NL2035862B1 - A gamma radiation imaging system and method - Google Patents

Abstract

-15- A B S T R A C T A gamma radiation imaging system, for example for scintimammography, comprises immobilization plates configured to clamp a body part to be imaged, e.g. a breast, between them. A first plate is provided with a grid of tool apertures. A first gamma camera comprises a first collimator assembly which has a collimator part provided with one or more sets of collimator openings and a non-collimating support part adjoining the collimator part. The noncollimating support part may comprise support ribs defining openings. The first collimator assembly is slidable between a position wherein the collimator part is in operative position for 10 imaging and a position wherein the non-collimating support part is in the operative position for use in passing a tool through an aligned opening of the support part and a tool aperture.

Description

P36454NL00

A GAMMA RADIATION IMAGING SYSTEM AND METHOD

The present invention relates to a gamma radiation imaging system, for example for scintimammography or for imaging another human body part, e.g. an extremity like an arm or a leg.

Known systems for scintimammography are described, for example, in WO2010008538,

WO02010/014001, WO2010120636, US2013/0158389, and US105159456.

The present invention aims to provide an improved system, in particular an improved scintimammography system.

The present invention aims to provide a system which has an increased sensitivity and/or allows for a reduction of the dose of tracer material that is to be applied, commonly injected, to the person in view of the imaging. The present invention also or alternatively aims to reduce the time required for the imaging, e.g. enhancing comfort for the person, and/or increased accuracy of the localization of the region of interest, e.g. a tumorous lesion.

The present invention provides a gamma radiation imaging system, for example for scintimammography, according to claim 1.

The system comprises: - a frame supporting a first immobilization plate and a second immobilization plate, e.g. parallel to the first immobilization plate, the plates defining an imaging space between them and configured to clamp a body part to be imaged, e.g. a breast, between the plates, wherein at least the first immobilization plate is provided with a grid of tool apertures each configured to allow for passage of a tool through the first immobilization plate, - a first gamma camera configured and arranged to detect gamma radiation emitted from a volume in the imaging space passing through the first immobilization plate, wherein the first gamma camera comprises: - a first collimator assembly, which extends in a plane parallel to the first immobilization plate,

- a first gamma sensitive detector arranged to receive gamma radiation passing through the first collimator, wherein the first collimator assembly slidably rests against a face of the first immobilization plate that is facing away from the imaging space, and which first collimator assembly is movable in said plane relative to the respective immobilization plate in a displacement direction, wherein the first collimator assembly has a collimator part provided with one or more sets of collimator openings, e.g. holes or pinholes, through which gamma radiation passes from the imaging space to the detector, wherein the first collimator assembly has a non-collimating support part adjoining the collimator part, which non-collimating support part is configured to pass a tool there through into a tool aperture, wherein the first collimator assembly is slidable selectively between a position wherein the collimator part is in operative position for imaging and a position wherein the non-collimating support part is in the operative position for use in passing a tool through the support part and atool aperture.

In a practical embodiment, the non-collimating support part comprises multiple openings which are open at the face of the first immobilization plate and opposite thereof, and which openings of the non-collimating support part are greater than each of the tool apertures in the first immobilization plate, so that in the operative position a tool can be passed through an aligned opening of the support part and a tool aperture. In a practical embodiment, the non- collimating support part comprises support ribs defining the multiple openings. Due to the openings, e.g. defined between the ribs, the tool has access to a selected aperture in the plate, e.g. to penetrate a biopsy tool into a breast of a female person.

In an embodiment, the non-collimating support part is made of a pierceable material, e.g. of a plastic foam material, e.g. a rigid plastic foam material, that — in use — is to be pierced by the tool that is to be passed through the support part and a tool aperture.

Due to the provision of the non-collimating support part adjoining the collimator part it is possible to keep the body part immobilized when it is desired to perform an activity requiring a tool, e.g. a biopsy tool or a marking tool, after the imaging has been done. The collimator part is then slid away from the operative position and the adjoining non-collimating support part slides into the operative position.

Also, due to the provision of the non-collimating support part adjoining the collimator part, it is possible to embody the immobilization plate rather thin. In practical embodiments, the immobilization plate has a thickness of less than 5 millimeters, more preferably between 1 and 3 millimeters. A thin immobilization plate would, by itself, bend under the loading during clamping of the body part, e.g. when the collimating part would be removed in order to perform an activity involving a tool that is to be passed through a tool aperture in the immobilization plate. Due to the inventive collimator assembly, this bending is countered by the non-collimating support part as the structure thereof provides the desired structural support for the rather thin plate.

The possibility to have a rather thin immobilization plate is, in turn, beneficial for the quality of the imaging process, e.g. as the collimator part can be closer to the body part that is to be imaged compared to an immobilization plate that is thicker in order to absorb the bending load thereon without the benefit of the inventive design. Improved imaging may enhance, for example, detection and/or localization of a region of interest, e.g. a tumorous lesion in the body part.

A further benefit of the inventive design may be the reduction of the time required for the imaging combined with the follow-up action involving the tool, e.g. enhancing comfort for the person whose body part, e.g. breast, is to be examined.

For example, the rib structure forms a rectangular grate of ribs or a honeycomb arrangement of ribs.

In a practical embodiment, the collimator part and the non-collimating support part of the assembly are connected to one another, e.g. permanently or, as preferred, by a releasable connection, e.g. screws, bolts, magnets, or other releasable connectors. A releasable connection, e.g., allows to provide different combinations of collimator part(s) and non- collimating support part(s). For example, one could combine a non-collimating support part with a selected one of different collimator parts, e.g. collimator parts having a different configurations to provide different imaging properties.

In a practical embodiment, the collimator part and the non-collimating support part are not connected to one another, yet arranged in an adjoining configuration. For example, the non-

collimating support part is pushed against the collimator part when the collimator part is to be slid away from the operative position. In an embodiment, the non-collimating support part is configured to be manually moved into the adjoining arrangement, e.g. to manually slide the collimator part away from the operative position as the non-collimating support part is manually slid into the operative position.

In an embodiment, the non-collimating support part is made of plastic, e.g. fibre reinforced plastic, e.g. with carbon fibre reinforcement. For example, the support part is injection molded or 3D printed, e.g. to form the rib structure.

In an embodiment, the system comprises a set of different non-collimating support parts, e.g. having different designs of the openings therein and/or different features configured to interact with one or more specific tools.

In an embodiment, the system further comprises an tool orientation device configured to be releasably mated with the non-collimating support part and to interact with a tool that is to be passed through a tool aperture so as to provide for correct orientation of the tool. The orientation provided by the tool orientation device may comprise one or more of the position of the tool in the plane of the immobilization plate, the angle of the tool relative to the immobilization plate (e.g. the tool orientation device being configured to keep the tool perpendicular to the immobilization plate or at a specific angle). For example, the tool orientation device is configured to be mated with one or more ribs of the non-collimating support part.

For example, the grid of tool apertures is a uniform, e.g. rectangular, grid with equidistant spaced tool apertures.

In practical embodiments, the tool apertures are circular, e.g. having a diameter between 2 mm and 8 mm, e.g. of about 5 mm. In practical embodiments, the tool apertures are closely spaced from one another, e.g. less spacing between apertures than their diameter. The tool apertures may be non-circular.

Preferably, the system comprises a collimator motion device configured to controllably move the collimator assembly in the displacement direction, preferably only in the one displacement direction.

Preferably, the detector is a position sensitive detector. Such a detector gives information about in which part of the detector the gamma photon has interacted.

The system is, in a preferred embodiment, configured for scintimammography, e.g. with the person standing or sitting when a breast thereof is imaged using the system.

In a practical embodiment, at least one of the immobilization plates is movable in a direction substantially towards the other plate, e.g. allowing for a breast to be held immobile under compression. In general compression will cause the human body part to remain in place with respect to the plates and the cameras, so enhancing the quality of the image. Also compression, at least in case of a breast, makes the part to be imaged thinner, and the obtained images more unambiguous.

In a practical embodiment, the immobilization plates are parallel during imaging. In an embodiment, at least one of the immobilization plates and the associated collimator assembly and/or entire gamma camera is tiltable, e.g. allowing for the immobilization plates to be arranged at will parallel or non-parallel during imaging.

In a practical embodiment, during imaging, e.g. during a step of the imaging process as discussed herein, the gamma camera including the respective collimator assembly is stationary relative to the imaging space.

In a practical embodiment, at least one of the immobilization plates is transparent for visible light allowing to see through the plate by the human eye, e.g. the plate having the tool apertures.

In a practical embodiment, the collimators assembly or assemblies is/are formed by one or more plate shaped components having parallel main faces.

In an embodiment, the system further comprises a biopsy tool, that is configured to pass through an aligned opening of the support part and a tool aperture and is adapted to perform a biopsy of the human body part.

In an embodiment, the system further comprises a comprising a marker tool, that is configured to pass through an aligned opening of the support part and a tool aperture and is adapted to mark the human body part. Marking may be of relevance, for example, when surgery is to be performed. For example, a mark is made where a peak is registered in the

-B- radiation emitted from the body part. The mark may facilitate surgical removal of a tumorous lesion. In embodiments, the mark is a visual mark, e.g. made with ink or the like. In embodiments, the mark is gamma-radioactive and is penetrated into the human body part, allowing the marker to be seen and used in a subsequent scan/image.

In an embodiment, the system further comprises a second gamma camera configured and arranged to detect gamma radiation emitted from a volume in the imaging space passing through the second immobilization plate, wherein the second gamma camera comprises: - a second collimator assembly, which extends in a plane parallel to the second immobilization plate, - a second gamma sensitive detector arranged to receive gamma radiation passing through the second collimator assembly.

In an embodiment, the second collimator assembly is movable in said plane in a displacement direction relative to the second immobilization plate, preferably by collimator motion device configured to controllably move the collimator assembly in the displacement direction,

In an embodiment, the first and/or second collimator assembly comprises a collimator part provided with parallel holes having an axis which extends perpendicular to the immobilization plate.

In an embodiment, the first and/or second collimator assembly comprises a collimator part composed of a first section and a second section adjoining the first section, wherein the first section is provided with a set of parallel first holes having a first axis at a first angle with the immobilization plate, wherein the second section is provided with a set of parallel second holes having a second axis at a second angle with the immobilization plate, wherein the first and second holes are configured such that the first and second axes are located in one or more planes perpendicular to the immobilization plate and extending parallel to the displacement direction, and such that first and second axes intersect or cross in the imaging space.

In an embodiment, the first and/or second collimator assembly comprises both a collimator part with parallel holes perpendicular to the immobilization plate, and a collimator part having another configuration of holes, e.g. holes at an angle, e.g. as discussed in the paragraph above, as well as the non-collimating support part for the first collimator assembly.

The present invention also relates to a method of gamma imaging of a human body part, e.g. of a breast, and performing an activity involving a tool, wherein use is made of the system as described herein.

The invention will now be explained with reference to the drawings. In the drawings: - fig. 1 shows schematically an embodiment of a system according to the invention during performance of a biopsy as a follow-up after an imaging process using the system, - fig. 2 shows the system of figure 1 from another angle, - fig. 3 shows the system of figure 1 from yet another angle, - fig. 4 shows the system of figure 1 from yet another angle.

With reference to the figures an example of a gamma radiation imaging for scintimammography and follow up by biopsy according to the invention will be discussed.

The system comprises a frame 1, only shown highly schematically, supporting a first immobilization plate 10 and a second immobilization plate 110 which here extends parallel to the first immobilization plate 10. The plates 10, 110 define an imaging space 200 between them for one breast 250 (shown schematic) of a female human person, e.g. standing or sitting.

The system is configured to clamp the breast to be imaged between the plates 10, 110.

In a practical embodiment, the plates 10, 110 are made of plastic material, e.g. one or both plates of a visually transparent plastic material.

The first immobilization plate 10 is provided with a 2D-grid of tool apertures 15, which are each configured to allow for passage of a tool 300 through the first immobilization plate 10. In practical embodiments, the plate 10 has a multitude of apertures 15, closely spaced from one another. In practical embodiments, e.g. in view of the tool(s) that is to be passed through an aperture, the diameter of each aperture 15 may be several millimeters, e.g. between 3 and 8 millimeters, e.g. about 5 — 6 millimeters.

The system further comprises a first gamma camera 50 which is configured and arranged to detect gamma radiation emitted from the breast 250 in the imaging space passing through the first immobilization plate 10.

The system further comprises a second gamma camera 150 which is configured and arranged to detect gamma radiation emitted from the breast 250 in the imaging space passing through the second immobilization plate 110.

The first gamma camera 50 comprises: - a first collimator assembly 60, which extends in a plane parallel to the first immobilization plate 10, - a first gamma sensitive detector 80 arranged to receive gamma radiation passing through the first collimator assembly 60.

The second gamma camera 150 comprises: - a second collimator assembly 160, which extends in a plane parallel to the second immobilization plate 110, - a second gamma sensitive detector 180 arranged to receive gamma radiation passing through the second collimator assembly 160.

It is noted that in the figures the detectors 80, 180 are shown to be quite far away from the associated collimator assembly. This is done for clarity of the figures, in practical embodiments the detectors 80, 180 are in close proximity to the associated collimator assembly.

The first and the second collimator assemblies 60, 160 are each movable in the plane of the corresponding plate 10, 110 in a displacement direction Y relative to the respective immobilization plate.

The collimator assembly 60 is guided by guide rails 5, 6 of the frame of the system.

Each collimator assembly 60, 160 is linearly driven in Y-direction by a corresponding collimator motion device 95, 195 which configured to controllably move the collimator assembly in the displacement direction Y.

The X-direction extends in the plane of the plates 10, 110, perpendicular to the Y-direction.

As shown, the first collimator assembly 60 slidably rests against a face of the first immobilization plate 10 that is facing away from the imaging space 200.

The first collimator assembly has a collimator part 65 which is provided with one or more sets of collimator openings, e.g. holes 66 or pinholes, through which gamma radiation passes from the imaging space to the detector 80.

The first collimator assembly has a non-collimating support part 75 adjoining the collimator part 65.

The non-collimating support part 75, e.g. made of plastic, comprises support ribs 76, here a grate of ribs 76, here a rectangular grate of ribs 76. The ribs 76 define openings 77 which are open at the face of the first immobilization plate 10 as well as opposite thereof.

In embodiments, the ribs 76 have a height perpendicular to the plate 10 and a width that is less than the height.

The cross-section of the ribs 75 may be uniform over the length of the ribs, but other configurations are also envisaged. The ribs 76 may be rectilinear, as shown, but also could be curved, undulating, etc.

The openings 77 of the non-collimating support part 75 are greater than each of the tool apertures 15 in the first immobilization plate 10. In practical embodiments, one opening 77 is greater in size than a subgroup of multiple apertures in the plate 10. For example, one opening 77 is 40 millimeters by 40 millimeters, seen from above.

The first collimator assembly 60 is slidable selectively between a position wherein the collimator part 65 is in operative position for imaging of the breast with the first gamma camera 50 and a position, shown in figures 1,2, and 3, wherein the non-collimating support part 75 is in the operative position thereof for use in passing the tool 300 through an aligned opening 77 of the support part 75 and a tool aperture 15 in the plate 10.

In use, the breast 250 is clamped between the plates 10, 110, e.g. by moving the plate 10 along with the assembly 60, the detector 80, and rest of camera 50 towards the other plate 110.

Due to the provision of the non-collimating support part 75 adjoining the collimator part, it is possible to embody the immobilization plate 10 rather thin.

In practical embodiments, the immobilization plate 10, e.g. the plastic plate 10, has a thickness of less than 5 millimeters, more preferably between 1 and 3 millimeters, e.g. 2-3 millimeters.

Athinimmobilization plate 10 would, by itself, bend under the loading during clamping of the body part, here breast 250, e.g. when the collimating part would be removed in order to perform an activity involving the tool 300 that is to be passed through a selected tool aperture 15 in the immobilization plate 10. Due to the inventive structure of the collimator assembly, this bending is countered by the non-collimating support part 75 as the rib structure thereof provides the desired structural support for the rather thin plate 10. This support is provided throughout the step of sliding the assembly such that the collimator part is slid away from the operative position and the support part 75 in slid into the operative position.

Due to the openings defined between the ribs of part 75, the tool 300 has access to a selected aperture 15 in the plate 10, e.g. to penetrate a biopsy tool into a breast 250 of a female person.

In practical embodiments, one or more friction reducing features may be present in the system to reduce friction between the plate 10 and the assembly 60 during sliding. For example, a Teflon coating is provided, pressurized air or another lubricant is used between the plate 10 and the assembly 60, etc.

The second collimator assembly 160 has a first collimator part 161 composed of a first section 165 and a second section 170 adjoining the first section 165 in the displacement direction Y.

In this example, the first section 185 is provided with a set of parallel first holes having a first axis at a first angle with the second immobilization plate 110. The second section 170 is provided with a set of parallel second holes having a second axis at a second angle with the second immobilization plate 110. The first and second holes are configured such that the first and second axes are located in one or more planes perpendicular to the second immobilization plate 110 and extending parallel to the displacement direction Y, and such that first and second axes intersect or cross in the imaging space 200 seen in X-direction.

The second collimator assembly further comprises, as an example, a second collimator part 175, wherein the second collimator part is provided with parallel third holes 176 having a third axis which extends perpendicular to the second immobilization plate 110.

The collimator assemblies 80, 160 here each are embodied as one component that is slidable in Y-direction along a side of the respective immobilization plate 10, 110 that faces away from the imaging space 200.

When it is determined that a biopsy of the region of interest is desired, the breast 250 remains immobilized by the plates 10, 110.

Part of the first gamma camera 50, at least including the detector 80 in practice also including a housing between the detector 80 and the collimator assembly 60, is repositioned away from the operative position thereof to provide space for the tool 300 and access to the apertures 15. The tool 300 is then passed through an opening in the part 75 and an aperture so as to penetrate into the breast 250, make a mark on the breast, etc.

Repositioning of the first gamma camera 50, at least the detector 80, in order to provide 15 access for the tool 300 is done here by camera drive 85.

In an embodiment, not shown, the system further comprises a tool orientation device configured to be releasably mated with the non-collimating support part and to interact with the tool 300 that is to be passed through a tool aperture so as to provide for correct orientation of the tool. The orientation provided by the tool orientation device may comprise one or more of the position of the tool 300 in the plane of the immobilization plate, the angle of the tool 300 relative to the immobilization plate (e.g. the tool orientation device being configured to keep the tool perpendicular to the immobilization plate or at a specific angle).

For example, the tool orientation device is configured to be mated with one or more ribs of the non-collimating support part 75. For example, the tool orientation device has a mating portion that fits into one or more openings of the part 75 to mate the device with the part 75.

During taking of a biopsy with tool 300, the second gamma camera 150 can, if desired, be operational, e.g. to monitor penetration of the tool into the part 250. For example, part 161 of the assembly 160 is used during taking of a biopsy, e.g. the join between sections 165 and 170 being aligned with the location of the biopsy tool 300 to optimize monitoring of penetration depth, e.g. the biopsy tool, e.g. the tip thereof, being provided with a tracer emitting gamma radiation.

Claims (11)

CONCLUSIONS 1. Gamma-ray imaging system, e.g. for scintimammography, comprising: - a frame (1) supporting a first immobilization plate (10) and a second immobilization plate (110), e.g. parallel to the first immobilization plate, the immobilization plate defining an imaging space between them and adapted to clamp a body part (250) being imaged, e.g. a breast, between the plates, at least the first immobilization plate (10) being provided with a grid of tool openings (15) each adapted to allow the passage of a tool (300) through the first immobilization plate, - a first gamma camera (50) adapted and arranged to detect gamma radiation emitted from a volume in the imaging space passing through the first immobilization plate, the first gamma camera comprising: - a first collimator assembly (60) extending in a plane parallel to the first immobilization plate, - a first gamma-sensitive detector (80) arranged to detect gamma radiation which passes through the first collimator, the first collimator assembly (60) slidably resting against a face of the first immobilization plate (10) facing away from the imaging space, and the first collimator assembly being movable in said face relative to the respective immobilization plate in a direction of displacement (Y), preferably by the collimator movement device arranged to controllably move the collimator assembly, the first collimator assembly having a collimator portion (65) provided with one or more sets of apertures (66) through which gamma radiation passes from the imaging space to the detector (80), wherein the first collimator assembly has a non-collimating support member (75) adjacent to the collimator member (65), the non-collimating support member being configured to allow a tool (300) to be passed therethrough into a tool opening (15), the first collimator assembly (60) being selectively slidable between a position where the collimator member (65) is in an operative position for imaging and a position where the non-collimating support member (75) is in an operative position for use in passing a tool (300) through the support member (75) and a tool opening (15). The system of claim 1, wherein the non-collimating support member (75) comprises a plurality of openings (77) open at the plane of the first immobilization plate (10) and opposite thereto, and wherein the openings (77) of the non-collimating support member (75) are larger than each of the tool openings (15) in the first immobilization plate such that in the operative position a tool (300) can be passed through an aligned opening (77) of the support member (75) and a tool opening (15). The system of claim 2, wherein the non-collimating support member (75) comprises support ribs (76) defining a plurality of openings (77). 4. A system according to any one or more of the preceding claims 1-3, wherein the non-collimating support member is made of a pierceable material, for example a plastic foam material, for example a solid plastic foam material, which — in use — is pierced by the tool passing through the support member (75) and a tool opening (15). 5. The system of any one of claims 1 to 4, wherein the system further comprises a biopsy tool (300) adapted to pass through the support member (75) and a tool opening (15) and adapted to perform a biopsy of a human body part. 6. A system according to any one of the preceding claims 1-5, wherein the system further comprises a marking device adapted to pass through the support member and a tool opening and adapted to mark the human body part. The system of any one of claims 1 to 6, wherein the system further comprises a second gamma camera (150) configured and arranged to detect gamma radiation emitted from a volume in the imaging space and passing through the second immobilization plate, the second gamma camera comprising: - a second collimator assembly (160) extending in a plane parallel to the second immobilization plate (110), - a second gamma-sensitive detector (180) arranged to detect gamma radiation passing through the second collimator assembly. The system of claim 7, wherein the second collimator assembly (160) is movable in said plane in a direction of displacement relative to the second immobilization plate, preferably by a collimator movement device arranged to controllably move the collimator assembly in the direction of displacement. 9. System according to one or more of the preceding claims 1-8, wherein the first and/or second collimator assembly (60,160) comprises a collimator portion (175) provided with parallel holes having an axis perpendicular to the immobilization plate. The system of any one of claims 1 to 9, wherein the first and/or second collimator assembly comprises a collimator portion (161) composed of a first portion and a second portion adjacent to the first portion, the first portion having an array of parallel first holes (165) having a first axis at a first angle to the immobilization plate (110), the second portion having an array of parallel second holes (170) having a second axis at a second angle to the immobilization plate (110), the first and second holes being arranged such that the first and second axes are in one or more planes perpendicular to the immobilization plate and extend parallel to the direction of movement, and such that the first and second axes intersect or cross each other in the imaging space. 11. Method of gamma imaging of a human body part, for example a breast (250), using the system according to one or more of claims 1 to 10.