where the X-axis direction rail 63 has an elliptical arc path. The X-ray detector (FPD) 40 is housed in a box or the like, so it must only operate within that spatial range. In addition, care must be taken to prevent the edge of the FPD 40 from colliding with the wall of the box or the like.

[0111] In Figure 4(a), which shows the state before the improvement, it can be seen that of the operating mechanism of the FPD 40, only the FPD attitude control plate 48 is tilted. The position and attitude of the FPD 40 is operated manually (semi-automatically) by the surgeon, etc. Unless the surgeon, etc. is extremely dexterous, it is difficult to manually and accurately determine the position and attitude of the FPD 40 inside the box to face this position and attitude. Because the surgeon, etc. wears surgical gloves, etc., it is even more difficult to accurately determine the position and attitude. For this reason, it is considered normal for there to be an error in the position and attitude of the FPD 40 in Figure 4(a).

[0112] In the improved version of Figure 4(b), the FPD 40 is positioned and oriented so that it faces the patient 25 simply by moving it in the X-axis direction. This is because the rail 63 in the X-axis direction is an elliptical arc path that follows the upper surface of the patient's body. This eliminates the need for an operator to laboriously determine the position and orientation of the FPD 40 manually (semi-automatically) inside a box, etc. In other words, it is easy to work with. Furthermore, the image quality of the FPD 40 is improved because it is less susceptible to the effects of scattered X-rays. As described above, the position and orientation of the synchronous X-ray source 100 are determined by autonomous control based on the position and orientation information of the FPD 40. Therefore, there is no need for an operator or the like to operate it.

[0113] In the improved version of Figure 4(b), there is one point to note regarding the position and orientation determination function of the FPD 40. This is related to the operation mechanism of the FPD 40 when capturing X-axis or Y-axis tilted images. As explained in the previous section, it is now easy to determine the position and orientation of the FPD 40 so that it faces the patient body 25. However, if the operation mechanism of the FPD 40 is the five-axis type mentioned above, it is difficult to determine the position and orientation of the FPD 40 for capturing X-axis or Y-axis tilted images. The extendable arm 47, which is the Z-axis of the FPD 40, can extend, retract, and rotate, but the Z-axis cannot be tilted in its current state.

[0114] To address this issue, one tilt axis that tilts the Z axis is added. The Z-axis tilt axis joint 111 is installed at the base of the extendable arm 47. In other words, the movement mechanism of the FPD 40 has a total of six axes: three axial directions (X, Y, and Z), one rotational axis, and two tilt axes. This makes it possible to move the FPD 40 further inside a box or the like and determine its position and orientation in all directions in order to capture images tilted along the X or Y axis. In Figure 4(b), the imaginary line (chain double-dashed line) shows the position and orientation of the FPD 40 with an additional Z-axis tilt axis. At the same time, the synchronized X-ray source 100 is tilted to an irradiation angle of approximately 90 degrees. By adding an additional Z-axis tilt axis to the FPD 40 movement mechanism, it is possible to obtain X-ray fluoroscopic images of a nearly vertical cross section. The irradiation angle (RAO and LAO) in the X-axis direction for a total of six axes, including the addition of the additional Z-axis tilt axis to the FPD 40 movement mechanism, is equal to or greater than that of a conventional C-arm angiography system.

[0115] Based on the above, the advantages of making the rail 63 in the X-axis direction of the FPD slide table 35 in the box an elliptical arc path are as follows. If the movement of the FPD 40 in the X-axis direction is made an elliptical arc path, the precision of manual (semi-automatic) position and orientation determination by the surgeon etc. will improve, making the work easier. Also, since the position and orientation of the FPD 40 and the synchronous X-ray source 100 are determined to be directly facing each other without error, the X-ray image quality will be clearer. Furthermore, if one Z-axis tilt axis is added, the position and orientation of the FPD 40 can be determined further in all directions. [Example]

[0116] (Explanation of a bird's-eye view of an improved device that uses an elliptical arc path, etc.) In Example 7, a bird's-eye view of an improved integrated radiation exposure reduction X-ray fluoroscope 110 that has been improved by adopting an elliptical arc path or the like is described with reference to Figure 5. The basic configuration and structure of the integrated radiation exposure reduction X-ray fluoroscope 110 was described in Example 2 with reference to Figure 1, so here, the explanation will focus on the parts that have been changed due to the adoption of an elliptical arc path or the like. Note that, as in Figure 1 of Example 2, there is a reference point 112 of the reference coordinate system on the X-ray source support pedestal 101 fixed to the FPD storage box pedestal 37. Note that for details of a method for synchronizing the position and orientation of the FPD inside the box and the X-ray source below the table, see Example 8. 5, a Y-axis rail 104 having an elliptical arc path of an X-ray source slide table 102 is fixed to an X-ray source support frame 101. The X-axis rail 104 is mounted on a Y-axis rail 105. The synchronous X-ray source 100 is mounted on the X-axis rail 104.

[0117] (Elliptical arc path of the Y-axis rail of the X-ray source slide table) The Y-axis rail 105 of the X-ray source slide table 102 has been changed from a straight path in Figure 1 to an elliptical arc path in Figure 5. In Figure 5, the Y-axis rail 105 is almost entirely contained within the space below the table 2. When capturing Y-axis tilt images, the straight path was 45 degrees from the vertical, but the elliptical arc path allows for capture of images in the craniocaudal direction (CRA) at an irradiation angle of 60 degrees from the vertical. The installation dimensions and area of ​​the improved device, in which the Y-axis rail 105 has an elliptical arc path, are the same as those of the original device, but are smaller than those of a conventional C-arm angiography device.

[0118] (Circular path of the X-axis rail of the X-ray source slide table) The X-axis rail 104 of the X-ray source slide table 102 has been changed from a straight path in FIG. 1 to a circular arc path in FIG. 5. The installed circular arc path X-axis rail 104 is one half of a semicircle. It protrudes outward to the left side of the patient's body (the other side of table 2 in FIG. 5). In reality, a cover is attached to the protruding portion, but this is omitted in FIG. 5. The protruding direction in FIG. 5 is the side with less movement of medical staff. In the initial state, there is no protrusion on the right side (the front side in Figure 5), so surgeons can easily perform medical procedures without being restricted by the location of the X-ray source. In this position, right anterior oblique (RAO) imaging is possible at an irradiation angle of 60 degrees or more from the vertical. When imaging the opposite side, left anterior oblique (LAO), the X-axis rail 104 slides on the Y-axis rail 105 to the opposite right side (the front side in Figure 5). This movement is performed by the X-axis feed mechanism 109. The X-axis feed mechanism 109 is the same as that used in C-arm angiography systems. In Figure 5, the X-axis rail 104 in this case is represented by an imaginary line (two-dot chain line). This allows left anterior oblique (LAO) imaging at an irradiation angle of 60 degrees or more.

[0119] With RAO and LAO, if the FPD40 motion mechanism has a total of five axes, imaging is possible up to 60 degrees, and if one tilt axis in the Z-axis direction is added, for a total of six axes, imaging is possible up to a maximum of nearly 90 degrees. If the X-axis rail 104 of the X-ray source slide table 102 is made into an arc path, the operating dimensions and operating area are reduced by about 40% compared to a straight path. Also, if the FPD40 motion mechanism is changed from a total of five axes to a total of six axes by adding a joint 111 on the Z-axis tilt axis, imaging with an irradiation angle of 90 degrees is possible. This irradiation angle in the X-axis direction (RAO and LAO) is equal to or greater than that of conventional C-arm angiography systems.

[0120] (Explanation of the elliptical arc path of the rail in the X-axis direction of the FPD slide table) The shape of the top plate 16 of the FPD storage box 18 and the path of the X-axis direction rail 63 of the FPD slide table 35 inside the box have been changed from the straight shape in Figure 1 to an upwardly convex elliptical arc shape in Figure 5. This elliptical arc shape follows the surface shape of a human body lying on its back. By changing the X-axis direction rail 63 to an elliptical arc path, the X-ray detector (FPD) 40 will obviously face the patient body when moved in the X-axis direction. This improves the accuracy of manual (semi-automatic) position and orientation determination by the operator, etc., and makes the work easier. At the same time, an FPD 40 that faces the patient body 25 with high accuracy is less susceptible to scattered X-rays inside the box, etc., resulting in clearer X-ray image quality. [Example]

[0121] (Method for determining the position and orientation of the FPD inside the box and the X-ray source under the table) One aspect of this invention is a method for determining the position and orientation of an FPD and an X-ray source. This involves synchronizing the position and orientation information of two independent operating mechanisms: a flat panel detector (FPD) in an under-tube box and a synchronous X-ray source located below the table. To achieve this, a reference coordinate system and its reference point are established that can always indicate coordinates relative to the article coordinate system that indicates the movement dimensions of both.

[0122] As a result, the article 1 coordinate system and the article 2 coordinate system are linked (hereinafter referred to as "linked") via the reference coordinate system. In the present invention, the exchange of position and orientation information between these linked coordinate systems is called "synchronization." That is, in the present invention, the two article coordinate systems are linked to synchronize the position and orientation information. The synchronized position and orientation information allows the FPD and the synchronized X-ray source to determine their mutual positions and orientations. Here, determining their mutual positions and orientations means not only that the FPD and the synchronized X-ray source are directly facing each other, but also that they can both be determined to have pre-programmed positions and orientations.

[0123] In Example 8, two article coordinate systems and their reference points, as well as a reference coordinate system and its reference point, are described. The operation of the FPD is a kind of manual manipulator. Furthermore, the operation of the synchronous X-ray source is a kind of autonomously controlled surveillance camera. In other words, this is similar to the operation of an automatic surveillance camera tracking the movement of a manual manipulator. Note that here, we deal with the position, orientation, and coordinate transformation in rigid body motion within the scope of statics. Furthermore, the orientations of the reference coordinate system, article 1 coordinate system, and article 2 coordinate system are always the same. They never face in opposite directions. This is a simple system in terms of control technology, and its content does not go beyond the scope of conventional technology for controlling robots, etc. Therefore, mathematical formulas and coordinate transformation formulas, etc., are not described.

[0124] (Item 1 coordinate system and its reference point) The item 1 coordinate system represents the motion and range of the FPD 40. The movement mechanism of the FPD 40 is an FPD slide table 35 in the X and Y axes, an extendable arm 47 in the Z axis and one rotation axis, and an FPD attitude control plate 48 in one tilt axis. The FPD 40 has a total of five movement axes. The FPD storage box 18 is supported by an FPD storage box stand 37. An FPD slide table 35 is installed on the ceiling of the FPD storage box 18. An extendable arm in the Z-axis direction is installed on the FPD slide table 35 in the X- and Y-axis directions. The extendable arm can also rotate. An FPD attitude control plate 48 is installed on the extendable arm. An FPD 40 is installed on the FPD attitude control plate 48, which can change the tilt of the plate in one direction.

[0125] The FPD storage box 18 is fixed to an FPD storage box stand 37. The FPD storage box stand 37 does not move except when adjusting the height relative to the table 2. Therefore, the coordinate system that controls the FPD has the FPD slide table 35 fixed to the FPD storage box 18 as its reference point.

[0126] (Item 2 coordinate system and its reference point) The object-2 coordinate system represents the movement and range of the synchronous X-ray source 100. The movement mechanism of the synchronous X-ray source 100 is composed of four axes in total: the XY axis directions of the X-ray source slide table 102 and two axes, the pan axis and tilt axis of the X-ray source two-axis attitude control plate 103. Pan means movement in the horizontal direction, and tilt means movement in the vertical direction. The synchronous X-ray source 100 must be installed under the table and irradiate at a wide angle. The synchronous X-ray source 100 is installed on an X-ray source support stand 101 provided on the FPD storage box stand. An X-ray source slide table 102 is installed on the X-ray source support stand 101. An X-ray source two-axis attitude control plate 103 is installed on the X-ray source slide table 102. The synchronous X-ray source 100 is installed on the X-ray source two-axis attitude control plate 103, which can change the angle on two axes, the pan axis and the tilt axis.

[0127] The terms pan axis and tilt axis are used for imaging sensors and monitoring sensors (hereinafter referred to as "imaging sensors, etc."). Imaging sensors, etc., rotate horizontally around the pan axis and tilt up and down around the tilt axis. While imaging sensors, etc., are cameras that receive visible light, the synchronous X-ray source of the present invention is an X-ray source that emits X-rays. Although there are differences in the radiation quality between visible light and X-rays and differences in the incidence and emission, the configurations of these devices are similar. This operating mechanism allows the X-ray source to move in the X and Y directions within the range of the X-ray source slide table, allowing adjustment of the irradiation angle to approximately 120 degrees, from 0 to 360 degrees horizontally along the pan axis and from -60 to +60 degrees from the vertical along the tilt axis. While such a wide range of irradiation angles is not necessary, the irradiation angle required for FPD attitude control is satisfied.

[0128] The FPD storage box stand 37 does not move except when adjusting the height relative to the table 2. Even if the height changes, the positional relationship between the synchronous X-ray source 100 and the FPD 40 does not change. The coordinate system that controls the synchronous X-ray source 100 has the X-ray source slide table 102 as its reference point.

[0129] As described above, the FPD 40 and the synchronous X-ray source are supported by a common FPD storage box mount that does not move or change position. The FPD 40 and its movement mechanism in the FPD storage box and the synchronous X-ray source and its movement mechanism are installed on the same level, the FPD storage box mount. This makes it possible to set a common reference point.

[0130] (reference coordinate system and its reference point) The reference coordinate system must be set at a location that does not change and can always be referenced from both the FPD slide table and the X-ray source slide table. The FPD slide table 35 is fixed to the ceiling of the FPD storage box 18. The FPD storage box 18 is fixed to an FPD storage box pedestal 37. On the other hand, the X-ray source slide table 102 is fixed to an X-ray source support pedestal 101. The X-ray source support pedestal 101 is fixed to the FPD storage box pedestal 37. In other words, both the FPD slide table 35 and the X-ray source slide table 102 are fixed to the FPD storage box pedestal 37 via members whose positions do not change due to movement. Therefore, in the present invention, a reference point 112 of the reference coordinate system is set near the center of the X-ray source support pedestal 101 fixed to the bottom of the FPD storage box pedestal 37. The X-ray source support pedestal 101 is located below and at a distance from the table 2.

[0131] The FPD storage box stand 37 can be moved within the examination room using wheels such as rollers. It is also equipped with a height-adjustment rotary knob 38. When attaching or detaching the FPD storage box 18 from the table 2, it is necessary to lift the FPD storage box 18 by approximately one to several centimeters. The height-adjustment rotary knob 38 adjusts the height of the entire FPD storage box stand 37 in the vertical direction. Therefore, adjusting or moving the height using the height-adjustment rotary knob 38 does not change the relative positions and orientations of the reference coordinate system and the two object-based coordinate systems described above.

[0132] FIG. 6 is a schematic diagram showing the correlation between the reference coordinate system, the item 1 coordinate system, and the item 2 coordinate system used in control, based on the above content. The XYZ axis directions of the reference coordinate system Σ0 are expressed as X0-Y0-Z0. In the operation mechanism of the FPD 40 in the article 1 coordinate system, the XY axis directions of the FPD slide table 35 are expressed as X1-Y1. The Z axis direction of the telescopic arm 47 is expressed as Z1. The rotation direction of one axis about the Z axis is expressed as θ11. The tilt direction of one axis from the Z axis by the FPD attitude control plate 48 is expressed as θ12. In the operation mechanism of the synchronous X-ray source 100 in the object 2 coordinate system, the XY axis direction of the X-ray source slide table 102 is expressed as X2-Y2. The pan axis (horizontal rotation) of the X-ray source two-axis attitude control plate 103 is expressed as θ21. The tilt axis (up and down of the field of view due to rotation) is expressed as θ22 from above the pan axis. Here, we have shown an example in which the item 1 coordinate system is composed of a total of five axes, and the item 2 coordinate system is composed of a total of four axes. Although attitude control becomes slightly more complicated, the number of axes can be greater. If the number of axes is small, a position and attitude will arise in which the position coordinates cannot be controlled, but this is acceptable as long as it does not cause any problems.

[0133] The solid arrows in Figure 6 indicate the flow of position and orientation information from "position and orientation of FPD 40 → object 1 coordinate system Σ1 → reference coordinate system Σ0 → object 2 coordinate system Σ2 → position and orientation of synchronous X-ray source 100." When the operator manually or semi-automatically determines the position and orientation of the FPD 40's operating mechanism, the synchronized position and orientation information is transmitted to the operating mechanism of the synchronous X-ray source 100 using the linked coordinate system, and the position and orientation of the X-ray emission change through autonomous control. The changes in the position and orientation of the synchronous X-ray source 100 are indicated by open arrows. The X-rays emitted from the synchronous X-ray source 100 toward the FPD 40 after the position and orientation are determined are indicated by dashed lines. In this invention, the function of synchronizing the operation of the FPD 40 operating mechanism and the operation of the synchronous X-ray source 100 to determine the position and orientation is called the "position and orientation determination function." A method of determining the position and orientation by synchronizing the coordinate system of the synchronous X-ray source with the FPD via a link will be described in Example 9. [Example]

[0134] (Method for determining the position and attitude of a synchronous X-ray source and controlling its precise attitude) In the ninth embodiment, a method for determining the position and attitude and controlling the precise attitude of a synchronous X-ray source by synchronizing the position and attitude information with an X-ray detector (FPD) will be described. This paper focuses on the prototype and improved versions of the integrated radiation exposure reduction X-ray fluoroscopy system described above. As an example, we will describe a method for manually (semi-automatically) determining the position and orientation of the X-ray detector (FPD), and a method for determining the position and orientation and precise orientation control by autonomous control of the synchronized X-ray source by linking these coordinate systems and synchronizing the position and orientation information.

[0135] The spatial representation of an object in three-dimensional space is its position and orientation. To express these mathematically, two types of coordinate systems are required: a reference Cartesian coordinate system and an Cartesian coordinate system fixed to the object. The former is called the reference coordinate system, and the latter is called the object coordinate system. These objects are assumed to be rigid bodies (objects whose shape does not change). In the present invention, the reference coordinate system is on a synchronous X-ray source support stand fixed to the FPD storage box stand. There are two objects: an FPD and a synchronous X-ray source. Object 1 is an X-ray receiver (FPD). Object 2 is a synchronous X-ray source. Both have independent operating mechanisms. The two object coordinate systems exist on the FPD storage box stand. The reference coordinate system and the two object coordinate systems are always correlated.

[0136] As in Example 8, the reference coordinate system and its reference point are set on the X-ray source support stand fixed to the FPD storage box stand of the integrated radiation exposure reduction X-ray fluoroscopy device. The item 1 coordinate system and its reference point are set on the FPD slide table fixed to the ceiling of the FPD storage box supported by the FPD storage box stand. The item 2 coordinate system and its reference point are set on the X-ray source slide table fixed to the X-ray source support stand supported by the FPD storage box stand.

[0137] The operating mechanism for the FPD inside the FPD storage box consists of an FPD slide table, an extendable arm, and an FPD attitude control plate. There are many commercially available products for the XY-axis FPD slide table, and the control device for a general-purpose robot can be applied. There are also many commercially available products for the Z-axis extendable arm, which similarly lifts and rotates, and the control device for a manipulator on a general-purpose robot can be applied. There are also many commercially available products for the FPD attitude control plate, which mounts the FPD and controls its attitude in the tilt direction, and the control device for the FPD attitude control plate (tilt) on a general-purpose robot can be applied. Therefore, the operating mechanism of the X-ray detector (FPD) can be handled by applying modern general-purpose technology. At the start of surgery, the FPD is stopped at an initial position within a box defined as the reference point of the object 1 coordinate system synchronized with the reference coordinate system.

[0138] The operating mechanism for the synchronous X-ray source is an X-ray source slide table and an X-ray source two-axis attitude control plate mounted on it. The synchronous X-ray source is attached to the X-ray source two-axis attitude control plate. As with the FPD slide table mentioned above, there are many X-ray source slide tables available on the market, and the control device can be one from a general-purpose robot. In addition, there are many X-ray source two-axis attitude control plates for the pan and tilt axes that are used in imaging sensors, etc., and the control device can also be one from these. Therefore, the operating mechanism of the synchronized X-ray source can also be handled by applying modern general-purpose technology. At the start of surgery, the synchronized X-ray source stops at the initial position under the table, which is defined as the reference point of the object-2 coordinate system synchronized with the reference coordinate system.

[0139] In the case of an X-ray fluoroscopy system in which the FPD is housed inside a box, the position (coordinates) and orientation (angle) of the FPD on the patient's body are decided by the surgeon or assistant (hereinafter referred to as "surgeon, etc.") who knows the purpose of the surgery. Since the system does not automatically identify the affected area and operate, there is no need for the object detection method often seen in recent patent applications for industrial item sorting robots. As with conventional C-arm angiography systems, the surgeon, etc., operates a stick on the device to determine the position and orientation of the X-ray receiver according to the purpose of the surgery. In other words, determining the position and orientation of the FPD is a semi-automatic operation that mainly relies on manual operation. If the FPD's operating mechanism is composed of a total of five axes, two sticks and a pair of lift buttons can be considered. For example, the first stick operates the FPD slide table in the X and Y axes. The second stick operates the Z-axis rotation direction and FPD tilt direction. The pair of lift buttons operates the Z-axis lift. The position and orientation of the FPD are determined by operating the sticks and buttons described above. This position and orientation are stored as coordinates and orientations (vectors) in the object 1 coordinate system. The coordinates and orientations (vectors) are collectively called "coordinates, etc."

[0140] On the other hand, Non-Patent Document 1 states that the distance between the FPD and the patient's body (distance between the subject and the image receiving surface) should be as short as possible, and the numerical value of this distance is determined in advance by the surgeon, etc. Therefore, by providing a measurement sensor such as a vision sensor that measures the distance to the patient's body, the position and orientation of the Z-axis lift can be autonomously controlled. Furthermore, in the case of mechanical force drive, autonomous control can be achieved by activating an up / down switch. Furthermore, in the case of each stick operation, it is preferable to autonomously control the position and orientation to return to the initial position (zero point) before surgery. Furthermore, in the case of mechanical force drive or mechanical force servo drive, autonomous control by pressing a separate button is preferable.

[0141] In the previous section, it was stated that semi-automatic operation with manual operation as the main method for determining the position and orientation of the FPD is preferable. On the other hand, for a synchronous X-ray source, the operation for directly facing the FPD is to determine the position and orientation through autonomous control. This is preferably automatic control driven by mechanical force. If effort is not spared, manual control is also acceptable. In this autonomous control, control information for the FPD coordinates and vectors (orientation of the FPD image receiving surface) based on the item 1 coordinate system is obtained from the FPD position and orientation determination information. This control information is synchronized with the item 2 coordinate system via the reference coordinate system. This method is used to determine the position and orientation of the synchronous X-ray source. This is called the "coordinate vector synchronization method" for synchronous X-ray sources. In addition, we will explain a method for improving the accuracy of the attitude of the synchronous X-ray source (the orientation of the X-ray source's emission direction). This is a method for optimizing the attitude by slightly oscillating the pan and tilt angles of the synchronous X-ray source after determining the position and attitude of the synchronous X-ray source using the coordinate vector synchronization method, and finding the attitude (angle) at which the X-ray intensity received by the FPD is maximized. It is also acceptable to slightly oscillate both the X and Y axes of the X-ray source slide table. This is called the "received light intensity attitude optimization method" for the synchronous X-ray source.

[0142] The object 1 coordinate system and object 2 coordinate system are linked using the reference coordinate system as a reference, and the position and orientation information between these linked coordinate systems is synchronized. By applying the coordinate vector synchronization method and the light receiving intensity orientation optimization method, the position and orientation of the synchronized X-ray source can be determined and controlled based on the position and orientation information of the X-ray receiver. When using the above-mentioned position and orientation determination method, it is not desirable to adjust the height of the patient's body by moving only the FPD storage box on the FPD storage box stand. However, by using the height adjustment knob near the wheels of the FPD storage box stand, it is possible to move the entire FPD storage box stand in the vertical direction at the same time while maintaining the correlation between the X-ray source support stand and the FPD slide table. [Example]

[0143] (Method of using the present invention in interventional cardiology surgery) In Example 10, a method of using the present invention in current IVR surgery was examined. Here, it was confirmed that the present invention can be used without any problems when inserting a catheter into the body during current IVR surgery. First, there is the preparation stage, in which a catheter is inserted into a blood vessel or the body during a medical procedure involving puncture or incision. In many cases, primary X-rays are not emitted from the synchronized X-ray source during the preparation stage. Therefore, during the preparation stage, there is no need to assemble protective equipment and instruments for radiation protection. During the preparation stage, it is confirmed that the separate protective equipment and instruments do not interfere with the operation before assembly. Next, IVR surgery after generating primary X-rays from the synchronous X-ray source requires the assembly of protective equipment and tools for radiation protection. The assembled protective equipment and tools of the present invention were confirmed to be able to cope with this without any problems as follows.

[0144] In the case of cardiac catheterization surgery for vascular interventional radiology, the catheter is inserted into three main arteries: the artery in the groin (femoral artery), the artery in the elbow (cubital artery), and the artery in the wrist (radial artery). On the other hand, non-vascular interventional radiology involves percutaneous needle puncture of ducts such as bile ducts and abscesses under image guidance, followed by the placement of drainage tubes. There are also procedures such as tissue biopsy, in which a thick needle is inserted into a solid organ to extract tissue. Percutaneous abdominal interventions often involve a transrectal incision. To summarize the locations where the catheters mentioned above can be inserted, the groin, elbow, wrist, and left subclavian area require only a puncture and no incision, while the left chest and abdomen require an incision.

[0145] First, consider the case where only puncture is performed and no incision is required. In all protective devices and protective equipment of the present invention, the groin is an exposed area. All protective devices include boxes, etc. All protective equipment includes clothing, blankets, etc. Furthermore, the wrist and elbow areas are exposed by sliding the box body onto the lower limbs on the table. In this area, all protective devices and protective equipment do not interfere with medical procedures during the preparation stage.

[0146] Next, we will consider the case of open surgery. There is an FPD storage box in the left chest area. In open surgery on the left chest, X-ray fluoroscopy using high-intensity primary X-rays may be used. In this case, the closure shielding lid of the square sleeve port on the FPD storage box is closed. After ensuring the same level of shielding as the box body, the arm is inserted through the gloveless port. If open surgery is performed on the abdomen, the process is slightly different from that of the left chest area. In open surgery on the abdomen, the box body is slid toward the lower limbs to expose the abdomen. If the sliding width is insufficient, the FPD storage box can also be slid toward the head by about half its total length.

[0147] There are no problems with the use of the protective devices and instruments of this invention for vascular and non-vascular IVR procedures. Furthermore, in cases involving open surgery, a split box is preferable, with some exceptions. The box body on the lower limb side of the split box is designed to slide onto the table.

[0148] After inserting a catheter into a blood vessel or the body via puncture or incision surgery, the catheter continues to be inserted to reach the affected area. During this process, X-ray fluoroscopy is performed to identify branching points of blood vessels, etc. First, the FPD storage box and the box body are assembled on a table. Next, the surgeon manually moves the X-ray detector (FPD) to a position directly facing the affected area. Alternatively, the X-ray detector (FPD) can be moved semi-automatically using sticks on the machine and in the control room. If the FPD's operating mechanism consists of a total of five axes, there are two sticks and a pair of lift buttons. The first stick operates the FPD slide table in the X and Y axes. The second stick controls the rotation direction of the Z axis and the tilt direction of the FPD. The pair of lift buttons controls the lifting and lowering of the Z axis. The position and orientation of the FPD are determined by operating the sticks and buttons described above.

[0149] Once the position and orientation of the FPD has been determined, the power to the X-ray source is turned on. When the power is turned on, the synchronous X-ray source moves autonomously to a position and orientation that directly faces the FPD. If X-axis tilt images are required in the right anterior oblique direction (RAO) or left anterior oblique direction (LAO), the FPD can be moved manually (semi-automatically) to that position and orientation, and the synchronous X-ray source will then move autonomously to a position and orientation that directly faces the FPD. The irradiation angle for LAO is 60 degrees from the vertical. The standard specifications for RAO and LAO are 60 degrees, but a special specification with a 6-axis FPD movement mechanism makes it possible to reach nearly 90 degrees. When switching between RAO and LAO, the X-axis rail slides.

[0150] When the IVR procedure is completed, the FPD and the synchronous X-ray source return to their initial positions and orientations by autonomous control by pressing the end button. [Explanation of symbols]

[0151] 1. Box 2. Table 3.Table support 4. Box body 5.End box 6. Viewing window 7. Box top 8. Sleeve Port 9. Sleeve 10. X-ray receiver 11. Receiver arm 12.Connection flange 13. Receiver port 14.End surface top plate 15. Irradiation field 16. FPD storage box top plate 17. Additional shield box 18. FPD storage box 19. Box body 20. Patient port 21. Mats etc. 22. Blankets, etc. 23. Blanket holder 24.Connector 25.Patient body 26. Guide rail 30. C-arm 31. Receiver joint 32. Bellows shielding 33.X-ray source 34.Sliding guide 35.FPD slide table 36. Slide Guide 37. FPD storage box stand 38. Height adjustment rotary knob 39. Rack and pinion 40. X-ray receiver (FPD) 41.Portable X-ray source 42. X-ray source stand 43.Sliding plate shielding 45.Box end plate 46. ​​Rail 47. Telescopic arm 48.FPD attitude control board 49.FPD operating mechanism 53. Lead-containing arm sleeve 54. Lead-containing gloves 55. Lead-containing arm cover 56. Lead-containing gloves 60. Globe Sport 61. Slide mechanism 62. FPD Y-axis rail 63.FPD X-axis rail 64. Cart 65. Vertical axis rotation mechanism 66. Thai Band 69. High-performance table 70.Tabletop Steps 71.Absorbent plate 72.Transmission plate unit 73. Spacer 74. Middle Row 75. Sliding Table 76.Aperture plate 77. Table top 78.Slide absorber 79. Hollowed-out section 80. Bottom board step 81. Thin Sheet 82.Low reflection scattering opening / closing plate 83. Mesh 84. Table support 85. Support rail 86. Reinforced beam 87. Hinge mechanism 88. Strip curtains 89.Closed Shielding Cover 90. Wheel 91.Patient port cover 92. Clothes 93. Head Cover 94.Support structure 95.Composite absorbent materials 96.Shielding materials 97. Linear attenuation materials 98. Thick blanket 99. Acrylic additional shield box 100.Synchronous X-ray source 101. X-ray source support stand 102. X-ray source slide table 103. X-ray source 2-axis attitude control board 104. X-ray source X-axis rail 105. X-ray source Y-axis rail 106. X-ray source pan axis 107. X-ray source tilt axis 108. X-ray source rotation mechanism 108. X-ray source rotation mechanism 109.Y-axis feed mechanism 110. Integrated Radiation Exposure Reduction X-ray Fluoroscopy Device 111. FPD Z-axis tilt axis joint 112. Reference point of reference coordinates

Claims

1. In a medical under-tube type X-ray fluoroscopy device, The table supports the patient's body. The X-ray receiver is mechanically separated from the X-ray source under the table. The box with shielding function is placed on top of the table, The X-ray receiver and its operating mechanism are placed inside the box. Both the X-ray source and the X-ray receiver have four or more axes of motion; The pan and tilt axes of the X-ray source and the rotation axis of the X-ray receiver have a range of motion of 120 degrees or more; The operating mechanism of the X-ray source has rails with a path length of at least twice the movable range of the X-ray receiver in both the X-axis, which is perpendicular to the body axis, and the Y-axis, which is the body axis of the X-ray source. An X-ray fluoroscopy device characterized in that the irradiation angle of the X-ray source that can be received by the X-ray receiver is 45 degrees or more from the vertical.

2. 2. The X-ray fluoroscopy apparatus according to claim 1, In the Y-axis movement mechanism located under the table, The Y-axis rail has a partial elliptical arc shape when viewed from the X-axis direction. The length of the major axis of the partial elliptical arc shape is equal to or less than the length of the space under the table, The length of the minor axis is 1.5 times or less the inter-surface distance, which is the distance from the center of the tilt axis of the X-ray source to the image receiving surface of the X-ray receiver, The length of the arc is greater than or equal to one-quarter and less than one-half of the circumference of the ellipse, By arranging the Y-axis rail in the shape of a partial ellipse arc on the Y-axis side of the X-ray source slide table in a downward convex orientation, An X-ray fluoroscopy device characterized in that the range of angles at which the X-ray source can irradiate is increased compared to a straight rail.

3. 2. The X-ray fluoroscopy apparatus according to claim 1, In the X-axis direction movement mechanism of the X-ray source located under the table The X-axis rail has a partial arc shape when viewed from the Y-axis direction. The radius of the circle having the shape of a partial arc is 0.7 times or more and 1.5 times or less the inter-face distance, The length of the arc is greater than or equal to one-quarter and less than one-half of the circumference, The arc-shaped X-axis rail is arranged on the X-axis side of the X-ray source slide table in a downward convex orientation. The X-ray source slides along the X-axis rail. An X-ray fluoroscopy device characterized by increasing the range of irradiation angles compared to a straight rail

4. 2. The X-ray fluoroscopy apparatus according to claim 1, In the X-axis direction, which is perpendicular to the body axis of the X-ray source located under the table, The X-axis rail has a partial arc shape when viewed from the Y-axis direction. The radius of the circle having the shape of a partial arc is 0.7 times or more and 1.5 times or less the inter-face distance, The length of the arc is greater than or equal to one-quarter and less than one-half of the circumference, The arc-shaped X-axis rail is arranged on the X-axis side of the X-ray source slide table in a downward convex orientation. The X-ray source slides along the X-axis rail. X-ray fluoroscopy device characterized by reduced size and area of ​​the area in which the X-ray source operates

5. 5. The X-ray fluoroscopy device according to claim 3 or claim 4. The ceiling of the box is curved upwards to fit the shape of the patient's body lying on their back. The X-axis slide table of the X-ray receiver is placed along the ceiling surface. The X-ray receiver is moved along a curved path by medical personnel, An X-ray fluoroscopy device that allows medical personnel to easily determine the position and orientation of the X-ray receiver so that it faces the affected area.

6. 2. The X-ray fluoroscopy device according to claim 1, The ceiling of the box is curved upwards to match the shape of the upper surface of the patient's body lying on their back. The X-axis slide table of the X-ray receiver is positioned along the ceiling surface. Medical personnel move the X-ray receiver along a curved path on the X-axis slide table. An X-ray fluoroscopy device that allows medical personnel to easily determine the position and orientation of the X-ray receiver so that it faces the affected area.

7. 7. The X-ray fluoroscope according to claim 6, The X-ray receiver is positioned and oriented so that the image surface faces the affected area. The X-ray source is positioned so that it faces the X-ray receiver in a spatially opposite direction. An X-ray fluoroscopy device that can capture precise X-ray transmission images without tilt or distortion within a box.

8. 2. The X-ray fluoroscopy apparatus according to claim 1, A basic coordinate system and its reference point are established, which the X-ray source and the X-ray receiver can always refer to and whose position and orientation do not change over time. The X-ray source and the X-ray receiver each have their own independent object coordinate systems. Both parties communicate position and orientation information to each other via a basic coordinate system, By identifying the position and orientation information of both parties, An X-ray fluoroscopy apparatus characterized in that the position and orientation of the X-ray source and the X-ray receiver can be determined relative to each other

9. The X-ray fluoroscope according to claim 8, The position and orientation information of the X-ray receiver is transmitted to the operating mechanism of the X-ray source via the basic coordinate system, The X-ray source moves autonomously in accordance with changes in the position and orientation of the X-ray receiver. An X-ray fluoroscopy device characterized in that the position and orientation of the X-ray source can be determined so that it is spatially directly opposite the X-ray receiver.

10. 10. The X-ray fluoroscope according to claim 9, After determining the position and orientation of the X-ray source so that it is spatially facing the X-ray receiver, The X-ray source is oscillated by a small dimension or angle by a motion mechanism, The X-ray receiver determines the position and orientation of the X-ray source that maximizes the received image intensity, This position and orientation information is transmitted to the X-ray source operating mechanism, By correcting this position and orientation information and determining a new position and orientation, An X-ray fluoroscopy device that can accurately position and pose the affected area, capturing high-quality images without tilt or distortion.

Images