Holding device for holding medical image phantoms

Abstract

A holding device for a medical imaging device, particularly a positron emission tomography (PET) scanning device (1), is provided. The holding device (3) performs the function of holding a medical imaging phantom (2) in a specific position within the detector ring (11) of the medical imaging device. The holding device (3) is configured to be attached to the axial end faces (113, 114) of the detector ring (111). Furthermore, a phantom unit comprising such a holding device (3) and a medical imaging phantom (2), as well as a method for ensuring quality standards of the medical imaging device (1) and / or calibrating the medical imaging device (1), are also provided.

Description

Technical Field

[0001] The present invention relates to a holding device for holding a medical image phantom in a medical imaging device such as a positron emission tomography (PET) scanner. A medical image phantom is often used in the medical imaging field for the purpose of ensuring quality standards and / or calibrating a medical imaging device.

Background Art

[0002] Medical imaging devices such as positron emission tomography (PET) scanners, magnetic resonance imaging (MRI) systems, and computed tomography (CT) devices need to be calibrated regularly to ensure and maintain image quality. Also, it is necessary to verify the quality standards of each medical imaging device from time to time to ensure that the quality of the generated images (which are mainly used for diagnostic purposes but also for other purposes) is sufficient.

[0003] To ensure quality standards and / or calibrate a medical imaging device, a medical image phantom having known specifications is usually placed inside the detector ring of the medical imaging device and scanned according to specific scan settings and scan procedures set for these purposes. Also, medical image phantoms are often used in testing medical imaging devices in research and development activities.

[0004] For example, Patent Document 1 discloses a medical image phantom including a hollow cylindrical case having a removable carrier for accommodating a radiation source.

[0005] Patent Document 2 discloses a quality assurance device as a motion phantom for calibration and accuracy testing of a motion-synchronized CT system.

[0006] A holding device is typically provided to position a medical image phantom in a desired location within the detector ring of a medical imaging device. This holding device holds the medical image phantom in a specific position relative to the detector ring, for example, during calibration and / or quality measurements. For this purpose, the holding device can be directly attached to the detector ring.

[0007] For example, Patent Document 3 discloses a configuration in which multiple radiation source loaders used for calibrating a PET / CT system are directly attached to the radial inner surface of a PET detector ring. Each radiation source loader is equipped with a holding device for connecting its respective radiation source pins to the inner surface of the detector ring.

[0008] The configuration in which the radiation source is directly attached to the inner surface of the detector ring has certain advantages in terms of the precision, accuracy, and reproducibility of the placement of each radiation source relative to the detector ring. On the other hand, in this configuration, it is necessary to place a holding device for the radiation source inside the detector ring, i.e., within the area where imaging is normally performed, which may adversely affect the measurement data. Furthermore, the work of attaching the radiation source, which functions as a medical image phantom, to the radial inner surface of the detector ring can be cumbersome for the operator, and as a result, if the medical image phantom is placed in the wrong position, for example, measurement errors may occur.

[0009] Patent Document 4 discloses a medical image phantom that can be attached to a movable table of a PET / CT combined system. This table is originally intended for placing the patient to be scanned, but with the medical image phantom attached, it can be moved into the opening of the detector ring.

[0010] Patent Document 5 discloses a mounting block for clamping and holding a CT phantom or MRI phantom. This mounting block is thought to be configured to be placed on the movable table of a scanner.

[0011] Patent document 6 discloses another phantom that is placed on a movable table and used for aligning magnetic resonance images with PET images.

[0012] Patent Document 7 discloses a medical image phantom for a CT scanner, which is held by supports positioned in front of and behind the CT gantry.

[0013] Patent Document 8 discloses a phantom holder for supporting a cylindrical phantom positioned along the longitudinal central axis of a CT scanner. This phantom holder is attached to a support structure that supports a detector ring.

[0014] One problem with mounting a medical image phantom to a support structure separate from the patient table or detector ring is that, compared to mounting the phantom directly to the detector ring, the position and orientation of the phantom relative to the detector ring cannot generally be precisely, accurately, and reproducibly defined. In particular, in medical imaging devices where the detector ring is displaceable and / or rotatable relative to the structure to which the phantom is attached, there is an inherent risk that some degree of deviation in the position and / or orientation of the phantom relative to the detector ring will occur during measurement. However, depending on the phantom and / or application, it is often extremely important to accurately and reproducibly position the medical image phantom within the detector ring of the medical imaging device in order to guarantee the validity of the measurement data. [Prior art documents] [Patent Documents]

[0015] [Patent Document 1] U.S. Patent No. 4,499,375 [Patent Document 2] U.S. Patent No. 7,699,522 [Patent Document 3] U.S. Patent Application Publication No. 2008 / 0217541 [Patent Document 4] Japanese Patent Publication No. 2008-011922

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Summary of the Invention

Problems to be Solved by the Invention

[0016] An object of the present invention is to provide a holding device for holding a medical image phantom, which is easy to use and enables accurate and reproducible positioning of the phantom on a medical imaging device.

Means for Solving the Problems

[0017] The above object is achieved by the holding device of the medical imaging device according to claim 1. Further, a phantom unit provided with such a holding device (3) is described in claim 10. Further, a method for ensuring the quality standard of a medical imaging device and / or calibrating a medical imaging device is described in claim 13. Preferred embodiments are described in the dependent claims.

[0018] The holding device is configured to be attached to the axial end face of the detector ring.

[0019] By attaching the holding device to the axial end face of the detector ring, regardless of whether the detector ring is displaced and / or rotated relative to the support structure of the medical imaging device, the position and orientation of the phantom with respect to the detector ring can be defined with high precision, accurately, and reproducibly. Further, by attaching the holding device to the axial end face rather than, for example, the radially inner surface of the detector ring, the holding device, or at least most of it, can be arranged outside the imaging region. Thereby, the influence of the holding device on the imaging result can be minimized. Further, attaching the holding device to the axial end face is usually much easier for an operator than attaching it to the radially inner surface of the detector ring. Therefore, according to such a holding device, positioning the phantom on the medical imaging device can be performed particularly easily, accurately, and reproducibly.

[0020] Therefore, the holding device serves to attach the medical imaging phantom to the medical imaging device, particularly to the detector ring of the medical imaging device. For example, when the phantom is arranged in a predetermined manner within the detector ring for a test or calibration scan, it is preferable that only the holding device functions as an element that physically connects the phantom to the medical imaging device. In a preferred embodiment, the holding device is connected only to one axial end face of the detector ring. However, in other embodiments, a configuration in which the holding device includes a first part and a second part, the first part functions to attach the phantom to the first axial end face of the detector ring, and the second part functions to attach the phantom to the second axial end face of the detector ring is also conceivable.

[0021] In use, it is preferable that the holding device is arranged entirely or mostly outside the detector ring, and in an advantageous aspect, it is preferably arranged outside the imaging region. Thereby, the influence of the holding device on the imaging result can be minimized.

[0022] The holding device is preferably configured to be detachably attached to the detector ring, and in an advantageous embodiment, it is preferable that the holding device is configured so that no tools are required when attaching or detaching it from the detector ring. This greatly simplifies procedures for the device operator, for example, when performing quality assurance and / or calibration scans. Furthermore, the holding device is preferably configured to be detachably attached to the medical image phantom, and in an advantageous embodiment, it is preferable that the holding device is configured so that no tools are required when attaching or detaching it from the medical image phantom. This allows the phantom to be stored separately from the holding device, and allows the same holding device to be used for multiple different phantoms.

[0023] The medical imaging device is preferably a positron emission tomography (PET) scanner, but may be a magnetic resonance imaging (MRI) system, a computed tomography (CT) scanner, or any other device configured to perform medical imaging. In a particularly preferred embodiment, the medical imaging device is configured to acquire images of the brain in particular, for example, the brain of a human or animal, and the patient being imaged during the brain scan procedure is preferably a living organism. Therefore, the medical imaging device can be a brain PET scanner in particular. For this purpose, the detector ring of the medical imaging device is preferably 220 to 300 mm in inner diameter, more preferably 240 to 280 mm, and particularly preferably about 260 mm. Of course, a medical imaging device specifically configured to perform a brain PET scan can usually also be used for other applications (e.g., scanning human limbs, or scanning animals or plants).

[0024] The detector ring of a medical imaging device serves the function of acquiring imaging data during the scanning procedure. During the scanning procedure, the area of ​​the patient to be scanned is usually positioned radially inward of the detector ring. It is preferable that the detector ring is closed along the circumferential direction. By having a closed ring shape, the sensor or sensor module for acquiring imaging data can be optimally positioned along the entire inner surface of the detector ring. Furthermore, by having a closed ring shape, the sensitivity of the detector can be maximized.

[0025] The detector ring preferably comprises multiple sensor modules, where these sensor modules typically all have the same structure and all face radially inward. In an advantageous embodiment, these sensor modules are arranged adjacent to one another along the circumference of the detector ring.

[0026] The inner surface is typically formed by the housing of the detector ring that contains the sensor module. Therefore, this inner surface serves to separate the main inner opening of the detector ring, and in the case of a brain scanner, the patient's head, from the sensor module.

[0027] Therefore, the detector ring typically comprises a substantially cylindrical housing having a radially inner surface and a radially outer surface, as well as a first axial end face and a second axial end face. The retaining device is preferably configured to be attached to the first and / or second axial end faces of the housing. In a preferred embodiment, the retaining device is configured to be attached to only one axial end face of the detector ring. In other embodiments, the retaining device may also be configured to be attached to the second end face and / or the radially inner surface and / or radially outer surface of the detector ring.

[0028] In the most preferred embodiment, the detector ring has a substantially cylindrical shape overall, but in other embodiments, the detector ring as a whole may have a polygonal shape, such as a square or an octagon. In this case, it is preferable that the radial inner surface and radial outer surface of the detector ring define the inner circumference and outer circumference of the polygon of the detector ring, particularly the square or octagon, respectively.

[0029] A medical imaging device may have a main support structure to which a detector is attached. The detector ring can be attached to the main support structure in such a way that it can be translated along, for example, a guide rail of the main support structure. Furthermore, it is preferable that the detector ring is rotatable and / or translated relative to the main support structure of the medical imaging device. In this case, during the imaging procedure, the patient can remain in a seated or supine position, and the detector ring can be positioned optimally relative to the patient (fine-position adjustment) without moving the patient. During normal use of the medical imaging device, the main support structure usually bears the primary weight, if not the entire weight, of the detector ring. Therefore, the main support structure usually functions to support and hold the detector ring in a stable position during the scanning procedure.

[0030] The holding device is preferably configured to hold the medical image phantom so that it penetrates the center of the detector ring and extends particularly along the longitudinal principal axis of the detector ring. The center of the detector ring is usually the geometric center of the radial inner surface of the detector ring.

[0031] In a particularly preferred embodiment, the retaining device comprises a plurality, particularly three, radially extending legs, each configured to be attached to the axial end face of the detector ring. Preferably, all legs extend radially and are located in a common plane. Therefore, it is preferable that the legs are not inclined relative to one another. This allows the retaining device to be realized as an overall flat configuration. By making the retaining device an overall flat configuration, not only is space saving particularly possible, but when attached to the detector ring in a predetermined manner, the retaining device usually does not protrude into the inner space of the detector ring. Preferably, the radially extending legs are connected to each other at the center of the retaining device. Here, it is preferable that the center coincides with the longitudinal principal axis of the detector ring. Preferably, the length from the center of the retaining device to the free end of each radially extending leg is the same for each leg. Preferably, the phantom is attached to or can be attached to the retaining device at the center of the retaining device, and in an advantageous embodiment, it is preferable that it extends parallel to or coincides with the longitudinal principal axis of the detector ring.

[0032] The radially extending legs of the holding device can also be arranged at a constant angular interval from one another. However, an embodiment in which the holding device as a whole is Y-shaped is preferred. In this case, three radially extending legs are provided, and the angular interval between the first leg and the second leg is smaller than the angular interval between the third leg and the first and second legs, respectively. In this embodiment, it is preferable that the angular interval between the third leg and the first leg is the same as the angular interval between the third leg and the second leg.

[0033] The holding device preferably includes a connecting mechanism, particularly a latch mechanism, for detachably connecting the medical image phantom to the holding device. The connecting mechanism can be a spring-fed latch mechanism, and in an advantageous embodiment, it is located in the center of the holding device. By providing a connecting mechanism, particularly a spring-fed latch mechanism, the medical image phantom can be attached to and detached from the holding device very easily.

[0034] Preferably, the coupling mechanism is operable by the user from the opposite side of the holding device relative to the medical image phantom when the medical image phantom is attached to the holding device. This allows the user to easily remove the medical image phantom from the holding device, for example, and insert it into a storage container in a single action, without having to touch the medical image phantom. Furthermore, the same applies when attaching the medical image phantom to the holding device, that is, without the user having to touch the medical image phantom.

[0035] In a preferred embodiment, the retaining device comprises a plurality, particularly three, mounting elements for precisely attaching the retaining device to a predetermined position on the detector ring. If the retaining device comprises a plurality of radially extending legs, it is preferable that one mounting element be located on each leg, and more preferably, in an advantageous embodiment, that it be located in the area of ​​the free end of each leg. In this way, the mounting elements serve to fix the retaining device on the axial end face of the detector ring. For this purpose, it is preferable that a corresponding complementary connecting element is provided on the axial end face of the detector ring, each assigned to one of the mounting elements of the retaining device. The arrangement of the mounting elements provided on the retaining device and the connecting elements provided on the axial end face of the detector ring allows the retaining device to be accurately and reproducibly positioned on the detector ring to a predetermined position.

[0036] Preferably, each mounting element has a projection or recess configured to engage with a corresponding complementary recess or projection provided on the axial end face of the detector ring. In this case, the complementary recess or projection provided on the detector ring forms a connecting element. By engaging the projection or recess with the corresponding complementary recess or projection, the retaining device can be positioned on the detector ring at a predetermined position with high repeatability.

[0037] To facilitate the installation and removal of the retaining device, each mounting element may have a magnet or be made of a ferromagnetic material so as to be magnetically attracted to a corresponding ferromagnetic element or magnet provided on the axial end face of the detector ring.

[0038] The present invention also relates to a phantom unit comprising the above-described holding device and a medical image phantom configured to be held by the holding device.

[0039] The medical imaging phantom, or at least its radioactive portion, is preferably rod-shaped overall. That is, the total length of the medical imaging phantom is preferably an integer multiple of its diameter. From the viewpoint of quality assurance and testing, it is generally advantageous for the medical imaging phantom, or its radioactive portion, to be cylindrical overall. In certain embodiments, it may be advantageous for the medical imaging phantom to be hollow cylindrical overall. In other embodiments, a configuration in which the medical imaging phantom, or at least its radioactive portion, is spherical is also conceivable. The diameter of such a spherical medical imaging phantom or radioactive portion may be approximately the same as, or roughly the same as, the inner diameter of the detector ring, or it may be an integer multiple smaller than the inner diameter of the detector ring. In the latter case, the medical imaging phantom may also be referred to as a "point source".

[0040] To facilitate the attachment of the phantom to the holding device, it is preferable that the holding device and the medical image phantom be configured to be attachable to each other while being rotated arbitrarily with respect to their respective main longitudinal directions. Therefore, if a connecting mechanism is provided, the connecting mechanism is preferably configured to be rotationally symmetric with respect to the longitudinal principal axis of the medical image phantom and / or the holding device.

[0041] In a preferred embodiment, the phantom unit is configured to ensure the quality standards of the PET scanner and / or to calibrate the PET scanner. For this purpose, the medical imaging phantom preferably comprises an elongated cylindrical radiation source formed from a radioactive material. In an advantageous embodiment, the radioactive material is a radionuclide. 22 Na or 68 It consists of Ge.

[0042] Furthermore, the present invention also relates to a method for ensuring quality standards for a medical imaging apparatus and / or calibrating a medical imaging apparatus. The method includes mounting a holding device, preferably the holding device described above, to the axial end face of the detector ring of the medical imaging apparatus, such that the holding device holds a medical imaging phantom in a specific position within the detector ring, in particular a predetermined position.

[0043] By positioning a medical image phantom at a specific location relative to the detector ring, the acquired image data can be used to verify the status and quality of the medical imaging device, and / or to calibrate the device.

[0044] Since the axial end face of the detector ring is usually more accessible than its inner surface, attaching a holding device with a medical image phantom mounted to this end face is very easy for the operator. This not only makes phantom positioning easier but also reduces the likelihood of errors.

[0045] Preferred embodiments of the present invention will be described below with reference to the drawings. These drawings are illustrative of current preferred embodiments of the present invention and do not limit the invention. [Brief explanation of the drawing]

[0046] [Figure 1] This is a schematic side view of an example of a medical imaging device as a brain PET scan device, configured to perform calibration and / or testing using a medical image phantom held by the holding device of the present invention. [Figure 2] This is a perspective view of a medical image phantom configured to be held by the holding device of the present invention. [Figure 3] Figure 2 is a perspective view from above of the holding device of the present invention with the medical image phantom attached. [Figure 4a] Figure 3 is a cross-sectional view of the holding device with the medical image phantom attached. [Figure 4b] This is a detailed, enlarged view of the rectangular area enclosed by the dashed line in Figure 4a. [Figure 4c] This is a detailed, enlarged view of the rectangular area enclosed by the dashed line in Figure 4a. [Figure 5] Figure 3 is a perspective view from below of the holding device with the medical image phantom removed. [Figure 6] This is a perspective view from the first viewpoint direction of the holding device shown in Figure 3, to which the medical image phantom is attached, as it is mounted on the detector ring of the medical imaging device. [Figure 7] This is a perspective view from a second viewpoint direction of the holding device shown in Figure 3, to which the medical image phantom is attached, as it is mounted on the detector ring of the medical imaging device. [Figure 8a] This is a partially cutaway perspective view from a third viewpoint direction of the holding device shown in Figure 3, to which the medical image phantom is attached, as it is mounted on the detector ring of the medical imaging device. [Figure 8b] This is a detailed, enlarged view of the rectangular area enclosed by the dashed line in Figure 8a. [Figure 9]Figure 2 is a perspective view of the medical image phantom as it is stored in its storage container. [Figure 10] Figure 3 is a perspective view of the mounting elements of the holding device. [Figure 11] Figure 3 is a perspective view of the latch slider in the coupling mechanism of the holding device. [Figure 12] Figure 6 is a perspective view of the connecting element of the detector ring. [Modes for carrying out the invention]

[0047] Among the elements shown in the figure, elements that have the same or similar function but belong to different embodiments are denoted by the same reference numeral in all cases.

[0048] Figure 1 shows a medical imaging device as a PET scan device 1, configured to perform calibration and / or testing using a medical image phantom held by the holding device of the present invention. The embodiment of the PET scan device 1 shown in Figure 1 is a brain scanner, i.e., a scanner specifically configured to perform PET imaging of the brain of a human patient.

[0049] In the embodiment shown in Figure 1, the PET scanning apparatus 1 includes a detector ring 11. The detector ring 11 has a plurality of sensors or sensor modules arranged within its housing. These sensors or sensor modules (not shown) each have a plurality of detection crystals arranged to face radially inward. These sensors or sensor modules perform the function of detecting and measuring PET radiation emitted within the region of the main inner opening of the annular detector ring 11.

[0050] As shown in Figures 6 and 7, the detector ring 11 has a radial outer surface 112 and a radial inner surface 111, and is generally cylindrical. The radial inner surface 111 defines the inner main opening of the detector ring 11 in the circumferential direction. The radial outer surface 112 and the radial inner surface 111 are connected to each other at each end of the cylindrical detector ring 11 by axial end surfaces 113 and 114, respectively. Because the detector ring 11, and especially its radial inner surface 111, is cylindrical, the longitudinal main axis M is defined, as shown by the dashed line in Figure 6.

[0051] The detector ring 11 is positioned between two holding arms that grip it. These two holding arms constitute part of a U-shaped section 12 that is attached to the main support structure 13. The detector ring 11 is rotatable around a rotation axis R that passes through the detector ring 11 and the two holding arms of the U-shaped section 12 in the diametrical direction (see the dashed lines in Figure 6). Furthermore, the detector ring 11, together with the U-shaped section 12, is displaceable relative to the main support structure 3 along the inclination displacement direction D. To facilitate the rotation and displacement of the detector ring 11, one or more handles 115 can be attached to the outer surface of the detector ring 11. However, the detector ring 11 can also be rotated and / or displaced by a corresponding motor. The motor can be operated by an operator, for example, via a corresponding button or touchscreen.

[0052] The direction in which the U-shaped portion 12, which has a holding arm, can be displaced is inclined with respect to the direction of gravity. That is, it is neither parallel nor perpendicular to the direction of gravity. The U-shaped portion 12 is attached to a guide rail provided on the main support structure 13, and this guide rail allows the U-shaped portion 12 to be displaced along the aforementioned inclined displacement direction D. Therefore, the guide rail also extends along this inclined direction.

[0053] The main support structure 13 is mounted on the base structure 14. Wheels 141 are attached to the base structure 14, and these wheels 141 allow the portion of the PET scan device 1 that includes the detector ring 11 and the main support structure 13 to be easily moved.

[0054] A seating support 15 is provided to seat a human patient in an inclined position during the scanning procedure. Before image acquisition, the patient is seated on the seating support 15 with the detector ring 11 in the uppermost position on the main support structure 13. The operator then displaces the detector ring 11 to the optimal position for image acquisition and rotates it as needed.

[0055] The seating support 15 comprises a seat portion 151 and an inclined backrest portion 152 for supporting the patient during the scanning procedure. A rotatable armrest 154 and a headrest 153 are attached to the backrest portion 152. During image acquisition, the patient's head is placed on the headrest 153, and the detector ring 11 is displaced and rotated so that the patient's head is positioned inside the detector ring 11. Therefore, during the image acquisition process, the headrest 153 is also positioned inside the detector ring 11.

[0056] The displacement direction D of the detector ring 11, defined by the longitudinal direction in which each guide rail extends, substantially corresponds to the longitudinal direction in which the backrest 152 and headrest 153 extend. Therefore, when the patient is seated on the seating support 15 in a predetermined posture and the scanning procedure is ready, the displacement direction D of the detector ring 11 corresponds to the longitudinal principal axis of the patient's upper body. A head strap can be used to prevent the patient from moving their head during image acquisition.

[0057] Phantom scans are performed periodically to ensure quality and / or calibrate the PET scanner. Routine periodic checks can be performed by medical technicians. These are usually performed at the start of the workday in the morning and are often mandated to ensure safety and maintain consistent performance of the PET scanner 1. The purpose of routine periodic checks is to measure deviations from the optimal performance of the PET scanner 1 and indicate when recalibration or maintenance is required. Deviations from optimal performance may relate particularly to the image quality, sensitivity, and overall imaging performance of the PET scanner 1. Therefore, routine periodic checks can be particularly useful in detecting specific problems with the PET scanner 1.

[0058] A medical imaging phantom 2, as shown in Figure 2, is used to perform routine periodic examinations. The medical imaging phantom 2, which is rod-shaped overall, has an elongated radioactive cylindrical section 22 that forms a radiation source. Therefore, the total length of the medical imaging phantom 2 is an integer multiple of its diameter. The radioactive material contained in the radioactive cylindrical section 22 is a radionuclide. 22 Na or 68 It is preferable that the material be Ge. In order to obtain reproducible scan results from measurements of the medical image phantom 2 during routine periodic inspections, it is necessary to position the medical image phantom 2, in which the radioactive material is distributed in a clearly defined and known manner within the radioactive cylindrical portion 22, at a specific location within the detector ring 11. In this example, the medical image phantom 2 forms a linear source; that is, the radioactive material is concentrated within the elongated cylinder formed by the radioactive cylindrical portion 22. When performing routine periodic inspections, the radioactive cylindrical portion 22 is positioned in the center of the detector ring 11 such that its longitudinal principal axis coincides with the longitudinal principal axis M of the detector ring 11.

[0059] To enable placement and retention within the detector ring 11, the medical image phantom 2 has a mounting portion 21 equipped with a latch structure 211 that serves to detachably attach the medical image phantom to the holding device 3. Here, the latch structure 211 is formed by a recess extending in the circumferential direction.

[0060] The holding device 3 shown in Figure 3 has three radially extending legs 31 and has an overall Y-shape. These three radially extending legs 31 are connected to each other in the central part of the holding device 3. Because the holding device 3 is Y-shaped overall, as shown in Figure 3, the angular distance between the first leg 31 and the second leg 31 is smaller than the angular distance between the third leg 31 and the first and second legs 31, respectively. All three legs 31 extend in the same plane. That is, the holding device as a whole has a flat configuration.

[0061] The medical image phantom 2 can be detachably attached to the central part of the holding device 3 via its mounting portion 21. For this purpose, the medical image phantom 2 is inserted into a connecting opening 33 provided on the lower surface of the central part of the holding device 3 via its mounting portion 21 (see Figures 4a, 4b, and 5). The dimensions of the connecting opening 33 are set to fit the mounting portion 21. A displaceable latch slider 34 is provided within the connecting opening 33. The latch slider 34 is biased in the closing direction relative to the connecting opening 33 by a compression spring 35 (see Figure 4b). The latch slider 34 includes a latch tongue 342 that is pushed into a concave latch structure 211 by the compression spring 35 after the mounting portion 21 of the medical image phantom 2 is inserted into the connecting opening 33. In this way, the medical image phantom 2 can be securely attached to the holding device 3.

[0062] To facilitate the insertion of the mounting portion 21 of the medical image phantom 2 into the connecting opening 33 and to allow the medical image phantom to be removed from the holding device 3, the latch slider 34 is equipped with an operating portion 343 that can be accessed from the upper side of the holding device 3, i.e., the side of the holding device 3 opposite to the side into which the medical image phantom 2 is inserted. By using the operating portion 343, the latch slider 34 can be displaced against the biasing force of the compression spring 35 in order to remove the medical image phantom 2 from the holding device 3 or to facilitate the insertion of the mounting portion 21 into the connecting opening 33. Because the latch slider 34 is accessible from the opposite side of the holding device 3, insertion of the medical image phantom 2 into the holding device 3 and removal from the holding device 3 become significantly easier.

[0063] Figure 11 shows a latch slider 34 as a standalone unit, comprising a latch tongue 342 and an actuation part 343. As shown in the figure, the latch slider 34 further includes a blind hole 341 on the opposite side of the latch tongue 342. This blind hole 341 serves to receive and guide the compression spring 35.

[0064] As shown in Figures 3, 4, and 4c, mounting elements 32 are provided in the free end region of each leg portion 31. The mounting elements 32 are formed by protrusions provided on the lower surface of the holding device 3 in each leg portion 31. Therefore, when the medical image phantom 2 is attached to the holding device 3 in a predetermined manner, each mounting element 32 extends in the same direction and parallel to the medical image phantom 2. Figure 10 shows one of the mounting elements 32, designed to be the same shape, as a single unit. As shown, the mounting element 32 has a substantially cylindrical shape, and a positioning tip portion 322 is formed at its tip. This positioning tip portion 322 allows the holding device 3 to be positioned on the axial end face 113 of the detector ring 11 with particularly high precision. To fix the mounting element 32 to the corresponding leg portion 31 of the holding device 3 by fixing screws 321, the main body of each mounting element 32 is provided with a screw hole 323 on the side opposite to the positioning tip portion 322 (see Figure 4c).

[0065] Each mounting element 32 is configured such that its positioning tip 322 engages with a connecting element 116 provided on the axial end face 113 of the detector ring 11. Figure 12 shows one of the connecting elements 116 individually. The connecting element 116 has a recess 117 for receiving the positioning tip 322 of the corresponding mounting element 32 (see Figure 8b). The complementary shapes of the recess 117 and the positioning tip 322 ensure that the position of the holding device 3 on the detector ring 11 is precisely defined.

[0066] To facilitate installation and to hold the holding device 3 on the detector ring 11, each mounting element 32 forms a magnet, and each corresponding connecting element 116 is made of a ferromagnetic material (this relationship may be reversed). As a result, the mounting elements 32 and the corresponding connecting elements 116 attract each other by magnetic force. The combination of the shapes of the mounting elements 32 and connecting elements 116 and their magnetic attraction allows the holding device 3 with the medical image phantom 2 attached to be positioned on the axial end face 113 of the detector ring 11 with great ease, high precision, and accuracy.

[0067] As shown in Figures 6 to 8a, when the holding device 3 is attached to the detector ring 11 in a predetermined manner, it does not protrude into the main opening of the detector ring 11, but is positioned flat on the axial end face 113 of the detector ring, i.e., outside the main opening. In this mounting state, the longitudinal principal axis of the radioactive cylindrical portion 22 of the medical image phantom 2 coincides with the longitudinal principal axis M of the detector ring 11. Along the axial direction, the radioactive cylindrical portion 22 is positioned in the center of the detector ring 11.

[0068] Figure 9 shows the medical imaging phantom 2 after being removed from the holding device 3 and inserted into the storage container 4 for storage. The storage container 4 forms a radiation shield against the radioactive material contained within the medical imaging phantom 2. Therefore, it is preferable that the storage container 4 be made of lead. In technical terms, this storage container 4 is sometimes called a "leadpig" (lead shielding container).

[0069] In routine periodic inspections, the medical image phantom 2 is connected to the holding device 3, and after attaching the holding device 3 to the axial end face 113 of the detector ring 11, data is acquired based on the radiation emission from the radioactive cylindrical portion 22 located within the detector ring 11. A standardized sequence is executed during data acquisition. The acquired data is post-processed, analyzed, displayed as necessary, and compared with reference data. Based on certain evaluation criteria, it is automatically determined by the operator or, for example, by software, whether the PET scan device 1 meets the quality standards. If the required quality standards are not met, the next step may be to perform a calibration or recalibration procedure. This procedure can also be performed based on the data acquired from the medical image phantom 2. Data acquisition and post-processing in routine periodic inspections and / or calibration procedures may target single events and / or coincidence events.

[0070] The present invention is, of course, not limited to the embodiments and examples described above, and various modifications are possible. For example, the holding device does not necessarily have to be Y-shaped with multiple legs. For example, a configuration in which the holding device as a whole is a flat disc shape is also conceivable. In other embodiments, the holding device may comprise a first part and a separate second part, wherein the first part is configured to be attached to the axial end face 113 of the detector ring 11, and the second part is configured to be attached to the axial end face 114 of the detector ring 11. This allows the medical image phantom 2 to be held more firmly and stably on the detector ring 11. Furthermore, the mounting elements of the holding device and / or the connecting elements of the detector ring may have different configurations. Also, different designs are possible for the connecting mechanism between the holding device and the medical image phantom. For example, a configuration in which the holding device is fixedly, i.e., non-removable, attached to the medical image phantom is also conceivable. Various other modifications are also possible. [Explanation of symbols]

[0071] 1…PET scanner 11… Pixel ring 111...Inner self 112...External surface 113...Axial end face 114...Axial end face 115... Handle 116…Connecting element 117…recess 12...U-shaped part 13...Main support structure 14...Base structure 141...Wheel 15…Seating support 151...Seat part 152... Backrest 153... Headrest 154... Armrest 2… Medical imaging phantom 21…Mounting part 211...Latch structure 22...Radioactive cylindrical section 3...Holding device 31...legs 32…Mounting elements 321... Fixing screw 322...Positioning tip 323... screw hole 33...Connection opening 34...Latch slider 341...Bullet hole 342...Latch tongue 343... Operating part 35... Compression spring 4…Storage containers R... Rotation axis D4 Displacement direction M... Longitudinal axis

Claims

1. A medical imaging device holding device (3) for holding a medical imaging device, particularly a medical imaging device in the form of a positron emission tomography (PET) scanning device (1), in a specific position within the detector ring (11), The holding device (3) is characterized in that it is configured to be attached to the axial end faces (113, 114) of the detector ring (111).

2. The holding device (3) according to claim 1, characterized in that the holding device (3) is configured to hold the medical image phantom (2) such that the medical image phantom (2) penetrates the center of the detector ring and extends in particular along the longitudinal principal axis (M) of the detector ring.

3. The holding device (3) according to claim 1 or 2, comprising a plurality of radially extending legs, particularly three legs (31), each configured to be attached to the axial end faces (113, 114) of the detector ring (111).

4. The holding device (3) according to any one of claims 1 to 3, characterized in that the holding device (3) has a Y-shaped form overall.

5. The holding device (3) according to any one of claims 1 to 4, characterized in that it is equipped with a connecting mechanism for detachably connecting the medical image phantom (2) to the holding device (3), particularly in the form of a latch mechanism (34, 211).

6. The holding device (3) according to claim 5, characterized in that the connecting mechanism (34, 211) can be operated by a user from the opposite side of the holding device (3) relative to the medical image phantom (2) when the medical image phantom (2) is attached to the holding device (3).

7. The retaining device (3) according to any one of claims 1 to 6, characterized in that it comprises a plurality, in particular three, mounting elements (32) for precisely attaching the retaining device (3) to a predetermined position on the detector ring (11).

8. The retaining device (3) according to claim 7, characterized in that each of the mounting elements (32) has a projection or recess configured to engage with a corresponding complementary recess (117) or projection provided on the axial end face (113, 114) of the detector ring (11).

9. The holding device (3) according to claim 7 or 8, characterized in that each of the mounting elements (32) is formed to be attracted by magnetic force to a corresponding ferromagnetic element or magnet provided on the axial end face (113, 114) of the detector ring (11), or is made of a ferromagnetic material.

10. A holding device (3) according to any one of claims 1 to 9, A medical image phantom (2) is configured to be held by the holding device (3), A phantom unit characterized by being equipped with the following features.

11. The phantom unit according to claim 10, characterized in that the medical image phantom (2) has a rod-shaped form overall.

12. The phantom unit is configured to ensure the quality standards of the PET scan device (1) and / or to calibrate the PET scan device (1), The aforementioned medical image phantom (2) is equipped with an elongated cylindrical radiation source made of radioactive material for this purpose, The radioactive material is preferably a radionuclide. ２２ Na or ６８ The phantom unit according to claim 11, characterized in that it is composed of Ge.

13. A method for ensuring the quality standards of a medical imaging device (1) and / or for calibrating a medical imaging device (1), A method comprising the step of attaching a holding device (3), preferably a holding device (3) as described in any one of claims 1 to 9, to the axial end faces (113, 114) of the detector ring (11) of the medical imaging device (1) such that the medical image phantom (2) is held in a specific position within the detector ring (11) by the holding device (3).

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