X-ray diagnosis apparatus, x-ray condition setting method, and program

Abstract

To properly set an X-ray condition.SOLUTION: An X-ray diagnosis apparatus according to an embodiment includes: a collection unit which collects a plurality of X-ray images sequentially from a subject with a medical device inserted into a body of the subject; a determination unit which determines a region including the medical device in the X-ray images; a calculation unit which calculates a degree of the medical device staying in the region based on the plurality of X-ray images, assigns weights to a plurality of pixels included in the region based on the degree, and calculates a parameter related to the region based on the weights and pixel values of the pixels; and a setting unit which sets an X-ray condition based on the parameter.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The embodiments disclosed in this specification and the drawings relate to an X-ray diagnostic apparatus, an X-ray condition setting method, and a program.

Background Art

[0002] There is known a method of setting X-ray conditions called Auto Brightness Control (ABC) control. ABC control is a technique for maintaining the image quality of an X-ray image while reducing the radiation dose to a subject by appropriately adjusting the X-ray conditions according to the brightness of X-ray images collected in the past.

[0003] When adjusting the X-ray conditions according to the brightness of the entire X-ray image, the X-ray conditions are adjusted so that other regions other than the region of interest that the user such as a doctor pays attention to can also be visually recognized. Therefore, it cannot be said that it is optimal as the X-ray conditions for observing the region of interest. Therefore, in ABC control, usually, a Region Of Interest (ROI) is set on the X-ray image, and the X-ray conditions are adjusted according to the brightness within the region of interest. However, there are cases where other regions other than the region of interest are included in the region of interest, and there are also cases where the region of interest moves with respect to the region of interest. Therefore, there are cases where appropriate X-ray conditions cannot be set.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to appropriately set X-ray conditions. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problems. The problems corresponding to the respective effects of the respective configurations shown in the embodiments described later can also be regarded as other problems.

Means for Solving the Problem

[0006] The X-ray diagnostic apparatus according to the embodiment includes: a collection unit that sequentially collects a plurality of X-ray images from a subject with a medical device inserted into the body; a determination unit that determines a region including the medical device in the X-ray image; a calculation unit that calculates the degree to which the medical device has stayed in the region based on the plurality of X-ray images, assigns weights to a plurality of pixels included in the region based on the degree, and calculates a parameter related to the region based on the weight and the pixel value of the pixel; and a setting unit that sets X-ray conditions based on the parameter.

Brief Description of the Drawings

[0007]

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MODE FOR CARRYING OUT THE INVENTION

[0008] Hereinafter, embodiments of an X-ray diagnostic apparatus, an X-ray condition setting method, and a program will be described with reference to the drawings. In the following embodiments, parts denoted by the same reference numerals perform the same operations, and overlapping descriptions will be omitted as appropriate.

[0009] (First Embodiment) In the first embodiment, the X-ray diagnostic apparatus 10 shown in FIG. 1 will be described as an example. FIG. 1 is a block diagram showing an example of the configuration of the X-ray diagnostic apparatus 10 according to the first embodiment. As shown in FIG. 1, the X-ray diagnostic apparatus 10 includes an X-ray high voltage device 101, an X-ray tube 102, an X-ray collimator 103, a top plate 104, a C-arm 105, an X-ray detector 106, an input interface 107, a display 108, a memory 109, and a processing circuit 110.

[0010] The X-ray high voltage device 101 supplies a high voltage to the X-ray tube 102 under the control of the processing circuit 110. For example, the X-ray high voltage device 101 has an electric circuit such as a transformer and a rectifier, and includes a high voltage generator that generates a high voltage applied to the X-ray tube 102, and an X-ray control device that controls the output voltage according to the X-ray irradiated by the X-ray tube 102. Note that the high voltage generator may be of a transformer type or an inverter type.

[0011] The X-ray tube 102 is a vacuum tube having a cathode (filament) that generates thermoelectrons and an anode (target) that generates X-rays upon receiving the collision of thermoelectrons. The X-ray tube 102 generates X-rays by irradiating thermoelectrons from the cathode toward the anode using the high voltage supplied from the X-ray high voltage device 101.

[0012] The X-ray collimator 103 includes a collimator that narrows the irradiation range of the X-rays generated by the X-ray tube 102, and a filter that adjusts the X-rays irradiated from the X-ray tube 102.

[0013] The collimator in the X-ray aperture 103 has, for example, four slidable aperture vanes. The collimator narrows the X-rays generated by the X-ray tube 102 by sliding the aperture vanes and irradiates the subject P. Here, the aperture vanes are plate-like members made of lead or the like, and are provided near the X-ray irradiation port of the X-ray tube 102 to adjust the X-ray irradiation range.

[0014] The filter in the X-ray aperture 103 changes the quality of the X-rays transmitted depending on its material and thickness for the purpose of reducing the radiation dose to the subject P and improving the image quality of the X-ray image, reducing the soft X-ray component that is easily absorbed by the subject P, or reducing the high-energy component that causes a decrease in the contrast of the X-ray image. Further, the filter changes the dose and irradiation range of the X-rays depending on its material, thickness, position, etc., and attenuates the X-rays so that the X-rays irradiated from the X-ray tube 102 to the subject P have a predetermined distribution.

[0015] For example, the X-ray aperture 103 has a drive mechanism such as a motor and an actuator, and controls the X-ray irradiation by operating the drive mechanism under the control of a processing circuit 110 described later. For example, the X-ray aperture 103 adjusts the opening degree of the aperture vanes of the collimator by applying a drive voltage to the drive mechanism according to the control signal received from the processing circuit 110, and controls the irradiation range of the X-rays irradiated to the subject P. Further, for example, the X-ray aperture 103 adjusts the position of the filter by applying a drive voltage to the drive mechanism according to the control signal received from the processing circuit 110, and controls the dose distribution of the X-rays irradiated to the subject P.

[0016] The top plate 104 is a bed on which the subject P is placed, and is arranged on a bed (not shown). Note that the subject P is not included in the X-ray diagnostic apparatus 10. For example, the bed has a drive mechanism such as a motor and an actuator, and controls the movement and tilt of the top plate 104 by operating the drive mechanism under the control of a processing circuit 110 described later. For example, the bed moves or tilts the top plate 104 by applying a drive voltage to the drive mechanism according to the control signal received from the processing circuit 110.

[0017] The C-arm 105 holds the X-ray tube 102 and the X-ray collimator 103 and the X-ray detector 106 so as to face each other with the subject P interposed therebetween. For example, the C-arm 105 has a drive mechanism such as a motor and an actuator, and rotates or moves by operating the drive mechanism under the control of a processing circuit 110 described later. For example, the C-arm 105 adds a drive voltage to the drive mechanism according to a control signal received from the processing circuit 110, thereby rotating and moving the X-ray tube 102 and the X-ray collimator 103 and the X-ray detector 106 with respect to the subject P, and controlling the irradiation position and irradiation angle of the X-rays. Note that, in FIG. 1, the case where the X-ray diagnostic apparatus 10 is a single plane is described as an example, but the embodiment is not limited thereto, and it may be a biplane case.

[0018] The X-ray detector 106 is, for example, an X-ray flat panel detector (FPD) having detection elements arranged in a matrix. The X-ray detector 106 detects X-rays irradiated from the X-ray tube 102 and transmitted through the subject P, and outputs a detection signal corresponding to the detected X-ray dose to the processing circuit 110. Note that the X-ray detector 106 may be an indirect conversion type detector having a grid, a scintillator array, and a photosensor array, or may be a direct conversion type detector having a semiconductor element that converts incident X-rays into an electrical signal.

[0019] The input interface 107 receives various input operations from the user, converts the received input operations into electrical signals, and outputs them to the processing circuit 110. For example, the input interface 107 can be realized by a mouse, a keyboard, a trackball, a switch, a button, a joystick, a touch pad for performing input operations by touching an operation surface, a touch screen in which a display screen and a touch pad are integrated, a non-contact input circuit using an optical sensor, a voice input circuit, etc. Note that the input interface 107 may be composed of a tablet terminal or the like that can communicate wirelessly with the processing circuit 110. Also, the input interface 107 may be a circuit that receives input operations from the user by motion capture. For example, the input interface 107 can receive the body movement and line of sight of the user as input operations by processing signals acquired via a tracker or images collected about the user. Also, the input interface 107 is not limited to those equipped with physical operation components such as a mouse and a keyboard. For example, a circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the X-ray diagnostic apparatus 10 main body and outputs this electrical signal to the X-ray diagnostic apparatus 10 main body is also included in the examples of the input interface 107.

[0020] The display 108 displays various information. For example, the display 108 displays an X-ray image collected from the subject P. Also, for example, the display 108 displays a GUI (Graphical User Interface) for receiving various instructions and settings, etc. from the user via the input interface 107. For example, the display 108 is a liquid crystal display or a CRT (Cathode Ray Tube) display. The display 108 may be a desktop type, or may be composed of a tablet terminal or the like that can communicate wirelessly with the X-ray diagnostic apparatus 10 main body.

[0021] In FIG. 1, the X-ray diagnostic apparatus 10 is described as including a display 108. However, the X-ray diagnostic apparatus 10 may include a projector instead of or in addition to the display 108. The projector can project an image onto a screen, a wall, a floor, the body surface of the subject P, etc. under the control of the processing circuit 110. For example, the projector can also project an image onto an arbitrary plane, object, space, etc. by projection mapping. The display 108 and the projector are examples of a display unit.

[0022] The memory 109 stores various data under the control of the processing circuit 110. For example, the memory 109 stores X-ray images collected from the subject P. Also, for example, the memory 109 stores programs for the circuits included in the X-ray diagnostic apparatus 10 to realize their functions. For example, the memory 109 is realized by a semiconductor memory element such as a RAM (Random Access Memory), a flash memory, a hard disk, an optical disk, etc. Alternatively, the memory 109 may be realized by a server group (cloud) connected to the X-ray diagnostic apparatus 10 via a network.

[0023] The processing circuit 110 controls the operation of the entire X-ray diagnostic apparatus 10 by executing a collection function 110a, a determination function 110b, a calculation function 110c, a setting function 110d, and an output function 110e. The collection function 110a is an example of a collection unit. The determination function 110b is an example of a determination unit. The calculation function 110c is an example of a calculation unit. The setting function 110d is an example of a setting unit. The output function 110e is an example of an output unit.

[0024] For example, by reading and executing a program corresponding to the collection function 110a from the memory 109, the processing circuit 110 performs imaging of the subject P and collects X-ray images. For example, the collection function 110a controls the X-ray high-voltage device 101, adjusts the voltage supplied to the X-ray tube 102, and controls the X-ray dose and on / off irradiated to the subject P. Also, for example, the collection function 110a controls the operations of the X-ray collimator 103, the top plate 104, the C-arm 105, etc., to control the X-ray irradiation range, the distribution of the X-ray dose, the X-ray irradiation angle, etc. Specifically, the collection function 110a controls the operation of the X-ray collimator 103 and adjusts the opening degree of the collimator blades of the collimator to control the X-ray irradiation range irradiated to the subject P. Also, the collection function 110a controls the operation of the X-ray collimator 103 and adjusts the position of the filter to control the distribution of the X-ray dose. Also, the collection function 110a controls the X-ray irradiation range and the irradiation angle by rotating or moving the C-arm 105. Also, the collection function 110a controls the X-ray irradiation range and the irradiation angle by moving or tilting the top plate 104. Also, the collection function 110a generates an X-ray image based on the detection signal received from the X-ray detector 106.

[0025] Here, the collection function 110a can sequentially collect a plurality of X-ray images. In other words, the collection function 110a can collect a plurality of X-ray images over time. For example, the collection function 110a can collect a plurality of X-ray images over time by repeatedly irradiating pulsed X-rays from the X-ray tube 102. For example, the collection function 110a collects a plurality of X-ray images from the subject P over time while a procedure (such as endovascular intervention treatment, etc.) of inserting a medical device into the body of the subject P is being performed.

[0026] The determination function 110b determines the region including the medical device in the X-ray image. The calculation function 110c calculates parameters related to the region based on the position of the medical device in each of the plurality of X-ray images and the pixel values of the plurality of pixels included in the region. The setting function 110d sets the X-ray conditions based on the parameters. The output function 110e causes the display unit to display various information such as the collected X-ray images and the set X-ray conditions. Details of the processing by the determination function 110b, the calculation function 110c, the setting function 110d, and the output function 110e will be described later.

[0027] In the X-ray diagnostic apparatus 10 shown in FIG. 1, each processing function is stored in the memory 109 in the form of a program executable by a computer. The processing circuit 110 is a processor that realizes the functions corresponding to the respective programs by reading and executing the programs from the memory 109. In other words, the processing circuit 110 in the state of having read the program has the functions corresponding to the read program.

[0028] In FIG. 1, the collection function 110a, the determination function 110b, the calculation function 110c, the setting function 110d, and the output function 110e are described as being realized by a single processing circuit 110. However, it is also possible to configure the processing circuit 110 by combining a plurality of independent processors, and each processor realizes the functions by executing programs. Further, each processing function of the processing circuit 110 may be realized by being appropriately distributed or integrated into a single or a plurality of processing circuits.

[0029] Further, the processing circuit 110 may realize the functions by using the processors of external devices connected via a network. For example, the processing circuit 110 reads and executes the programs corresponding to the respective functions from the memory 109, and realizes each function shown in FIG. 1 by using a group of servers connected to the X-ray diagnostic apparatus 10 via a network as calculation resources.

[0030] The configuration example of the X-ray diagnostic apparatus 10 has been described above. With such a configuration, the X-ray diagnostic apparatus 10 can appropriately set X-ray conditions.

[0031] It should be understood that the processes such as "increase" and "make larger" in the following description may be relative. For example, the process of "increasing" the weight assigned to a certain pixel may be a process of changing the weight assigned to the pixel to a larger value, or a process of changing the weight assigned to other pixels to a smaller value, or a combination of these. The same applies to the descriptions such as "decrease" and "make smaller".

[0032] As a technique for appropriately setting X-ray conditions, automatic brightness control (ABC) has been known conventionally. For example, in ABC control, a region of interest (ROI) is set on the X-ray image, and X-ray conditions are set based on the pixel values within the ROI.

[0033] An example of ABC control will be described with reference to FIG. 2. The X-ray image I1 shown in FIG. 2 is an X-ray image collected from a subject P in whom a medical device A1 is inserted into the body. The medical device A1 is, for example, a catheter, a guide wire, or the like inserted into the blood vessel of the subject P in intravascular intervention treatment. Also, in FIG. 2, a circular region R11 is set at the center of the X-ray image I1 as the ROI. The region R11 is, for example, a default ROI with a preset position and shape. Note that for the region R11 shown in FIG. 2, a certain weight is assigned to each pixel within the region R11.

[0034] For example, in ABC control, parameters such as the average value of pixel values are calculated for the pixels included in region R11, and the X-ray conditions are set based on the comparison result of comparing the calculated parameters with a predetermined threshold value. Note that the pixel value used for calculating the parameters in ABC control may be a value (luminance) corresponding to the X-ray dose detected by the X-ray detector 106, or may be a value after arbitrary conversion processing is performed on the luminance. That is, the pixel value is a value assigned to each pixel based on the X-ray detection result by the X-ray detector 106, and does not necessarily have to be the luminance itself.

[0035] The X-ray conditions set in ABC control are, for example, the tube voltage, tube current, irradiation time, etc. of the X-rays irradiated from the X-ray tube 102. For example, when the average value of the luminance of the pixels included in region R11 is lower than the threshold value (that is, when region R11 is dark), the tube voltage is increased to increase the X-ray transmittance, or the tube current and irradiation time are increased to increase the X-ray dose. As a result, in the X-ray image collected after the X-ray image I1, the X-ray conditions are changed so that the average value of the luminance of the pixels included in region R11 becomes higher than the threshold value (that is, region R11 becomes brighter).

[0036] However, the region R11 shown in FIG. 2 does not necessarily coincide with the attention region that the user pays attention to. In many cases, the user pays attention to the position of the tip of the current medical device A1 or the position passed by the tip of the medical device A1 until reaching the current position, and operates the medical device A1. Hereinafter, the position passed by the tip of the medical device A1 until reaching the current position will also be simply referred to as a locus.

[0037] On the other hand, although the region R11 in FIG. 2 is arranged at an appropriate position including the tip of the medical device A1, for example, the positions included in the region R12 do not need to be paid attention to when operating the medical device A1. That is, adjusting the X-ray conditions so that the positions included in the region R12 in the region R11 are also easily visible is not optimal as ABC control for observing the attention region.

[0038] Also, for example, when an interfering object such as the object A2 shown in FIG. 2 is included in the region R11, the X-ray conditions are set so that the interfering object can be easily visually recognized, and the visibility of the target region decreases. This is particularly prominent when the interfering object is a high absorber such as bone, teeth, or a medical device other than the medical device A1. Examples of medical devices other than the medical device A1 include pacemakers, artificial joints, and probes for transesophageal echocardiography (TEE) probes.

[0039] From the above, it is preferable that the ROI is set to match the target region that the user pays attention to, as shown in the region R2 of FIG. 3, for example. The region R2 is an ROI set based on the trajectory of the tip of the medical device A1. Specifically, the region R2 is set by the determination function 110b so as to include the trajectory of the tip of the medical device A1. As shown in FIG. 3, the region R2 does not include interfering objects such as the region R12 and the object A2 shown in FIG. 2. Therefore, by performing ABC control with the region R12 as the ROI, X-ray conditions suitable for visually recognizing the target region can be set.

[0040] Hereinafter, the ABC control performed by the X-ray diagnostic apparatus 10 will be described in more detail with reference to the flowchart of FIG. 4. First, as shown in step S101, the collection of X-ray images is started. After step S101, a plurality of X-ray images are collected over time in parallel with the processes of steps S102 to S106. Alternatively, the processes of steps S102 to S106 may be executed when one or a predetermined number of X-ray images are collected.

[0041] In step S102, the determination function 110b determines the region including the medical device in the X-ray image. That is, in step S102, the determination function 110b sets the ROI so as to include the medical device in the X-ray image. Hereinafter, the region determination process by the determination function 110b will be described with reference to FIGS. 5 to 7. In FIGS. 5 to 7, similar to the region R2 in FIG. 3, an example of setting the ROI based on the trajectory of the tip of the medical device A1 will be described.

[0042] The X-ray images I21, I22, I23, and I24 shown in FIG. 5 are an example of a plurality of X-ray images collected over time. For example, the X-ray images I21 to I24 are images for four consecutive frames or images for four frames extracted at a certain sampling interval from among a plurality of frames of X-ray images.

[0043] More specifically, the X-ray image I21 is an image collected before the medical device A1 reaches the imaging range. Thereafter, while the operation of inserting the medical device A1 is being advanced, the X-ray images I22, I23, and I24 are sequentially collected. The X-ray images I21 to I24 may be collected under X-ray conditions controlled by ABC based on the default ROI shown in FIG. 2 or the like, or may be collected under initial X-ray conditions not controlled by ABC.

[0044] As shown in FIG. 5, the determination function 110b differentiates each of the X-ray images I22, I23, and I24 from the X-ray image I21 as a mask image. The difference image between the X-ray image I22 and the X-ray image I21 is also referred to as the X-ray image I22'. The difference image between the X-ray image I23 and the X-ray image I21 is also referred to as the X-ray image I23'. The difference image between the X-ray image I24 and the X-ray image I21 is also referred to as the X-ray image I24'. In the X-ray images I22', I23', and I24', background components such as bones and organs are removed, and the medical device A1 is emphasized.

[0045] Based on the tip positions of the medical device A1 in the X-ray images I22’, X-ray image I23’, and X-ray image I24’ respectively, the determination function 110b sets the area including the medical device A1. For example, as shown in FIG. 6, the determination function 110b sets an area R23 that includes the tip position in the X-ray image I22’ and the tip position in the X-ray image I23’. For example, the determination function 110b sets an elliptical area with two points, namely the tip position in the X-ray image I22’ and the tip position in the X-ray image I23’, as the foci, as the area R23. As another example, the determination function 110b sets an area that is included within a certain distance from the line segment connecting the tip position in the X-ray image I22’ and the tip position in the X-ray image I23’ as the area R23.

[0046] In the same manner as in FIG. 6, the determination function 110b can set the area including the medical device A1 for the X-ray images of each frame. That is, based on the tip positions of the medical device A1 in each of the plurality of X-ray images, the determination function 110b can sequentially set a plurality of areas as shown in the areas R21 to R26 in FIG. 7. The area obtained by combining the areas R21 to R26 corresponds to the area R2 shown in FIG. 3. That is, by performing ABC control with the area obtained by combining the areas R21 to R26 as the ROI, it becomes possible to set X-ray conditions suitable for visual recognition of the region of interest.

[0047] In FIG. 5, an example was described in which the X-ray image I21 collected before the medical device A1 reaches the imaging range is used as the mask image. However, the mask image can be updated as appropriate. For example, when the X-ray image I22 is used as the mask image, in the difference image between the X-ray image I23 and the X-ray image I24, in addition to background components such as bones and organs, the portion of the medical device A1 that was depicted in the X-ray image I22 is removed. For example, in the difference image between the X-ray image I22 and the X-ray image I23, only the portion of the medical device A1 that is beyond the tip position at the time of collection of the X-ray image I22 is depicted.

[0048] The region determination method shown in FIGS. 5 to 7 is merely an example, and various modifications are possible. For example, when the medical device A1 is a wire-shaped device such as a catheter or a guide wire, the trajectory of the tip of the medical device A1 generally coincides with the shape of the medical device A1. Therefore, the determination function 110b may determine the ROI based on the shape of the medical device A1 depicted in the X-ray image. For example, the determination function 110b may perform image processing such as segmentation processing or image recognition processing on the X-ray images such as the X-ray images I22 to I24 shown in FIG. 5 or the difference image from the mask image to determine the ROI. Note that the image processing may be performed by a learned model (for example, a learned neural network that realizes semantic segmentation).

[0049] Also, the region determination process by the determination function 110b may be performed in units of pixels of the X-ray image, or may be performed in a unit different from pixels. For example, the determination function 110b may set sections composed of a plurality of pixels on the X-ray image in a grid pattern, and determine the region including the medical device A1 using the section as a unit.

[0050] Incidentally, although the ROI set based on the trajectory of the tip of the medical device A1 is the region that the user pays attention to, the degree of attention is not constant within the ROI. For example, the degree of attention of the region closer to the tip of the medical device A1 is higher than that of the base side of the medical device A1.

[0051] Also, the degree of attention of the residence region as shown in FIG. 8 is high. FIG. 8 is a schematic diagram showing the trajectory of the tip of the medical device A1 when an operation of inserting the medical device A1 in the direction of the arrow is performed. The residence region is a region where it becomes difficult to advance the medical device A1 and it takes time to pass through. Regarding the residence region, it often remains the object of attention even after the tip has passed through.

[0052] There are various factors that make it difficult to advance the medical device A1 in the retention area. As an example, the retention area may be a characteristic part of the vascular structure (such as a curved part or a branched part). Such a characteristic part may continue to be noted even after the tip has passed through, for example, so that no burden is imposed on the blood vessel wall when operating the medical device A1.

[0053] As another example, the retention area may be the treatment target site. For example, in interventional treatment for a stenosis of a blood vessel, the tip of the guide wire is passed through the stenosis, and a balloon, a stent, etc. are conveyed along the guide wire to the stenosis. Here, it is assumed that the medical device A1 is a guide wire and it takes time to pass through the stenosis.

[0054] As described above, from the viewpoint that the degree of attention differs for each position, the calculation function 110c sets weights for each pixel (step S103). For example, the calculation function 110c sets a large weight for the pixels near the tip of the medical device A1. Also, for example, the calculation function 110c sets a large weight for the pixels in the retention area. That is, the calculation function 110c calculates the degree to which the medical device A1 has stayed in the area determined in step S102, and based on this degree, assigns weights to a plurality of pixels included in the area.

[0055] Here, an example of a method for calculating the retention area will be described with reference to FIG. 9. FIG. 9 shows an X-ray image I25 collected from the subject P and an X-ray image collected n frames before the X-ray image I25. Here, n is a natural number. That is, the X-ray image collected n frames before the X-ray image I25 may be the X-ray image of the frame immediately before the X-ray image I25, or may be an X-ray image two or more frames before the X-ray image I25. Also, each X-ray image shown in FIG. 9 may be an image obtained by performing differential processing with a mask image, or may be an image without differential processing.

[0056] As shown in FIG. 9, when performing difference processing between the X-ray image I25 and the X-ray image collected n frames before the X-ray image I25, the tip portion of the medical device A1 is extracted. The length of this tip portion corresponds to the movement amount ΔX of the medical device A1 during n frames. The calculation function 110c can specify the retention area based on the movement amount ΔX. For example, when the movement amount ΔX is less than the threshold value, the calculation function 110c specifies the area around the tip portion of the medical device A1 extracted by the difference processing as the retention area.

[0057] The process of calculating the retention area can be rephrased as a process of calculating the degree of stay of the medical device A1 in two ranks of "whether it corresponds to the retention area or not". For example, the area specified as the retention area is an area where the degree of stay of the medical device A1 is higher than the threshold value, and the area not specified as the retention area is an area where the degree of stay of the medical device A1 is lower than the threshold value. Of course, the degree of stay of the medical device A1 can be calculated in three or more ranks or continuously. In this embodiment, as an example, an example of calculating the degree of stay of the medical device A1 in two ranks (whether it corresponds to the retention area or not) will be described.

[0058] Next, another example of the method for calculating the retention area will be described with reference to FIG. 10. FIG. 10 shows the X-ray image I26 of frame f. In the X-ray image I26, the tip position of the medical device A1 at the time of frame f is indicated by "T(f)", the tip position of the medical device A1 at the time of frame (f + 1) is indicated by "T(f + 1)", the tip position of the medical device A1 at the time of frame (f + 2) is indicated by "T(f + 2)", the tip position of the medical device A1 at the time of frame (f + 3) is indicated by "T(f + 3)", and the tip position of the medical device A1 at the time of frame (f + 4) is indicated by "T(f + 4)".

[0059] Further, the calculation function 110c calculates the length of time that the medical device A1 has stayed, using "r" shown in FIG. 10 as a threshold value. That is, the calculation function 110c regards that the medical device A1 stays while the tip position is included in the circle with a radius "r" centered on the tip position "T(f)", and calculates the residence time for the position of "T(f)". For example, in the case shown in FIG. 10, the medical device A1 stays during the period corresponding to two frames from frame f to frame (f + 2). The calculation function 110c compares the number of frames during which the medical device A1 has stayed or the number of seconds obtained by converting the number of frames according to the frame rate with the threshold value, and when the threshold value is exceeded, identifies the area around the tip position "T(f)" as the residence area.

[0060] Then, the calculation function 110c assigns weights to the pixels included in the ROI based on the calculation result of the residence area. In the following description, the ROI to which weights are assigned to each pixel is also referred to as a weighted ROI.

[0061] An example of the process of assigning weights will be described with reference to FIG. 11. The left figure in FIG. 11 shows an X-ray image, and the right figure shows the distribution of weights set for the pixels of the X-ray image in the left figure. The weight distribution in the right figure of FIG. 11 is an example of a weighted ROI. Note that the weights may be assigned for each pixel or for each section composed of a plurality of pixels. In FIG. 11, an example of dividing the X-ray image into 64 sections of "8×8" and assigning weights for each section will be described.

[0062] In FIG. 11, at least a weight of "1" is assigned to the pixels within the ROI, and the weight is set to "0" for the pixels outside the ROI. Note that the ROI in FIG. 11 is an area determined based on the trajectory of the tip of the medical device A1 as shown in FIGS. 5 to 7, for example. As shown in FIG. 11, when the medical device A1 is a wire-shaped device, the ROI determined based on the trajectory has a shape along the medical device A1.

[0063] In addition, for the pixels corresponding to the "tip", the calculation function 110c sets the weight "5" assuming that it is the position that the user pays attention to. Here, the "tip" is the current tip position of the medical device A1.

[0064] In addition, for the pixels corresponding to the "retention area", the calculation function 110c sets the weight "3" assuming that it is the position that the user pays attention to. Here, the "retention area" is the area specified as the retention area in the current or past X-ray image. For example, in the case shown in FIG. 11, although the medical device A1 has already passed through the retention area, the calculation function 110c also sets the weight "3" for the area specified as the retention area in the past.

[0065] The weighting process shown in FIG. 11 is merely an example, and various modifications are possible.

[0066] For example, in endovascular intervention therapy, the calculation function 110c may detect the indwelling device from the X-ray image and set a large weight for the pixel at the position of the indwelling device. For example, when endovascular intervention therapy is performed for the purpose of expanding a stenosis in a blood vessel, a balloon catheter is inserted into the blood vessel of the subject P. The balloon catheter expands the blood vessel by causing the balloon to reach the stenosis and inflate. In addition, the balloon catheter indwells a stent in the stenosis of the blood vessel so that the expanded state of the blood vessel is maintained. When the medical device A1 is a balloon catheter, the calculation function 110c detects the indwelling device such as the balloon or the stent from the X-ray image and sets a large weight for the pixel at the detected position. For example, the calculation function 110c can detect the indwelling device by performing image processing such as pattern matching on the marker attached to the indwelling device or the shape of the indwelling device itself.

[0067] Further, when the position where the calculation function 110c sets a large weight (such as the tip of the medical device A1, the retention region, the indwelling device, etc.) overlaps with a high absorber such as bone, addition may be performed so that the weight becomes larger. Conversely, for the position of the high absorber that does not overlap with the position where the weight is set large within the ROI, the weight may be set small, for example, by setting the weight to "0".

[0068] Further, the calculation function 110c may set a large weight for the pixels in the blood vessel region. The method for calculating the blood vessel region is not particularly limited. As an example, it can be calculated based on the trajectory of the tip of the medical device A1. For example, as shown in FIGS. 5 to 7, when the ROI is set by expanding the positions on the trajectory, the entire ROI does not necessarily correspond to the blood vessel region. However, at least the positions on the trajectory itself can be said to be included in the blood vessel region because the medical device A1 inserted into the blood vessel could be located there. Therefore, the calculation function 110c sets a vicinity region narrower than the ROI in the vicinity of the trajectory, and sets a larger weight for the vicinity region as the blood vessel region than for other positions within the ROI.

[0069] Of course, when an angiogram image is available, the calculation function 110c can identify the blood vessel region based on the angiogram image. For example, the collection function 110a can use the X-ray images collected over time as angiogram images by injecting a contrast agent into the blood vessels of the subject P while collecting a plurality of X-ray images over time. Note that the injection of the contrast agent may be performed by the collection function 110a controlling an injector, or may be performed manually by the user. Also, for example, if a 3D contrast vessel model has been collected in advance, the calculation function 110c can identify the blood vessel region by aligning the X-ray images collected over time by the collection function 110a with the 3D contrast vessel model.

[0070] As an example of a variation of weighting, an example of increasing the weight has been described, but the calculation function 110c may appropriately reduce the weight in consideration of various factors. For example, in FIGS. 5 to 7, an example has been described in which regions R21 to R26 are sequentially set and combined to form an ROI. Here, the region R26 including the tip of the current medical device A1 is a new region set based on the real-time image, whereas the region R21 has been set for some time. Thus, when the elapsed time since the setting varies for each position within the ROI, the calculation function 110c may reduce the weight of the position with a longer elapsed time.

[0071] Also, for example, while the medical device A1 is being operated, its tip is being focused on, so it is preferable to assign a large weight. However, when the operation of the medical device A1 is stopped, the degree of focus decreases. Therefore, the calculation function 110c may reduce the weight applied to the tip of the medical device A1, for example, when the tip of the medical device A1 does not move for a certain period of time.

[0072] After weights are assigned to a plurality of pixels included in the ROI, the calculation function 110c calculates a parameter related to the ROI based on the assigned weights and the pixel values (step S104). For example, the calculation function 110c calculates a weighted average value by the following formula (1) as a parameter related to the ROI. In formula (1), pixels with a weight of "0" may be excluded from the calculation of formula (1).

[0073]

Equation

[0074] The subscript i in formula (1) is an argument indicating a pixel. Also, in formula (1), ROI is the region in the X-ray image excluding the pixels with the weight of "0" set. Note that for the pixels outside the ROI, in addition to setting the weight of "0", the pixels inside the ROI may also have the weight of "0" set. The wi in formula (1) is the weight (weighting coefficient) assigned to the i-th pixel. Also, the pi in formula (1) is the pixel value of the i-th pixel.

[0075] Note that in formula (1), an example of calculating the average value as a parameter related to the ROI has been described, but the specific examples of the parameters are not limited to this. For example, the calculation function 110c may calculate statistical values other than the average value as parameters, or may calculate other values such as CNR (Contrast-to-Noise Ratio).

[0076] Also, so far, as shown in FIG. 3 and FIG. 7 for example, an example of setting an ROI in the shape along the trajectory of the tip of the medical device A1 has been described, but the embodiments are not limited to this. For example, the determination function 110b may set a circular region similar to FIG. 2 as the ROI. Even in such a case, by setting the weight of the pixels at positions away from the trajectory of the tip of the medical device A1 (for example, the pixels in the region R12) in the circular region to "0", the weighted ROI will have the same content, so values similar to those when using the ROI in FIG. 3 and FIG. 7 are calculated as the parameters related to the ROI.

[0077] The setting function 110d sets the X-ray conditions based on the parameters calculated by the calculation function 110c (step S105). For example, the setting function 110d compares the parameters with a threshold value and sets the X-ray conditions based on the comparison result. The threshold value is, for example, pre-stored in the memory 109. The threshold value may be appropriately set, changed, or adjusted according to a user instruction via the input interface 107. For example, the setting function 110d adjusts at least one of the tube voltage, the tube current, and the product of the X-ray irradiation time (tube current-time product mAs) based on the comparison result between the parameter and the threshold value. That is, the setting function 110d executes ABC control based on the parameters related to the ROI.

[0078] When the X-ray conditions are set in step S105, the collection function 110a performs the collection of subsequent X-ray images according to the newly set X-ray conditions. Further, the processing circuit 110 determines whether or not the collection of the X-ray image is completed (step S106), and if so (step S106 affirmative), ends the processing. On the other hand, if not completed (step S106 negative), the processing circuit 110 returns to step S102 again.

[0079] When returning to step S102 again, the determination function 110b determines the ROI again. For example, after performing the processing of steps S102 to S106 with the region obtained by combining the regions R21 to R26 shown in FIG. 7 as the ROI and then returning to step S102 again, it is assumed that the position of the tip of the medical device A1 in the newly collected X-ray image has advanced further than the position shown in FIG. 7. In this case, the determination function 110b can set a region based on the position of the tip of the medical device A1 in the newly collected X-ray image, combine it with the regions R21 to R26, and use it as a new ROI.

[0080] Regarding the ROI, it can also be reset as appropriate. That is, even a position once determined to be included in the ROI may become less worthy of attention over time and may no longer be suitable to be included in the ROI. For example, when an instruction to reset the ROI is received from the user, the determination function 110b does not update the existing ROI but determines a new ROI. For example, the determination function 110b sets a new ROI based on the trajectory of the tip of the medical device A1 that appears in the X-ray images for a predetermined number of frames including the newly collected X-ray image.

[0081] The output function 110e may appropriately display the ROI determined by the determination function 110b. For example, each time a new X-ray image is collected by the collection function 110a, the output function 110e sequentially displays it on the display 108. That is, the output function 110e performs real-time display of the X-ray image. Further, the output function 110e superimposes and displays the ROI on the X-ray image being displayed in real time.

[0082] For example, the output function 110e displays the ROI at regular time intervals (e.g., every minute). By superimposing and displaying the ROI on the X-ray image being displayed in real time, it becomes easier to recognize what kind of ROI is set, but it may interfere with the visual recognition of the X-ray image. By performing the display of the ROI at regular time intervals, the output function 110e can ensure the visibility of the X-ray image while making it easy for the user to recognize the ROI. Also, for example, when the change in the ROI is small since the previous display (e.g., when there is no difference of 10% or more), the output function 110e may omit the display of the ROI. Alternatively, the output function 110e may display the ROI only when there is a change in the ROI above a threshold value.

[0083] Examples of the display of the ROI are shown in FIGS. 12 and 13. In FIG. 12, the ROI is indicated by a dashed line, and the residence area is indicated by a solid line. According to the display in FIG. 12, the user can grasp the range of the set ROI and that a particularly large weight is given to the residence area. Further, in FIG. 13, the ROI is indicated by a solid line, and the magnitude of the weight given to the pixels at each position is indicated in color. That is, in FIG. 13, the weighted ROI is displayed. According to the display in FIG. 13, the user can grasp the distribution of the weights given to each position along with the range of the set ROI.

[0084] For example, when the user is not paying attention to the residence area in FIG. 12 or when the weight distribution in FIG. 13 does not conform to the user's wishes, the user can instruct a change in the ROI. For example, the output function 110e causes the UI (User Interface) shown in FIG. 14 to be displayed on the display 108. The user can instruct a change in the ROI by operating the UI in FIG. 14 via the input interface 107.

[0085] For example, when "Standard ROI" shown in the UI of FIG. 14 is selected, the determination function 110b determines, as a new ROI, the default ROI shown in FIG. 2, for example. That is, when "Standard ROI" is selected, ABC control is executed based on a predetermined area. Further, when "RESET" shown in the UI of FIG. 14 is selected, the determination function 110b performs the reset of the ROI described above. That is, when "RESET" is selected, the determination function 110b does not update the existing ROI but performs a process of determining a new ROI.

[0086] Also, when "ABC ROI ON / OFF" shown in the UI of FIG. 14 is selected, the output function 110e switches the display / non-display of the ROI shown in FIGS. 12 and 13. Also, when "Device Display" shown in the UI of FIG. 14 is selected, the output function 110e highlights the medical device A1. Also, when "Tip Position Display" shown in the UI of FIG. 14 is selected, the output function 110e highlights the tip of the medical device A1.

[0087] Note that when the "Standard ROI" in FIG. 14 is selected or the like, by switching the ROI, the X-ray conditions set by the ABC control may change significantly, and the appearance of the displayed image (such as brightness and contrast) may change suddenly. In order to prevent such a sudden change in the appearance of the image, the determination function 110b may perform the switching of the ROI step by step as shown in FIG. 15, for example.

[0088] As described above, the processing circuit 110 can execute ABC control based on the region including the medical device A1. For example, the determination function 110b determines the region obtained by combining the regions R21 to R26 shown in FIG. 7 as the ROI. Also, the calculation function 110c calculates the degree to which the medical device A1 has stayed in the ROI. For example, the calculation function 110c specifies the staying region in the ROI. Next, the calculation function 110c assigns weights to a plurality of pixels included in the ROI based on the degree to which the medical device A1 has stayed, and calculates a parameter related to the ROI based on the assigned weights and the pixel values. Then, the setting function 110d executes ABC control based on the parameter related to the ROI. A mode including assigning weights to a plurality of pixels included in the ROI based on the degree to which the medical device A1 has stayed in the ROI is also referred to as a staying degree mode.

[0089] In addition, the processing circuit 110 can also execute ABC control based on a predetermined region (standard ROI). For example, the determination function 110b determines the circular region R11 shown in FIG. 2 as the ROI. Further, the calculation function 110c calculates a parameter related to the region R11 based on the pixel values of a plurality of pixels included in the circular region R11. For example, the calculation function 110c calculates a statistical value of the pixel values of the pixels included in the region R11 as a parameter related to the region R11. Note that the specific example of the statistical value is not particularly limited, but as an example, an average value or a median value can be mentioned. Then, the setting function 110d executes ABC control based on the parameter related to the circular region R11. The mode of executing ABC control with a predetermined region as the ROI is also described as the standard mode.

[0090] Regarding the region including the medical device A1 determined as the ROI in the residence mode, it is also described as the first region. For example, the region obtained by combining the regions R21 to R26 shown in FIG. 7 is an example of the first region. Further, regarding the predetermined region determined as the ROI in the standard mode, it is also described as the second region. For example, the circular region R11 shown in FIG. 2 is an example of the second region.

[0091] The residence mode and the standard mode can be switched as appropriate. For example, when the "standard ROI" in FIG. 14 is selected while ABC control is being executed in the residence mode, the determination function 110b switches to ABC control in the standard mode.

[0092] Of course, the determination function 110b may switch from the standard mode to the residence degree mode. For example, immediately after the start of X-ray image collection or when "RESET" shown in FIG. 14 is selected, the determination function 110b first sets the standard mode and gradually switches to the residence degree mode as the X-ray image collection progresses. Also, for example, when "Standard ROI" in FIG. 14 is selected while ABC control is being executed in the standard mode, the processing circuit 110 may switch to ABC control in the residence degree mode. Alternatively, an icon for switching from the standard mode to the residence degree mode may be further displayed in the UI of FIG. 14.

[0093] When switching between the residence degree mode and the standard mode, the determination function 110b may gradually change the shape between the first region and the second region. For example, when switching from the residence degree mode to the standard mode, the determination function 110b gradually changes the shape of the ROI so that the shape gradually approaches the standard ROI from the region including the medical device A1 as shown in FIG. 15. For example, the determination function 110b gradually changes the shape of the ROI step by step each time one or a predetermined number of X-ray images are newly collected. Similarly, when switching from the standard mode to the residence degree mode, the determination function 110b may gradually change the shape of the ROI so that the shape gradually approaches the region including the medical device A1 from the standard ROI.

[0094] As described above, the collection function 110a according to the first embodiment sequentially collects a plurality of X-ray images from the subject P into whom the medical device A1 has been inserted into the body. Also, the determination function 110b determines an ROI including the medical device in the X-ray image. Also, the calculation function 110c calculates the degree to which the medical device A1 has resided in the ROI based on a plurality of X-ray images, assigns weights to a plurality of pixels included in the ROI based on the calculated degree, and based on the assigned weights and the pixel values, calculates a parameter related to the ROI. Also, the setting function 110d sets X-ray conditions based on the parameter related to the ROI. With such a configuration, the X-ray diagnostic apparatus 10 according to the first embodiment can appropriately set the X-ray conditions.

[0095] For example, the calculation function 110c identifies a residence area based on the position of the tip of the medical device A1 in each of a plurality of X-ray images, and sets a weighted ROI so as to assign a large weight to the pixels included in the residence area. The X-ray diagnostic apparatus 10 can execute ABC control so that the visibility of the residence area is improved according to such a weighted ROI. Furthermore, by improving the visibility of a region of interest such as the residence area, it becomes possible to smoothly operate the medical device A1, and as a result, it is possible to shorten the procedure time and reduce the radiation dose of the subject P.

[0096] (Second Embodiment) In the first embodiment, an example in which an area including the medical device A1 is determined as an ROI has been described. In the second embodiment, an example in which a second area is determined by performing a processing operation on the first area, and various processing operations such as calculation of parameters are executed using the processed second area as an ROI will be described. Hereinafter, parts overlapping with the description of the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

[0097] For example, the determination function 110b performs the above-described processing operation based on the residence area. For example, first, in the same manner as in the cases of FIGS. 5 to 7, the determination function 110b sets a plurality of areas indicated by dotted lines in FIG. 16. The plurality of areas indicated by dotted lines in FIG. 16 are an example of the first area. Also, the calculation function 110c identifies a residence area based on the position of the tip of the medical device A1 in each of a plurality of X-ray images.

[0098] Here, the determination function 110b expands an area that overlaps with the residence area among the plurality of areas indicated by dotted lines in FIG. 16, and determines the expanded area as an ROI. Such an expanded ROI is an example of the second area. Thereby, ABC control can be executed so that the visibility is improved including the periphery of the residence area. Note that when a high absorber such as bone is located around the residence area, the determination function 110b may not perform the expansion in order to avoid the high absorber being included in the ROI and affecting the ABC control.

[0099] As another example, the determination function 110b performs the above-described processing based on a change in the relative position or angle between the X-ray tube 102 or the X-ray detector 106 and the subject P. For example, when the top plate 104 is translated (panned), the subject P is also translated, and the relative position with respect to the X-ray tube 102 and the X-ray detector 106 changes. In this case, the determination function 110b can perform the processing of the ROI based on the X-ray images before and after the top plate 104 is translated, and determine the processed ROI as a new ROI. For example, the determination function 110b aligns the positions of background components such as bones between the X-ray images before and after the top plate 104 is translated, calculates the shift amount, and uniformly shifts the ROI.

[0100] In addition, the X-ray detector 106 may be movable or rotatable on a plane parallel to the detection surface. In this case, since the amount of movement or rotation of the X-ray detector 106 is a known value controlled by the collection function 110a, the determination function 110b can calculate the shift amount of the ROI by general image processing calculations (such as affine transformation) and perform the processing of the ROI.

[0101] In addition, by the operation of the C-arm 105, the X-ray tube 102 and the X-ray detector 106 rotate relative to the subject P. The determination function 110b pseudo-follows the three-dimensional change of the ROI based on the direction and amount of rotation of the C-arm 105, and changes the shape and position of the ROI, as shown in FIGS. 17 and 18, for example. The method for calculating the three-dimensional change of the ROI is not particularly limited and can be realized by general image conversion processing. Note that cases where the three-dimensional change of the ROI cannot be followed are assumed, such as when the amount of rotation of the C-arm 105 is large or when the region of interest including the medical device A1 or the like moves out of the X-ray irradiation range due to the rotation of the C-arm 105. In this case, the determination function 110b can set a predetermined second region (for example, the default ROI shown in FIG. 2). That is, when it becomes difficult to continue the ABC control in the dwell mode, the determination function 110b can switch to the standard mode.

[0102] (Third Embodiment) In FIG. 15, an example of switching between the dwell mode and the standard mode was described. However, the embodiment is not limited to this, and switching between various other modes is also possible. In the third embodiment, various modes executable in the X-ray diagnostic apparatus 10 and a method of switching between the modes will be described. Hereinafter, parts overlapping with the descriptions of the first and second embodiments will be denoted by the same reference numerals and the descriptions will be omitted.

[0103] An example of a mode executable other than the dwell mode and the standard mode is the tip priority mode. In the case of the tip priority mode, the determination function 110b determines the ROI so as to include the tip of the medical device A1. Further, the calculation function 110c assigns the largest weight to the vicinity of the tip of the medical device A1, or assigns a weight only to the vicinity of the tip of the medical device A1, and calculates a parameter related to the ROI based on the assigned weight and the pixel value. Then, the setting function 110d executes the ABC control based on the parameter related to the ROI.

[0104] By executing the ABC control in the tip priority mode, the visibility of the tip position of the medical device A1 is improved. However, in the tip priority mode, since the degree of dwell of the medical device A1 is not taken into account, the visibility of the dwell area is reduced. For example, the determination function 110b can accept from the user a switch between the tip priority mode and the dwell mode, or a switch between the tip priority mode and the standard mode, via the same UI as in FIG. 14. Alternatively, when it becomes difficult to continue the ABC control in the dwell mode due to rotation of the C-arm 105 or the like, the determination function 110b may automatically switch to the tip priority mode.

[0105] In addition, examples of mode switching between the residence degree mode, the standard mode, and the tip priority mode have been described so far. However, these modes can be further subdivided into a plurality of modes. For example, a plurality of types of residence degree modes may be provided, and the determination function 110b may switch between these plurality of residence degree modes.

[0106] For example, as described in the first embodiment, the calculation function 110c can assign weights to a plurality of pixels included in the ROI so as to reduce the weight of a position where the elapsed time since the determination of the ROI is long. That is, the calculation function 110c can execute a residence degree mode considering the elapsed time. On the contrary, the calculation function 110c can also assign weights to a plurality of pixels included in the ROI based on the degree to which the medical device A1 has stayed without considering the elapsed time since the determination of the ROI. Therefore, the determination function 110b may switch between a residence degree mode considering the elapsed time and a residence degree mode not considering the elapsed time based on, for example, an input operation received from the user.

[0107] The residence degree mode considering the elapsed time will be described with reference to FIG. 19. FIG. 19 is a diagram showing an example of the residence degree mode according to the third embodiment. In FIG. 19, X-ray images I31, I32, I33, and I34 sequentially collected are illustrated. In addition, the tip positions of the medical device A1 are illustrated with crosses in each of the X-ray images I31 to I34.

[0108] In FIG. 19, at time T11, regions R31 and R32 are determined as the ROI. Regions R31 and R32 are determined based on a plurality of X-ray images including the X-ray image I31. For example, at a time point before time T11, region R31 is determined based on one or a plurality of X-ray images. Also, at time T11, region R32 is determined based on the X-ray image I31 or a plurality of X-ray images including the X-ray image I31.

[0109] In addition, the ROI determined at time T11 is the combined region of region R31 and region R32. In FIG. 19, region R31 and region R32 overlap. The overlapping region may be included in the newer region R32 or in the previously determined region R31. Also, if one of the two overlapping regions is a retention region, the overlapping region may be included in the retention region.

[0110] In FIG. 19, at time T12, region R33 is added to the ROI. Region R33 may be determined based only on the X-ray image I32 or based on a plurality of X-ray images including the X-ray image I32. The ROI determined at time T12 is the combined region of region R31, region R32, and region R33.

[0111] Similarly, in FIG. 19, at time T13, region R34 and region R35 are added to the ROI. Also, at time T14, region R36, region R37, and region R38 are added to the ROI. At time T14, the ROI is the combined region of regions R31 to R38. Also, as a result of calculating the degree of stay of the medical device A1, region R33, region R35, and region R38 are specified as retention regions.

[0112] For example, the calculation function 110c first assigns weights to each pixel based on the degree of stay of the medical device A1. The weighting process at time T14 in FIG. 19 will be described as an example. The calculation function 110c performs weighting in the same manner as in the case shown in FIG. 11, for example. That is, for the pixels in regions R33, R35, and R38, which are retention regions, the calculation function 110c assigns a weight of "3" assuming that they are positions that the user pays attention to. Alternatively, for the pixels in region R38, since they include the tip of the medical device A1, a weight of "5" may be assigned. Also, the calculation function 110c assigns a weight of "1" to the pixels within the ROI excluding regions R33, R35, and R38. Note that a weight of "0" is assigned to the pixels outside the ROI.

[0113] Furthermore, the calculation function 110c corrects the weight assigned to each pixel based on the degree of residence of the medical device A1, based on the elapsed time since the determination of the ROI. In FIG. 19, it is described assuming that the region R31 was first determined as the ROI, and then the regions R32, R33, R34, R35, R36, R37, and R38 were sequentially determined as the ROI. That is, at time T14, the region R38 is a new region with the shortest elapsed time since it was determined as the ROI. In this case, the calculation function 110c corrects the weight assigned to the pixels in each region so as to increase the weight of the pixels included in the region R38.

[0114] Hereinafter, the weight assigned to each pixel based on the degree of residence of the medical device A1 is described as the weight before correction. The weight before correction is assigned in the same manner as in the case shown in FIG. 11, for example. Also, the weight corrected based on the elapsed time since each region was determined is described as the weight after correction.

[0115] For example, the calculation function 110c calculates the weight after correction by multiplying the weight before correction by a coefficient corresponding to the elapsed time. For example, at time T14, for the region R38 which is the newest and has the shortest elapsed time, the coefficient "1" is assigned. Also, for regions other than the region R38, the calculation function 110c assigns coefficients such that they are less than "1" and closer to "0" as the elapsed time is longer. For example, for the region R37 determined immediately before the region R38, a coefficient close to "1" is assigned. Also, for the region R31 determined first, a coefficient close to "0" is assigned. As a result, the weight after correction is calculated so as to be larger as the degree of residence is higher and larger as the elapsed time is shorter.

[0116] Then, the calculation function 110c calculates a parameter related to the ROI based on the weight after correction assigned to each pixel and the pixel value of each pixel. Also, the setting function 110d executes ABC control based on the parameter related to the ROI.

[0117] In the residence degree mode shown in FIG. 19, ABC control is executed so that the residence area and the current or most recent position of the medical device A1 can be visually recognized in a well-balanced manner. For example, in the case shown in FIG. 19, ABC control is executed with the highest priority given to the visibility of the area R38 that includes the current position of the medical device A1 and is also the residence area. Further, if the area R38 were not the residence area, ABC control would be executed so that both the area R38 that includes the current position of the medical device A1 and the other residence areas (area R33, area R35) could be visually recognized in a well-balanced manner.

[0118] Another example of the residence degree mode considering the elapsed time will be described with reference to FIG. 20. FIG. 20 is a diagram showing an example of the residence degree mode according to the third embodiment. In FIG. 20, X-ray images I41, I42, I43, and I44 sequentially collected are illustrated. Further, the tip position of the medical device A1 is illustrated with a cross mark in each of the X-ray images I41 to I44.

[0119] In FIG. 20, at time T21, areas R41, R42, and R43 are determined as the ROI. Similar to the case of FIG. 19, the areas R41, R42, and R43 are determined based on a plurality of X-ray images including the X-ray image I41. For example, at a time point before time T21, the area R41 is determined based on one or more X-ray images, then the area R42 is determined based on one or more X-ray images collected next, and at time T21, the area R43 is determined based on the X-ray image I41 or a plurality of X-ray images including the X-ray image I41. The ROI determined at time T21 is the combined area of the areas R41, R42, and R43. Further, in FIG. 20, at time T22, areas R44, R45, R46, R47, and R48 are added to the ROI.

[0120] The ROI determined at time T22 is the combined area of regions R41 to R48. Also, as a result of calculating the degree of stay of medical device A1, regions R43, R45, and R48 are identified as the stay regions. The calculation function 110c assigns weights to the pixels included in the ROI in the same manner as in the case shown in FIG. 11, for example. That is, the calculation function 110c assigns a weight of "3" to the pixels in regions R43, R45, and R48, which are the stay regions, assuming that they are the positions that the user pays attention to. Alternatively, for the pixels in region R48, since the tip of medical device A1 is included, a weight of "5" may be assigned. Also, the calculation function 110c assigns a weight of "1" to the pixels within the ROI excluding regions R43, R45, and R48. Note that a weight of "0" is assigned to the pixels outside the ROI.

[0121] In FIG. 20, the calculation function 110c sequentially reduces the weight assigned to the aging stay regions. For example, the calculation function 110c compares the elapsed time since each stay region such as regions R43, R45, and R48 was determined in the ROI with a threshold value at each time point such as time T23 and time T24. Then, the calculation function 110c reduces the weight assigned to the stay regions whose elapsed time exceeds the threshold value.

[0122] Among the residence areas shown in FIG. 20, as the ROI, area R43 is first determined, then area R45 is determined, and finally area R48 is determined. Therefore, at time T23, only area R43 has had a time equal to or greater than the threshold pass since it was determined as the ROI. Thus, the calculation function 110c assigns the same weight to the pixels within area R43 as to the pixels within the ROI excluding the residence area after time T23. For example, if the calculation function 110c assigned a weight of "3" to the pixels within area R43 at time T22, then after time T23, it assigns a weight of "1" to the pixels within area R43. Note that the weight "3" is an example of the first weight assigned to the pixels of the residence area. Also, the weight "1" is an example of the second weight assigned to the pixels within the ROI excluding the residence area. That is, the calculation function 110c assigns the first weight to the pixels of the residence area where the degree of residence of the medical device A1 is high, assigns the second weight to the pixels within the ROI excluding the residence area, and when the elapsed time since being determined as the ROI exceeds the threshold, replaces the weight assigned to the pixels of the residence area with the second weight.

[0123] Similarly, at time T24, a time equal to or greater than the threshold has passed since area R45 was determined as the ROI. Thus, the calculation function 110c assigns the same weight to the pixels within area R45 as to the pixels within the ROI excluding the residence area after time T24. That is, the calculation function 110c resets the weighting as the residence area in descending order of age after a certain time has passed.

[0124] In the residence degree mode shown in FIG. 20, basically, ABC control is executed so as to improve the visibility of the residence area. However, for old residence areas whose elapsed time since being determined as the ROI exceeds the threshold, the priority is decreased as the degree of attention decreases. Here, depending on the procedure situation, there may be cases where a large number of residence areas are specified. If a large weight is given to all of these many residence areas, the visibility of other areas of interest such as the tip of the medical device A1 may decrease. On the other hand, in the residence degree mode shown in FIG. 20, since the weight given to old residence areas whose elapsed time exceeds the threshold is decreased, the visibility of other areas of interest can also be ensured.

[0125] Note that the calculation function 110c may hold the information that the area R43 is a residence area even after the time T23. Similarly, the calculation function 110c may hold the information that the area R45 is a residence area even after the time T24. Then, for example, in response to an input operation from the user, the control may be switched so as to appropriately weight the area R43 and the area R45 as residence areas.

[0126] For example, in FIG. 20, at the time of time T24, only the area R48 is given a large weight as a residence area. For example, a weight of "3" is given to the pixels of the area R48, and a weight of "1" is given to the pixels within the ROI other than the area R48. That is, at the time of time T24, the ABC control is executed with the highest priority on the visibility of the area R48, which is the only residence area whose elapsed time since being determined as the ROI does not exceed the threshold. Here, when the user wants to confirm other residence areas as well, the calculation function 110c can increase the weight given to the pixels of the area R45 as in the case of the image I43 in FIG. 20, or increase the weight given to the pixels of the areas R43 and R45 as in the case of the image I42.

[0127] In FIGS. 19 and 20, the residence mode considering the elapsed time since the determination of the ROI was described. Next, with reference to FIG. 21, the residence mode considering the ROI area will be described. FIG. 21 is a diagram showing an example of the residence mode according to the third embodiment. In FIG. 21, the sequentially collected X-ray images I51, X-ray images I52, and X-ray images I53 are illustrated. Also, for each of the X-ray images I51 to I53, the tip position of the medical device A1 is illustrated with a cross mark.

[0128] In FIG. 21, at the time point of time T31, the binding region Rc11 is determined as the ROI. Also, at the time point of time T32, the binding region Rc12 is determined as the ROI. Also, in FIG. 21, an upper limit value is provided for the ROI area. The upper limit value of the ROI area is set, for example, as a ratio to the area of the X-ray image. For example, the upper limit value is set as "30% of the image area". The upper limit value may be arbitrarily adjusted by the user.

[0129] Here, for example, when the ROI area reaches the upper limit value at the time point of time T32, but it is necessary to expand the ROI because the medical device A1 has gone outside the range of the existing ROI, the determination function 110b deletes the ROI from the older one so that the ROI area does not exceed the upper limit value. For example, at time T33, the determination function 110b can determine the binding region Rc13 whose ROI area does not exceed the upper limit value as the ROI by excluding the region Rd corresponding to the old ROI determined before time T31. That is, the determination function 110b determines the ROI by combining the newly determined regions among the plurality of regions determined from the sequentially collected X-ray images so that the ROI area does not exceed the upper limit value.

[0130] If there is no upper limit set for the ROI area, depending on the procedure situation, it is assumed that the ROI may gradually expand and occupy most of the image. In this case, an average X-ray condition will be set so that most of the image can be generally visible, and the visibility of the region of interest will not be improved much. On the other hand, in the residence degree mode shown in FIG. 21, it is possible to prevent the ROI from becoming excessively large and improve the visibility of particularly noticeable regions such as the tip position of the medical device A1 and the new residence region.

[0131] Note that also in FIG. 21, ABC control is executed based on the degree to which the medical device A1 has stayed. For example, the calculation function 110c assigns weights to a plurality of pixels included in the ROI in the same manner as in the case shown in FIG. 11. At this time, the calculation function 110c may reduce the weight given to the pixels at positions where the elapsed time since the ROI was set is long, similar to the cases shown in FIGS. 19 and 20. Alternatively, the calculation function 110c may calculate parameters related to the ROI based on the weights assigned based on the degree to which the medical device A1 has stayed without considering the elapsed time since the ROI was set.

[0132] That is, the residence degree mode considering the elapsed time shown in FIGS. 19 and 20 and the residence degree mode considering the ROI area shown in FIG. 21 can be provided as separate modes or combined into one mode. For example, four residence degree modes can be provided: a residence degree mode considering the elapsed time and the ROI area, a residence degree mode considering the elapsed time and not considering the ROI area, a residence degree mode not considering the elapsed time and considering the ROI area, and a residence degree mode not considering the elapsed time and the ROI area, and it may be configured such that these four residence degree modes can be switched according to user operations or the like.

[0133] Also, the calculation function 110c may retain the information that the region Rd has been included in the ROI even after the time T33. Then, for example, in response to an input operation from the user, the control may be switched appropriately so that the region Rd is included in the ROI.

[0134] As described above, the X-ray diagnostic apparatus 10 can execute the ABC control in various modes. For example, as described with reference to FIGS. 19 and 20, the X-ray diagnostic apparatus 10 can execute the ABC control in the retention degree mode considering the elapsed time since the ROI was determined. Also, as described with reference to FIG. 21, the X-ray diagnostic apparatus 10 can execute the ABC control in the retention degree mode considering the ROI area. Further, the X-ray diagnostic apparatus 10 can execute the ABC control in the retention degree mode considering the elapsed time since the ROI was determined and the ROI area. Also, the X-ray diagnostic apparatus 10 can execute the ABC control in the retention degree mode without considering the elapsed time since the ROI was determined and the ROI area. In addition, the X-ray diagnostic apparatus 10 can also execute the ABC control in modes other than the retention degree mode, such as the tip priority mode and the standard mode. The determination function 110b can receive an operation for switching these modes from the user via the input interface 107. By providing a plurality of modes and appropriately switching them, it becomes possible to more appropriately set the X-ray conditions.

[0135] The determination function 110b can switch the mode based on the operation received from the user, or can automatically switch the mode under predetermined conditions. Hereinafter, an example of automatic mode switching will be described with reference to FIG. 22. FIG. 22 is a diagram showing an example of mode switching according to the third embodiment. In FIG. 22, X-ray images I61, I62, I63, and I64 sequentially collected are illustrated. Also, the tip position of the medical device A1 is illustrated with a cross mark in each of the X-ray images I61 to I64. In FIG. 22, at the time point of time T41, the combined region Rc21 is determined as the ROI. Also, at the time point of time T42, the combined region Rc22 is determined as the ROI.

[0136] In FIG. 22, at the time point of time T43 as well, the combined region Rc22 is determined as the ROI. That is, during the period from time T42 to time T43, the tip of the medical device A1 does not exit the ROI, and the size of the ROI does not change.

[0137] As a case where the size of the ROI does not change, it is conceivable that the tip of the current medical device A1 is located at a difficult point where it is particularly difficult to advance the medical device A1 or at the treatment target site. However, in any case, it is preferable to switch the mode so as to improve the visibility of the tip of the medical device A1. Therefore, for example, when the amount of change in the size of the ROI is equal to or less than the threshold value for a period exceeding the threshold value, the determination function 110b automatically switches to a mode in which the visibility of the tip of the medical device A1 is improved.

[0138] An example of a mode in which the visibility of the tip of the medical device A1 is improved is the tip priority mode. For example, after time T44, the determination function 110b switches to the tip priority mode and determines the ROI so as to include the current position of the tip of the medical device A1.

[0139] For example, the determination function 110b determines only the region Rt11 including the tip of the medical device A1 among the plurality of regions shown in the X-ray image I64 as the ROI. Alternatively, the determination function 110b may determine a circular region or the like within a predetermined distance from the tip position of the medical device A1 as the ROI. Further, the calculation function 110c calculates a statistical value of the pixel values of the pixels included in the ROI as a parameter related to the ROI, and the setting function 110d executes ABC control based on the parameter related to the ROI. Thereby, the ABC control is executed so that the visibility of the tip of the medical device A1 is given top priority.

[0140] As another example, the determination function 110b determines the region obtained by combining a plurality of regions shown in the X-ray image I64 as the ROI. In this case, the ROI includes the region Rt11 including the tip of the medical device A1 and a plurality of regions indicated by the dashed line in the X-ray image I64. Such an ROI may continue to use the ROI that has been used until time T43, or may be newly determined along the shape of the medical device A1. Further, the calculation function 110c assigns weights to each pixel in the ROI so that the weight of the tip position of the medical device A1 becomes the largest. For example, the calculation function 110c assigns weights to each pixel in the ROI so that the smaller the distance from the tip of the medical device A1, the larger the weight. Then, the calculation function 110c calculates a parameter related to the ROI based on the assigned weight and the pixel value, and the setting function 110d executes ABC control based on the parameter related to the ROI. Thereby, the ABC control is executed so as to improve the visibility of the tip and its vicinity of the medical device A1.

[0141] Examples of the mode in which the visibility of the tip of the medical device A1 is improved also include a part of the retention mode. For example, as shown in FIG. 11, when a weight of "5" is assigned to the pixels in the region including the tip, a weight of "3" is assigned to the pixels in the retention region, and a weight of "1" is assigned to the other pixels in the ROI, the visibility of the tip is improved while it is in the retention mode.

[0142] In addition, examples of modes that improve the visibility of the tip of the medical device A1 include the retention degree mode considering the elapsed time, which was described with reference to FIGS. 19 and 20. This is because, although it depends on the surgical situation, regions with a short elapsed time since being determined in the ROI are often regions close to the tip of the medical device A1. Specifically, when there is no situation where the medical device A1 retreats to the root side or returns after passing through a branch portion and advances to another branch destination, and the medical device A1 is simply moving forward, the regions with a short elapsed time since being determined in the ROI coincide with the regions close to the tip of the medical device A1. Therefore, for example, when the retention degree mode that does not consider the elapsed time is set, the determination function 110b may automatically switch to the retention degree mode considering the elapsed time when the amount of change in the size of the ROI is equal to or less than the threshold value for a period exceeding the threshold value.

[0143] Note that the calculation function 110c may also hold the ROI up to time T43, the calculation results of the degree of retention, etc. even after time T44. Thereby, for example, after switching to the tip priority mode at the time of time T44, it is possible to switch back to the retention degree mode in response to an input operation from the user or the like.

[0144] Also, as another case where the ROI does not change, the case where the operation of the medical device A1 is stopped is also conceivable. In this case, rather, it is preferable to reduce the weight applied to the tip of the medical device A1 and enhance the visibility of regions other than the medical device A1.

[0145] When the operation of the medical device A1 is stopped, the tip position of the medical device A1 stops moving. On the other hand, when the medical device A1 is located at a difficult section or a treatment target site, as shown in FIG. 22, it is assumed that the tip position of the medical device A1 moves finely within the ROI. Therefore, the determination function 110b may automatically switch to a mode in which the visibility of the tip of the medical device A1 is improved when the ROI does not change and the tip position of the medical device A1 is moving. For example, the determination function 110b may automatically switch to a mode in which the visibility of the tip of the medical device A1 is improved when the amount of change in the size of the ROI is equal to or less than a threshold value for a period exceeding the threshold value and the amount of movement of the tip of the medical device A1 exceeds the threshold value.

[0146] So far, the method of mode switching has been described with reference to FIG. 22. However, the series of processes shown in FIG. 22 itself can also be regarded as a kind of residence degree mode. That is, the above-described embodiment described with reference to FIG. 22 can be rephrased as a mode in which the weight of pixels close to the tip of the medical device A1 is increased when the ROI does not change. Such a mode is also described as a residence degree mode considering the amount of change in the ROI area.

[0147] When the residence degree mode considering the amount of change in the ROI area is set, the calculation function 110c first calculates the degree to which the medical device A1 has stayed in the ROI, and based on the degree, assigns weights to a plurality of pixels included in the ROI. Then, when the amount of change in the size of the ROI is equal to or less than a threshold value for a period exceeding the threshold value, the calculation function 110c increases the weight of pixels close to the tip of the medical device A1. For example, when the calculation function 110c assigns a weight of "3" to the pixels in the residence area and a weight of "1" to the pixels in the ROI outside the residence area, and the amount of change in the size of the ROI is equal to or less than a threshold value for a period exceeding the threshold value, the weight of the pixels in the area including the tip of the medical device A1 is changed to "5". Further, for example, when the amount of change in the size of the ROI is equal to or less than a threshold value for a period exceeding the threshold value, the calculation function 110c assigns weights to the pixels included in the ROI based on the elapsed time since the ROI was determined.

[0148] (Fourth Embodiment) In addition to the first to third embodiments described above, various modifications may be made and implemented.

[0149] For example, in the above-described embodiments, an example was described in which, based on the position of the tip of the medical device A1 in each of a plurality of X-ray images, a residence area that took time for the medical device A1 to pass through was specified, and pixels within the ROI were weighted based on the residence area. That is, in the above-described embodiments, an example was described in which the degree of residence of the medical device A1 was evaluated in two ranks (whether or not it corresponded to the residence area). However, the method for evaluating the degree of residence of the medical device A1 is not limited to this.

[0150] For example, the calculation function 110c may set ranks of three or more levels indicating the degree of residence of the medical device A1, specify to which rank each pixel within the ROI is classified based on the position of the tip of the medical device A1 in each of a plurality of X-ray images, and weight each pixel based on the specified rank. Also, for example, the calculation function 110c may calculate a value indicating the degree of residence of the medical device A1 for each pixel within the ROI based on the position of the tip of the medical device A1 in each of a plurality of X-ray images, and weight each pixel based on the calculated value. Such a value can be calculated based on, for example, the movement amount ΔX described in FIG. 9 or the residence time described in FIG. 10.

[0151] Also, in the above-described embodiments, an example was described in which various processes such as determination of the ROI and weighting were performed based on the position of the tip of the medical device A1. However, the embodiment is not limited to this, and it is also possible to similarly execute the above-described various processes based on a position other than the tip of the medical device A1. For example, the calculation function 110c can calculate parameters related to the ROI based on the position of a marker attached to a part other than the tip of the medical device A1 and the pixel values of a plurality of pixels included in the ROI in each of a plurality of X-ray images.

[0152] In addition, in the above-described embodiments, an example has been described in which various processes such as determination of the ROI and assignment of weights are performed based on the position of the wire-shaped medical device A1. However, the embodiments are not limited to this, and it is also possible to similarly execute the above-described various processes based on the position of a non-wire-shaped medical device. For example, the calculation function 110c can calculate parameters related to the ROI based on the positions of the markers attached to the stent and the pixel values of the plurality of pixels included in the ROI in each of the plurality of X-ray images.

[0153] In addition, in the above-described embodiments, an example has been described in which a continuous single region is set as the ROI. However, the embodiments are not limited to this, and a plurality of separated regions may be set as the ROI.

[0154] For example, as shown in FIG. 23, there may be a case where a user pays attention to a plurality of non-connected blood vessel regions on the X-ray image I7. In this case, the determination function 110b determines the regions R51 and R52 set for each blood vessel region as the ROI. At this time, the calculation function 110c may change the weight for each region. For example, in the case shown in FIG. 23, since the medical device A3 is inserted into the blood vessel region where the region R52 is set, the calculation function 110c may set a larger weight for the pixels in the region R52 than for the pixels in the region R51.

[0155] In addition, in the above-described embodiments, as an example of the X-ray diagnostic apparatus 10, a C-arm type apparatus that holds the X-ray tube 102 and the X-ray collimator 103 by the C-arm 105 has been illustrated. However, the embodiments are not limited to this. For example, the X-ray tube 102 may be held by a mechanism different from the C-arm 105, such as an arm capable of traveling on a rail provided on the ceiling. In addition, as long as it is possible to collect a plurality of X-ray images from the subject over time, any modification is possible for the specific configuration of the X-ray diagnostic apparatus 10.

[0156] In the above-described embodiment, an example has been described in which various functions such as the determination function 110b, the calculation function 110c, and the setting function 110d are executed in the processing circuit 110 included in the X-ray diagnostic apparatus 10. However, the embodiment is not limited to this. That is, the above-described X-ray condition setting method may be realized in an apparatus different from the X-ray diagnostic apparatus 10. For example, a processing circuit included in an information processing apparatus connected to the X-ray diagnostic apparatus 10 via a network may execute functions corresponding to the determination function 110b, the calculation function 110c, and the setting function 110d to set X-ray conditions.

[0157] For example, the X-ray diagnostic apparatus 10 sequentially collects a plurality of X-ray images over time from a subject P in which a medical device is inserted into the body, and sequentially transmits the collected X-ray images to the information processing apparatus via a network. The information processing apparatus determines a region including the medical device in the received X-ray image, similarly to the determination function 110b. Further, the information processing apparatus calculates a parameter related to the region based on the position of the medical device in each of the plurality of X-ray images and the pixel values of a plurality of pixels included in the determined region, similarly to the calculation function 110c. Further, the information processing apparatus sets X-ray conditions based on the parameter, similarly to the setting function 110d. Then, the information processing apparatus transmits the set X-ray conditions to the X-ray diagnostic apparatus 10 via a network. Thereby, the X-ray diagnostic apparatus 10 can continue to collect X-ray images under appropriate X-ray conditions set by the information processing apparatus.

[0158] The network in the above-described embodiment may be configured by a closed local network within a hospital or a network via the Internet. For example, the information processing apparatus that executes the above-described X-ray condition setting method may be installed within the same facility as the X-ray diagnostic apparatus 10 or in a different facility.

[0159] The term "processor" used in the above description means a circuit such as a CPU, GPU (Graphics PROCESSING Unit), ASIC, programmable logic device (e.g., Simple Programmable Logic Device (SPLD), Complex Programmable Logic Device (CPLD), and Field Programmable Gate Array (FPGA)). When the processor is, for example, a CPU, the processor realizes its function by reading and executing a program stored in a storage circuit. On the other hand, when the processor is, for example, an ASIC, instead of storing a program in a storage circuit, the function is directly incorporated as a logic circuit in the processor's circuit. Note that each processor in the embodiment is not limited to being configured as a single circuit for each processor, and a plurality of independent circuits may be combined to form one processor to realize its function. Further, a plurality of components in each figure may be integrated into one processor to realize its function.

[0160] Each component of each device according to the above-described embodiment is conceptually functional and does not necessarily have to be physically configured as shown in the figure. That is, the specific form of distribution and integration of each device is not limited to that shown in the figure, and all or part of it can be functionally or physically distributed and integrated in any unit according to various loads, usage situations, etc. Further, each processing function performed by each device can be realized in whole or in any part by a CPU and a program analyzed and executed by the CPU, or can be realized as hardware by wired logic.

[0161] In addition, the X-ray condition setting method described in the above-described embodiment can be realized by executing a medical information processing program prepared in advance on a computer such as a personal computer or a workstation. This medical information processing program can be distributed via a network such as the Internet. Further, this medical information processing program is recorded on a non-transitory recording medium readable by a computer such as a hard disk, a flexible disk (FD), a CD-ROM, an MO, a DVD, etc., and can also be executed by being read from the recording medium by the computer.

[0162] According to at least one of the embodiments described above, X-ray conditions can be appropriately set.

[0163] Regarding the above embodiments, the following supplementary notes are disclosed as one aspect and selective features of the invention. (Supplementary Note 1) A collection unit that sequentially collects a plurality of X-ray images from a subject with a medical device inserted into the body, A determination unit that determines a region including the medical device in the X-ray image, Based on a plurality of the X-ray images, calculates the degree to which the medical device has stayed in the region, assigns weights to a plurality of pixels included in the region based on the degree, and based on the weights and the pixel values of the pixels, calculates a parameter regarding the region, a calculation unit, A setting unit that sets X-ray conditions based on the parameter An X-ray diagnostic apparatus comprising: (Supplementary Note 2) The calculation unit may obtain the amount of movement of the medical device between a plurality of the X-ray images based on the positions of the medical device in each of the plurality of X-ray images, and evaluate the degree based on the amount of movement. (Supplementary Note 3) The calculation unit may obtain the length of time the medical device has stayed based on the positions of the medical device in each of the plurality of X-ray images, and evaluate the degree based on the length of time. (Supplementary Note 4) The calculation unit may calculate a parameter related to the region based on the position of the tip of the medical device and the pixel value in each of the plurality of X-ray images. (Supplementary Note 5) The calculation unit may calculate a parameter related to the region based on the position of the marker attached to the medical device and the pixel value in each of the plurality of X-ray images. (Supplementary Note 6) The calculation unit may assign the weight based on the degree and the elapsed time since the region was determined, and increase the weight of the pixels close to the tip of the medical device when the amount of change in the size of the region is equal to or less than a threshold value for a period exceeding the threshold value. (Supplementary Note 7) When switching between a residence degree mode in which a first region including the medical device in the X-ray image is determined as the region, the degree of residence of the medical device in the first region is calculated, weights are assigned to a plurality of pixels included in the first region based on the degree, a parameter is calculated based on the weights and the pixel values of the pixels, and the X-ray conditions are set based on the parameter, and a standard mode in which a parameter related to a second region is calculated based on the pixel values of a plurality of pixels included in a predetermined second region and the X-ray conditions are set based on the parameter, the determination unit may gradually change the shape between the first region and the second region. (Supplementary Note 8) The calculation unit assigns a first weight to the pixels in the residence region with a high degree, assigns a second weight smaller than the first weight to the pixels in the region excluding the residence region, and may replace the weight assigned to the pixels in the residence region with the second weight when the elapsed time since the region was determined exceeds a threshold value. (Supplementary Note 9) The determination unit may determine the region by combining a plurality of newly determined regions among a plurality of regions determined from sequentially acquired X-ray images so that the area of the region does not exceed an upper limit value. (Supplementary Note 10) The determination unit may receive an input operation from a user for switching between a plurality of modes including a residence degree mode that includes assigning the weight to a plurality of pixels included in the region based on the degree. (Appendix 11) When the amount of change in the size of the region is equal to or less than a threshold value for a period exceeding the threshold value, the determination unit may switch to a mode in which the visibility of the tip of the medical device is improved. (Appendix 12) The determination unit determines the second region by performing a processing on the first region, The calculation unit may calculate the parameter based on the position of the medical device in each of the plurality of X-ray images and the pixel values of the plurality of pixels included in the second region. (Appendix 13) The apparatus may further include an output unit that causes the display unit to display the region. (Appendix 14) The output unit may sequentially display the newly collected X-ray images on the display unit, and may superimpose and display the region on the X-ray images at regular time intervals. (Appendix 15) Determine a region including the medical device in a plurality of X-ray images sequentially collected from a subject into which a medical device has been inserted into the body, Based on the plurality of X-ray images, calculate the degree to which the medical device has stayed in the region, assign weights to a plurality of pixels included in the region based on the degree, and calculate a parameter related to the region based on the weights and the pixel values of the pixels, Set X-ray conditions based on the parameter An X-ray condition setting method, including this. (Appendix 16) Determine a region including the medical device in a plurality of X-ray images sequentially collected from a subject into which a medical device has been inserted into the body, Based on the plurality of X-ray images, calculate the degree to which the medical device has stayed in the region, assign weights to a plurality of pixels included in the region based on the degree, and calculate a parameter related to the region based on the weight and the pixel value of the pixel. Set X-ray conditions based on the parameter A program that causes a computer to execute each process.

[0164] Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations of embodiments can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalent scope.

Explanation of Reference Numerals

[0165] 10: X-ray diagnostic apparatus 110: Processing circuit 110a: Collection function 110b: Determination function 110c: Calculation function 110d: Setting function 110e: Output function

Claims

1. An acquisition unit that sequentially acquires a plurality of X-ray images from a subject into whom a medical device has been inserted; A determination unit that determines a region including the medical device in the X-ray image; Based on a plurality of the X-ray images, calculates a degree to which the medical device has stayed in the region, assigns weights to a plurality of pixels included in the region based on the degree, and based on the weights and the pixel values of the pixels, calculates a parameter related to the region; a calculation unit; A setting unit that sets X-ray conditions based on the parameter An X-ray diagnostic apparatus comprising:

2. The calculation unit obtains a movement amount of the medical device between a plurality of the X-ray images based on positions of the medical device in each of the plurality of X-ray images, and evaluates the degree based on the movement amount. The X-ray diagnostic apparatus according to claim 1.

3. The calculation unit obtains a length of time during which the medical device has stayed based on positions of the medical device in each of the plurality of X-ray images, and evaluates the degree based on the length of time. The X-ray diagnostic apparatus according to claim 1.

4. The calculation unit calculates a parameter related to the region based on positions of tips of the medical device in each of the plurality of X-ray images and the pixel values. The X-ray diagnostic apparatus according to claim 1.

5. The calculation unit calculates a parameter related to the region based on positions of markers attached to the medical device in each of the plurality of X-ray images and the pixel values. The X-ray diagnostic apparatus according to claim 1.

6. The calculation unit assigns the weight based on the degree and an elapsed time since the region was determined, and when a change amount of the size of the region is equal to or less than a threshold value for a period exceeding the threshold value, increases the weight of pixels closer to the tip of the medical device. The X-ray diagnostic apparatus according to claim 1.

7. Determine a first region including the medical device in the X-ray image as the region, calculate the degree to which the medical device has stayed in the first region, assign the weight to a plurality of pixels included in the first region based on the degree, calculate the parameter based on the weight and the pixel value of the pixel, and set the X-ray condition based on the parameter; and when switching between the retention degree mode and the standard mode in which a parameter related to the second region is calculated based on the pixel values of a plurality of pixels included in a predetermined second region and the X-ray condition is set based on the parameter, the determination unit gradually changes the shape between the first region and the second region. The X-ray diagnostic apparatus according to claim 1.

8. The calculation unit assigns a first weight to pixels in a retention region where the degree is high, assigns a second weight smaller than the first weight to pixels in the region excluding the retention region, and when the elapsed time since the region was determined exceeds a threshold value, replaces the weight assigned to the pixels in the retention region with the second weight. The X-ray diagnostic apparatus according to claim 1.

9. The determination unit determines the region by combining newly determined regions among a plurality of regions determined from sequentially acquired X-ray images so that the area of the region does not exceed an upper limit value. The X-ray diagnostic apparatus according to claim 1.

10. The determination unit receives an input operation from a user for switching modes among a plurality of modes including a retention degree mode including assigning the weight to a plurality of pixels included in the region based on the degree. The X-ray diagnostic apparatus according to claim 1.

11. When the change amount of the size of the region is equal to or less than a threshold value for a period exceeding the threshold value, the determination unit switches to a mode in which the visibility of the tip of the medical device is improved. The X-ray diagnostic apparatus according to claim 10.

12. The determination unit determines the second region by performing a processing operation on the first region. The calculation unit calculates the parameter based on the position of the medical device in each of the plurality of X-ray images and the pixel values of a plurality of pixels included in the second region. The X-ray diagnostic apparatus according to claim 1.

13. The X-ray diagnostic apparatus according to claim 1, further comprising an output unit that causes the region to be displayed on a display unit.

14. The output unit causes the display unit to sequentially display the newly collected X-ray images, and superimposes and displays the region on the X-ray images at regular time intervals. The X-ray diagnostic apparatus according to claim 13.

15. Determine a region including the medical device in a plurality of X-ray images sequentially collected from a subject into which a medical device has been inserted into the body. Based on the plurality of X-ray images, calculate the degree to which the medical device has remained in the region, assign weights to a plurality of pixels included in the region based on the degree, and based on the weights and the pixel values of the pixels, calculate a parameter related to the region. Set X-ray conditions based on the parameter. An X-ray condition setting method including this.

16. Determine a region including the medical device in a plurality of X-ray images sequentially collected from a subject into which a medical device has been inserted into the body. Based on the plurality of X-ray images, calculate the degree to which the medical device has remained in the region, assign weights to a plurality of pixels included in the region based on the degree, and based on the weights and the pixel values of the pixels, calculate a parameter related to the region. Set X-ray conditions based on the parameter. A program that causes a computer to execute each process.

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