Quality assurance system for particle radiotherapy

Abstract

1. A quality assurance system (2) for radiation therapy used in a treatment apparatus (100) including a treatment couch (101) and a particle radiation device (103) having a radiation emitter head (104) for particle beam radiation, the quality assurance system including: a detector device (3) including at least one detection module (8) configured to measure gamma radiation emitted by a target object receiving the particle radiation beam; and a support mechanism (7) to which the at least one detection module (8) is mounted, the support mechanism (7) including a base (12) configured to connect to the treatment couch (101) of the treatment apparatus (100) and at least one detection module support structure (18) pivotally connected to the base (12) via a pivot connection (16).

Description

[Technical Field]

[0001] The present invention relates to a system for quality assurance of particle radiotherapy, particularly for measuring secondary radiation induced by particle-target interactions, which may include, but are not limited to, patients, animals, phantoms of various materials, cadavers, mixed or heterogeneous tissues, organs or other biological samples. [Background technology]

[0002] During radiation therapy, the patient is typically irradiated with the particle beam from several different angles due to relative motion (translation and / or rotation) between the patient treatment couch (on which the patient rests) and a rotating beam guide structure (gantry). The precision and accuracy with which the intended dose distribution can be delivered to the irradiation target within the patient depends primarily on two sources of error: (i) External and mechanical factors of the target Alignment: How well different devices are aligned relative to a common virtual reference point (the "isocenter"). Examples of such devices are the treatment couch on which the patient rests, the gantry, the optical guidance systems used for device calibration and quality assurance, or the imaging devices used to verify the patient's positioning in direct relation to the delivery. · Beam delivery: Errors in beam position, energy, direction, current, dwell time per spot, or shape, for example, can cause over- or under-dose. Target setup error: Differences in the positioning of the target volume relative to its intended location or the location assumed in the treatment plan. This can be due to factors such as target translation or rotation, or target deformation. (ii) Target modeling factors Unlike photon radiotherapy, which uses X-rays or gamma rays, particle radiotherapy (especially when using protons or ions) is highly sensitive to range uncertainties. Unlike an exponentially decreasing depth-dose curve, the depth-dose profile of charged particles decelerating in matter ends with a sharp Bragg peak, i.e., a very high dose is delivered just before the particle stops. This has the advantage that the composite dose from particles delivered from one or more angles or different energies can be tailored to produce the intended dose in the target region while minimizing dose to, for example, healthy tissue. At the same time, correctly modeling the particle deceleration process within the target is crucial for correctly predicting where the particle will stop. Modeling errors can be caused, for example, by artifacts in X-ray or CT images, changes in the patient's anatomy during the course of treatment, variations in how the target is set up and immobilized on the treatment table, or errors in the treatment planning system (TPS) in predicting stopping power across various parts of the target.

[0003] Quality assurance (QA) devices are used to assess and quantify any clinically relevant effects of various error sources and, where reasonably possible, eliminate or offset through calibration. QA procedures should be performed regularly to provide confidence that patients receive the intended dose distribution. Examples are provided below.

[0004] Beam QA Measurement One category of QA measurements involves verifying that relevant beam characteristics are within acceptable tolerances. Such characteristics can be the size, shape (profile), and position of individual beams or spots, typically measured near the isocenter in a plane orthogonal to the beam axis. Other measurements may be aimed at calibrating or verifying the calibration of beam intensity or dose monitors, which are used to determine when the assigned number of particles has been delivered to the smallest subset ("spot") of the treatment plan. Such measurements are critical to ensuring that an acceptable dose distribution is delivered and typically require submillimeter and subpercent precision and accuracy for spatial and charge measurements, respectively.

[0005] QA devices based on destructive ionization measurements. U.S. Patent Application Publication No. 2010 / 0108901 discloses a multi-layer ionization chamber designed to measure one-dimensional depth dose profiles of proton beams by blocking, absorbing, and stopping them. This device can be placed on a treatment table, facing the beam, and can measure the depth dose curve ("Bragg curve") of a single proton beam spot or a composite depth dose curve from multiple beam spots that may form an extended Bragg peak. This type of prior art has the disadvantage that the measurements are destructive; it is not possible to measure the dose distribution within the target noninvasively. It is possible to indirectly measure the total beam energy loss in the target by irradiating a proton beam through the target and measuring the shift in the Bragg curve compared to irradiating a proton beam of the same initial energy directly into the multi-layer ionization chamber. However, this method does not allow for the internal variation of the beam stopping power along the beam axis within the target; only the integral stopping power across the target can be measured by the device. Depth dosimetry devices can only be used to generate tomographic stopping power images of a target by repeated measurements of the integrated stopping power from multiple directions ("proton tomography"). This has the disadvantage that it requires an extensive series of measurements combined with repeated repositioning of the target or device configuration, since the device can only block the beam from a single direction (perpendicular to the ionization chamber).

[0006] The device disclosed in U.S. Patent Application Publication No. 2010 / 0108901 cannot block a proton beam delivered from many different directions, as required in a typical clinically relevant treatment plan. Furthermore, the device also has a limited aperture, a few centimeters in diameter, within which the beam can be blocked. This is smaller than the available cross-section of the scanned beam field, which can range up to 20 x 20 cm or larger, depending on the beam delivery system (BDS).

[0007] Another type of QA device is disclosed in EP 1907062 B1, which is based on multiple smaller ionization chambers arranged in a plane. Such and similar devices can be used to verify that the transverse coordinates of a scanned beam are as intended, for example, in a plane containing the isocenter. However, this type of device also cannot directly measure where or how the beam is decelerating within the target.

[0008] Proton computed tomography An example of a device specifically intended for clinical proton computed tomography of patients is disclosed in U.S. Patent Application Publication No. 2011220794A1. Disadvantages of this device include: the target must be illuminated from many different directions by rotating the detector elements of the device in unison with the rotation of the gantry, which requires that the device be mechanically mounted on the gantry to ensure that it rotates in unison with the gantry, or that the device must be integrated with a gantry rotation control system to ensure that the motion of the device and the gantry are coordinated; The available proton beam energy must be high enough to allow the beam to traverse the entire target and impinge on the detector element downstream of the target, as multiple Coulomb scattering at the target and air gap can significantly increase the transverse spot size of the proton beam as it reaches the detector downstream of the target, effectively limiting the spatial resolution of the tomographic stopping power image. -It is not possible to determine the stopping power in the inner regions of a target without obtaining a complete tomographic data set from the periphery of the target.

[0009] Immutability Checks A "consistency check" is a measurement performed to verify that a reference treatment plan is consistently delivered, for example, after a hardware or software upgrade or machine maintenance, or as part of regular routine management. Typically, this is done by delivering the treatment plan under well-defined conditions and ensuring that recordings from various QA devices match previous measurements. A drawback of existing QA devices is that such measurements can only be performed for a limited set of beam parameters. In particular, the referenced prior art QA devices do not allow for delivery from all directions and are limited to "front-facing" delivery. For example, verifying that the position and extent of a scanned beam are as intended across a wide or continuous range of gantry angles is difficult and impractical. Such QA measurements are particularly relevant for arc therapy, which consists of continuous or quasi-continuous delivery of the beam as the gantry rotates and / or the couch moves.

[0010] QA by patient Patient-specific QA may involve delivering the patient-specific treatment plan into the target. After delivery, log files from devices such as beam monitors in the radiation emitter head, which may contain information related to the actual number of delivered particles per spot or the measured position of the scanned beam, can be used to recalculate what the delivered dose distribution looked like in the patient based on the same patient-specific model used to design the treatment plan. Patient-specific QA may also involve delivering the patient-specific treatment plan into a water tank, e.g., with a point or 2D ionization chamber. The measured dose is compared to the recalculated dose distribution in water. Such QA procedures only address uncertainties in beam delivery and do not address potential errors in the patient / target anatomical model that could result in, for example, overshoot or undershoot.

[0011] More generally, it is important to ensure that the delivered radiation is spatially and dosimetry accurate and accurately covers the intended treatment area, taking into account errors and uncertainties that occur in the chain of steps between the intended and delivered radiation treatment, which includes imaging of the area of ​​interest, modeling of the tissue to be treated and surrounding the area of ​​interest, modeling of the radiation beam, treatment planning, setup and positioning of the radiation treatment device, and finally the actual spatiotemporal delivery of the radiation beam.

[0012] As mentioned above, various quality assurance systems are used to control and calibrate radiation therapy treatments, taking into account some of the errors and uncertainties mentioned above. Some quality assurance devices, at least in the literature, are intended to measure radiation beams during treatment, while others are primarily used in factory or pre-treatment environments for calibration of radiation therapy devices prior to treatment. However, such devices typically do not take into account the actual treatment environment, such as the radiation therapy machine, couch, and gantry components. However, the actual treatment environment can affect the radiation beam treatment and its measurements.

[0013] Installing and setting up quality assurance systems in conventional systems can be complex and time-consuming, not only adding cost but also making it difficult to implement quality assurance (QA) systems during or immediately prior to treatment. Similarly, performing constancy check measurements for QA purposes or assessing the correctness of a treatment planning system's target modeling from many different beam directions is time-consuming and requires the use of multiple different measurement devices and many manual steps, especially when using third-party QA devices that are not mechanically integrated into the irradiation room or the treatment machine control system. Summary of the Invention [Problem to be solved by the invention]

[0014] One of the problems that the present invention aims to solve is to easily set up a QA system in an irradiation chamber without modifying the existing irradiation chamber equipment, and to enable delivery of a proton beam from virtually any angle.

[0015] In view of the above, it is an object of the present invention to provide a quality assurance system for particle radiation therapy that is quick and easy to implement while ensuring accurate calibration or verification of particle radiation therapy to identify or reduce errors and uncertainties between the intended and delivered dose distributions.

[0016] It would be advantageous to provide a quality assurance system for particle radiation therapy that is flexible and easily adaptable to a variety of beam delivery configurations and couches.

[0017] It would be advantageous to provide a quality assurance system for particle radiation therapy that is easy and economical to install and remove from the irradiation room, especially for conventional particle radiation therapy devices.

[0018] It would be advantageous to provide a detection system for a quality assurance system for particle radiation therapy that is compact, easy and quick to install and remove, and yet allows for accurate measurement of target activation in a representative treatment environment. [Means for solving the problem]

[0019] The object of the present invention has been achieved by providing a system according to the independent claims. The dependent claims define various advantageous features of embodiments of the invention.

[0020] Disclosed herein is a quality assurance system for radiation therapy used in a treatment apparatus including a treatment couch and a particle radiation device having a radiation emitter head for particle beam radiation, the quality assurance system comprising: a detector device including at least one detection module configured to measure gamma radiation emitted by a target object receiving the particle radiation beam; a support mechanism to which at least one detection module is mounted, the support mechanism including a base configured to be removably coupled to a treatment table of the treatment device, and at least one detection module support structure pivotally coupled to the base via a pivot connection; Includes:

[0021] In an advantageous embodiment, the detection module support structure has a substantially C-shaped configuration with an open section configured to allow a particle radiation beam emitted by a radiation emitter of the particle radiation device to pass through the open section.

[0022] In one embodiment, the detection module support structure has at least two open sections configured to allow a particle radiation beam emitted by a radiation emitter of the particle radiation device to pass through the open sections.

[0023] In an advantageous embodiment, the open section, or at least one of the open sections, may advantageously have a width greater than the width of the treatment table so that the detector module can be mounted vertically around the treatment table.

[0024] In an advantageous embodiment, the support mechanism includes a support arm that connects the detection module support structure to the pivot connection and positions the detection module support structure relative to the pivot connection so that the central axis of the support structure is aligned with the rotation axis of the pivot connection.

[0025] In an advantageous embodiment, the pivot connection includes a motor configured for motorized rotation of the detection module about the axis of rotation of the pivot connection.

[0026] In an advantageous embodiment, the support mechanism of the detector apparatus further includes a sliding linkage configured to translate the pivot base of the pivot linkage relative to the base, the sliding linkage or instance including a rail on the base that engages with a complementary rail or channel on the pivot base.

[0027] In an advantageous embodiment, the system further includes a detector transport device including a carriage having a support surface for removably mounting the detector device thereon, the carriage having ground engaging members, e.g., in the form of wheels or rollers, configured to position the detector device for coupling to the treatment device, and which enable displacement of the carriage to and away from the treatment device.

[0028] In an advantageous embodiment, the carriage of the detector transport device includes a position adjustment mechanism for moving the detector device onto or off a support surface of the carriage.

[0029] In an advantageous embodiment, the system further includes a lift mechanism for transferring the detector device from the cart onto the treatment table.

[0030] In an advantageous embodiment, the system further includes an adapter interface mountable on a couch of the treatment device, the detector device being mountable on the adapter interface for coupling to the couch.

[0031] In an advantageous embodiment, the adapter interface and the carriage have interengaging locking elements for storing the adapter interface on the carriage when not in use.

[0032] In an advantageous embodiment, the carriage includes guard rails that receive the ends of the detection module support structure therein to protect the detection modules when the detector device is mounted and stored on the detector transport device.

[0033] In an advantageous embodiment, the system further includes a phantom device comprising a body made of or including a material selected from any one or more of polyethylene (PE), HE solid water, virtual water, RW1, RW3, polystyrene, blue water or polymethyl methacrylate (PMMA), or other low-Z materials comprising generally short-lived radioactive isotopes produced by the beam or isotopes that have a high probability of emitting positrons after interaction with the radiation beam, such as 18O, 63Cu, or 68Zn, and one or more cavities formed within the body.

[0034] In advantageous embodiments, the cavity of the phantom device comprises a bore and / or a slot, which may include transverse and axial slots, formed in the material of the body.

[0035] In an advantageous embodiment, the phantom device includes a front surface that is substantially planar and a side surface that is substantially perpendicular to the top or front surface and connected to the top or front surface via a chamfered or rounded corner.

[0036] In an advantageous embodiment, the side surface is substantially cylindrical or polygonal.

[0037] In an advantageous embodiment, the system further comprises a computing system connectable to the detector device for obtaining measurement data from the detection module and for controlling the detector device.

[0038] In an advantageous embodiment, the computing system is configured to output at least one distal fall-off coordinate of the measured activation, the distal fall-off coordinate corresponding to a falling edge of the measured activation along the particle beam axis.

[0039] In an advantageous embodiment, the computing system is configured to output coordinates of at least one rising edge of the measured activation, the rising edge coordinate corresponding to a point of incidence of the particle beam on the irradiated target.

[0040] Also disclosed herein is a treatment device in combination with a quality assurance system for radiation treatment according to any preceding embodiment, wherein, in use, a detector device is mounted on a treatment table of the treatment device, a radiation emitter head of the treatment device is positioned for transmission of a particle radiation beam through an opening in the detection module support structure, and the position of the detection module support structure is adjusted to align with the radiation emitter head through the opening in the support structure.

[0041] In an advantageous embodiment, the detection module support structure is positioned within a tunnel of the treatment device in which the radiation emitter head is mounted.

[0042] In an advantageous embodiment, the detection module support structure is dynamically coupled to the base and configured to rotate synchronously with the radiation emitter head of the treatment device.

[0043] In an advantageous embodiment, a computing system of a quality assurance system for radiation therapy is connected to at least one of a treatment planning system module and a beam delivery system of a treatment device to receive information regarding the target, the treatment plan, the irradiation progress, and log files from the irradiation session.

[0044] Further objects and advantageous features of the present invention will become apparent from the appended claims, detailed description and accompanying drawings. [Brief explanation of the drawings]

[0045] [Figure 1] FIG. 1 is a block diagram of a quality assurance system for radiation therapy according to an embodiment of the present invention. [Figure 2a]1 is a schematic representation of a treatment apparatus showing an accelerator, magnetic elements of a rotating gantry, a radiation emitter head including a monitor, a scanned particle beam, and a phantom device on a treatment table. [Figure 2b] 1 is a perspective view of a detector apparatus of a quality assurance system for radiation therapy according to an embodiment of the present invention installed in a conventional treatment apparatus including a treatment couch and a particle radiation device. [Figure 3a] 1 is a perspective view of a detector device of a quality assurance system for radiation therapy according to an embodiment of the present invention; [Figure 3b] 3a, showing the detection module and support structure of the detector device in a position rotated and translated relative to the base as compared to the position in FIG. 3a; [Figure 3c] 1 is a schematic representation of a detector arrangement seen in the direction of the rotation axis of the detector module. [Figure 3d] 1 is a perspective view of a detector apparatus having two detection modules, where the support structure is configured to have two open sections between the detector modules according to one embodiment of the present invention. [Figure 4a] 1 is a perspective view of a detector transport device of a quality assurance system for radiation therapy according to an embodiment of the present invention. [Figure 4b] 1 is a perspective view of a detector transport device of a quality assurance system for radiation therapy according to an embodiment of the present invention. [Figure 5a] 3a-3c mounted on the detector carrier of FIGS. 4a and 4b, and a perspective view of an examination table on which the detector carrier is positioned. FIG. [Figure 5b] FIG. 1 is a perspective view of an examination table and an adapter interface of a detector device mounted thereon, according to one embodiment of the present invention. [Figure 5c] 1 is an exploded perspective view of a detector device mounted on a treatment table with an adapter interface therebetween, according to one embodiment of the present invention; FIG. [Figure 6a] FIG. 1 is a perspective view of a phantom device of a quality assurance system for radiation therapy according to an embodiment of the present invention. [Figure 6b] 1 is a simplified schematic diagram of a phantom device and associated graphs showing the intensity of activation over the length of the phantom device with a cavity formed therein, and the corresponding rising edges and fall-off points along the beam trajectory. [Figure 7a] FIG. 1 is a block flow diagram illustrating steps for acquiring measurement data in a quality assurance system for radiation therapy according to an embodiment of the present invention. [Figure 7b] FIG. 1 is a simplified block flow diagram illustrating steps for checking the consistency of measurements performed by a quality assurance system for radiation therapy according to an embodiment of the present invention. [Figure 8] FIG. 7b is a block flow diagram similar to FIG. 7a further illustrating the analysis and output steps in a quality assurance system for radiation therapy according to one embodiment of the present invention. [Figure 9] FIG. 2 is a block flow diagram illustrating an example of steps for processing measurements of penetration depth of a particle beam in a target object according to an embodiment of the present invention. [Figure 10] FIG. 10 is a view similar to FIG. 9 of a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0046] 1 and 2, there is shown a quality assurance system 2 for radiation therapy according to one embodiment of the present invention for use with a treatment device 100. The quality assurance system 2 for radiation therapy includes a detector device 3 including a detection module 8, and a computing system 4 connectable to the detection module for acquisition and analysis of measurement data output by the detection module.

[0047] The computing system 4 may further include a control module for controlling and configuring the detector device and the data acquisition process. The computing system may further include a user interface and a module for image reconstruction for visualizing the therapeutic dose and related quantities, such as distribution, activation or stopping power, within the target body.

[0048] The computing system may further include or be connected to a database, a beam delivery system (BDS) 107, and a treatment planning system (TPS) 108 containing information about the target to be treated and the radiation beam delivery plan. The TPS includes software used to generate a treatment plan, which may typically include a list of proton beam spots to be delivered based on available target information. The TPS is separate from the control system that controls the beam delivery system and irradiation. Thus, the computing system may be connected to the treatment planning system, which provides information about the target and may be used to generate the treatment plan, and to the beam delivery system of the therapy device 100, which executes and monitors the treatment planning delivery process, including controlling the particle radiation device 103 for delivery of radiation therapy to the patient or target.

[0049] The treatment apparatus can have various configurations according to treatment apparatuses known per se. In the illustrated embodiment, the treatment apparatus comprises a treatment table 101, also known as a patient treatment table, which may be mounted on a robotic arm 102, and a particle radiation device 103 including a particle accelerator 112, a gantry 105 with magnets 109 for guiding, focusing and deflecting the beam, and a radiation emitter head 104 including a beam monitor 110.

[0050] In a variant, the couch 101, via the robotic arm 102, can have up to six degrees of freedom of translation and rotation (pitch, roll, yaw) in three dimensions, independent of the gantry 105, allowing irradiation of a patient or target placed on the couch 101 from various directions by adjusting the position and orientation of the couch 101 and the angle of the gantry about the rotation axis B. In another variant, the radiation device 103 does not include a gantry, and the radiation emitter head 104 is fixed, providing, for example, a horizontal or vertical beam into the irradiation chamber. Other combinations of relative motion are also possible, for example, mounting the accelerator 112 directly on a rotating structure.

[0051] 2a to 5b more specifically, the quality assurance system 2 for radiation therapy according to one embodiment of the present invention may further include a detector transport device 5 for moving the detector device 3 into and out of the treatment environment, for example, the treatment device 100 or the irradiation room.

[0052] The detector transport device 5 includes a carriage 9 mounted on wheels 27 that include an upper support surface or rails or other support elements to which the detector device can be mounted when the detector device is not installed within the treatment device 100.

[0053] The quality assurance system 2 for radiation therapy according to an embodiment of the present invention may advantageously further comprise a phantom device 6, which may be used to perform measurements and acquire data from the particle radiation beam emitted by the particle radiation device 103 of the therapy apparatus 100. The phantom device is made of a material and includes features intended to simulate a patient's body part and / or provide a specific target reference body that allows, in particular, an estimation of the behavior of the particle radiation beam at the body part of a living subject under treatment.

[0054] The detector device 3 includes one or more detection modules 8 mounted on a support mechanism 7 .

[0055] The detection module 8 is configured to measure secondary radiation emitted by a target subjected to particle radiation, the secondary radiation being mainly in the form of gamma rays.

[0056] Gamma ray detection modules are known per se and may in the present invention advantageously include configurations and features as described in WO2021140233. Other gamma ray detection modules known per se in the art may also be used within the scope of the present invention.

[0057] In one embodiment, the detection modules 8 are advantageously arranged in a ring around a central axis. In a preferred embodiment, as shown in Figures 3a-3c, the ring has an opening so as to form a substantially C-shape, which opening allows the radiation emitter head 104 of the particle radiation device 103 to emit the particle radiation beam 111 through the opening.

[0058] In another embodiment, the detection modules may be arranged to provide openings on both sides that allow the radiation emitter heads 104 of the particle radiation device 103 to emit the particle radiation beam 111 through the openings. For example, in the embodiment shown in Figure 3d, at least one pair of detection modules 8 are positioned on the support mechanism 7 in a spaced apart opposing relationship, leaving openings on both sides (top and bottom as shown).

[0059] For treatment plans that include relative rotation of the radiation head about the central axis, the detection module support structure 18 is configured to rotate to align the opening of the ring with the position of the particle radiation beam, in other words, the position of the radiation emitter head 104.

[0060] In a treatment device 100 including a tunnel surrounding a treatment table 101 around which the radiation emitter head 104 can move, the outer diameter D of the detection module support structure 18 in which the detection module 8 is mounted is out is configured to fit within the tunnel of the treatment device 100.

[0061] Inner diameter D of detection module support structure 18 in may be advantageously configured to surround the treatment table 101 which may be received within the inner diameter of the detection module support structure.

[0062] The detection module opening has a width of D gap which may advantageously be configured to exceed the width of the treatment table 101 in order to mount the detector device on the treatment table 101 in a direction perpendicular to the treatment table surface, as shown in Figure 5c.

[0063] The support mechanism 7 of the detector apparatus includes a base 12 to which a support arm 14 is movably connected, and a detection module support structure 18 is fixed to the support arm 14. The support arm 14 may advantageously be connected to the base via a pivot connection 16 having a center of rotation corresponding to a central axis A of the detection module support structure 18, such that as the support arm 14 pivots about the pivot connection 16, the detection module support structure 18 undergoes circular movement within its own envelope. The support mechanism 7 may advantageously further include a slide connection 19, for example comprising a rail mounted on the base 12, configured to translate a pivot base 17 of the pivot connection 16 in the axial direction A. Thus, the detection module 8 may be rotated circularly about the central axis A and further translated in the direction of the central axis. This translational movement allows for precise axial positioning of the detection module over the target area, and also allows for corresponding translational movement of the detection module 8 if the radiation emitter head 104 or the treatment table 101 are axially translatable relative to the central axis A. The translational movement also facilitates access or an unobstructed view of the target as needed, for example when the target is imaged in situ with orthogonal X-ray panels.

[0064] The radiation emitter head, or an element thereon, such as a range shifter, may also be translatable in the beam direction to reduce the gap between said element and the target, advantageously removing said gap from the detection module support structure 18 and support arm 14, thereby enabling beam delivery with minimal gap.

[0065] The pivot connection 16 preferably includes a motor for electrically actuating the rotation of the detection module 8. The sliding connection 19 may also include an electrically actuated device, such as a linear nut and screw actuator, for translating the detection module 8 relative to the base 12.

[0066] In a variant, the pivot connection and / or sliding connection may be entirely mechanical and manually operable, particularly for use with a particle radiation device 103 having a radiation emitter head 104 that does not move dynamically during particle beam emission.

[0067] In an alternative embodiment, the multiple detection modules may be independently movable, for example, by an independently pivoting support structure or by multiple articulating positioning arms.

[0068] The detector device advantageously includes a support mechanism 7 with a base 12 that enables the detector device to be connected to, in particular mounted on, the treatment table 101 in the treatment environment, i.e. in a position corresponding to the position of treatment of the patient within the treatment device 100.

[0069] The quality assurance system for radiation therapy may advantageously further include an adapter interface 20 forming an interface between the base 12 of the detector device 3 and the treatment couch 101, the adapter interface 20 being configured to adapt the position of the base 12 relative to the adapter interface 20 via a base positioning element 32. The adapter interface may include a fixing member 35 for fixing the adapter interface to the treatment couch 101, whereby different fixing members for different standards of treatment couches can be provided and the detector device 3 can be connected to different treatment couches 101 without changing the base 12.

[0070] In the illustrated embodiment, the treatment table 101 includes position markers or fixing elements 106 on its side edges, which allow for positioning and alignment of the patient and / or adapter interface 20 relative to the particle radiation device 103 and / or robotic arm 102.

[0071] The carriage 9 may advantageously include elements for fastening and storing the adapter interface 20 on the carriage, for example conveniently on the side of the carriage.

[0072] The dolly 9 may include a cabinet compartment 34 for storing various components of the quality assurance system 2 for radiation therapy, and may further have space for supporting the computing system 4 and storing one or more phantom devices 6. The dolly may also support a power source such as a battery or may be provided with a plug and / or cable for connecting to a power source, for example to connect to the detector apparatus 3.

[0073] The carriage 9 may further include a displacement mechanism 25, e.g., including a height adjustment mechanism and optionally a translation mechanism, for moving the detector device 3 of the carriage 9 from or onto the couch 101. Prior to such movement, the adapter interface 20 may be mounted on the couch 101, as shown in Figure 5b.

[0074] The cart 9 may further include an electrically or manually operable lift mechanism (height adjustment mechanism) for lifting the detector device 3 from the cart onto the treatment table 101. Alternatively, the treatment table 101 may have a lift mechanism for adjusting the height of the treatment table, which may also be used to lift the detector device 3 from the cart onto the treatment table 101. In a variant, both the treatment table and the cart may have their own lift mechanisms.

[0075] When the detector apparatus 3 is mounted on the dolly 9 for storage or when not in use, the detector module support structure 18 can be positioned in a stowed position as shown in Figure 5a, with the open end of the detector module support structure 18 positioned within a guard rail 23 that provides protection for the support structure on the dolly.

[0076] A phantom device 6 according to an advantageous embodiment of the present invention includes a body 22 of material, preferably having a low average atomic number, and a plurality of cavities 24, which may include bores 26 and / or slots 28, formed in the body of material. The material of the phantom device 6 may include any one or more of commonly used phantom materials, such as polyethylene (PE), HE solid water, virtual water, RW1, RW3, polystyrene, plastic water, blue water, or polymethyl methacrylate (PMMA), or other materials with generally short-lived radioactive isotopes produced by the beam. The phantom device may also be made of a material containing a high concentration of isotopes, such as fluorine, that have a high probability of emitting positrons after interaction with the proton beam. 18 O. 63 Cu or 68Zn. The slots 28 may include transverse slots 28a, axial slots 28b, or slots having both axial and transverse components (not shown). The body 22 may have a top or front surface 30 and a side surface 31, which may have, for example, a generally cylindrical shape, although other non-axisymmetric or polygonal shapes may also be provided. The front or top surface 30 may be joined to the side surface 31 via a rounded or chamfered corner 33. Both the front surface and the chamfered or rounded corner surface may comprise cavities formed within the body of material.

[0077] Cavity 24 forms a region where the particle radiation beam has negligible energy loss and can thus serve as a spatial reference zone in measurements of secondary radiation resulting from the interaction of the particle radiation beam with the material of body 22, and can be configured with various sizes, geometries, and densities to tailor the properties of the phantom device to the particle radiation beam passing therethrough. In a variation, it is possible to have phantom devices with various material structures, including materials with different compositions and / or densities formed together in layers or other three-dimensional structures, for example, formed by additive manufacturing such as 3D printing, to more closely simulate a target object, e.g., a body part containing a treatment target region.

[0078] Therefore, the diameter or width of the features of the phantom device 6 can be advantageously selected to provide maximum sensitivity to beam displacement from its intended position or to the relative displacement between two or more irradiation sessions being compared. This can be achieved, for example, by selecting the bore diameter so that the edge of the bore is aligned with the maximum gradient of the beam's transverse profile. For a Gaussian beam profile, this corresponds to a 2σ width or diameter. The beam width can depend on the beam energy. For this reason, the phantom can advantageously feature bores with a range of diameters, so that sensitivity to displacement can be maximized by selecting an appropriate bore for the beam energy of interest.

[0079] The phantom device 6 may also incorporate an internal cavity 24, as shown schematically in Figure 6b.

[0080] The material near the bore, slot or cavity may advantageously be enriched with one or more isotopes selected to increase the available signal for imaging.

[0081] A cavity can be advantageously used to increase sensitivity to axial displacement of the beam 111, i.e., deviations in beam penetration depth. The beam energy can be selected so that its deepest attenuation length region coincides with the proximal or distal surface of the cavity or recess. In a preferred embodiment, the intended maximum gradient of the deepest attenuation length coincides with the proximal or distal cavity surface. Changes in beam energy can be measured as an increase or decrease in total activation detected downstream of the cavity or recess, as shown in Figure 6b.

[0082] It is advantageous to define the exact dimensions and materials of the phantom device 6 and the intended beam trajectory so that the intended beam range matches any beam energy available for clinical or quality assurance purposes. In a preferred embodiment, the surfaces of the beam entry point and the distal and proximal boundary surfaces of the cavities or recesses along the beam trajectory are preferably all parallel to each other and orthogonal to the beam axis to avoid correlation of target activation upstream or downstream of any cavity or recess to even minor unintended beam position displacements.

[0083] The phantom device 6 can be reproducibly positioned on the couch using a docking structure similar to the adapter interface 20 that can be conveniently aligned with the couch position markers 106, thereby limiting uncertainty in the positioning of the phantom device relative to the couch. In one embodiment of the present invention, the adapter interface 20 extends from the base 12 along the couch 101 and also serves as a docking structure or support for the target.

[0084] A method for performing a constancy check according to one embodiment of the present invention is shown in FIG. 7a. A preferred embodiment of this method uses two or more independent irradiation sessions, performed routinely, for example, for comparison with a baseline acquisition, or before and after maintenance or modification of the treatment device. This method can advantageously be performed using a phantom device 6 to increase sensitivity to changes in beam characteristics or the alignment of system components. For each irradiation session, the target is prepared in an appropriate manner. Depending on the target used, preparation may involve, for example, filling a water tank or immobilizing the tissue target. Target imaging can be performed to plan the beam delivery sequence. The treatment room, target, and detector device 3 are then set up for the irradiation session. The radiation beam is delivered according to the prepared sequence, and measurements are obtained using the detector device 3. The detector device 3 can advantageously take beam delivery parameters as input to calculate a translation scheme. Alternatively, the detector device 3 can implement a pre-defined translation scheme that provides sensitivity to the entire target volume or a volume of interest.

[0085] While the phantom device 6 can be used as a constant target to improve the measurement accuracy of the constancy check, the detector device 3 can also be advantageously used to evaluate uncertainties in TPS modeling of other targets, such as tissue samples or animal body parts. As an example, the TPS can be used to construct a model of a target and a treatment plan to be delivered within the target. The simplest executable treatment plan consists of a single beam spot. During or after delivery of the treatment plan, the computing system 4 can generate one-dimensional, two-dimensional, or three-dimensional images, possibly including time-dependent information (space-time), of the target activation detected by the detector device 3. The computing system 4 can output at least one deepest attenuation length coordinate 113 of the measured activation, where the deepest attenuation length coordinate corresponds to the trailing edge of the measured activation along the beam axis. This deepest attenuation length point can be associated with a residual beam energy corresponding to the cutoff energy for production of the radioisotope being imaged by the detector device. The computing system 4 can also output the coordinates of at least one rising edge 114 of the measured activation so as to provide an independent means of identifying the position of the target relative to the detector device 3, the rising edge corresponding to the beam incidence point or the surface of the irradiated target.

[0086] The deepest attenuation length method described above can be extended to examine residual beam energy along the beam axis by measuring at varying beam energies. In this case, it is advantageous to define a sequence of beam spots sufficiently spaced within the target to allow resolution of individual attenuation lengths. This can be achieved, for example, by using an ascending order of beam energies so that the attenuation length of each spot can be resolved from the residual activity of the previous beam spot. The finite decay period of the activated isotope can be exploited by delivering beam spots separated by a sufficient time interval to allow spatially overlapping distributions to substantially decay. This method can also be used with a scanned field of beam spots to estimate residual beam energy at locations on the beam scan plane.

[0087] The above-described methods can be combined to examine the residual beam energy within a target as a function of position in one, two, or three dimensions. This can be achieved, for example, by defining a sequence of energy- and coordinate-defined layered beam spots in a beam scanning plan, such that each energy layer, or the deepest attenuation length of each layer, can be resolved for each point in the scan plane.

[0088] Residual beam energy measurements obtained from the previously described method can be compared with values ​​calculated by existing treatment planning solutions to verify the target modeling assumed by these existing solutions. One embodiment of a process for performing a treatment planning system (TPS) evaluation is shown in Figures 8, 9, and 10. The detector device 3 provides measurements of the deepest attenuation length position z_cutoff. The initial energy E_0 is assumed to be known from the beam delivery configuration, and the threshold energy for target activation E_cutoff is assumed to be known from the literature. The TPS provides calculations of the residual beam energy at a specified depth z_cutoff or the depth to achieve a specified residual beam energy E_cutoff. Evaluation of the consistency between the TPS calculations and measurements is possible using either quantity. The calculation of these quantities by the TPS relies on estimates of the stopping power integral, which incorporates a model of the beam delivery system, the target, and the beam particle interactions within the target. Therefore, comparison of the quantities calculated by the TPS with those measured by the detector device 3 provides an evaluation of the accuracy of modeling of these aspects relevant to clinical treatment planning.

[0089] Because the imaged activity endpoint is proximal to the peak dose deposition and the beam range, the distal activity falloff is not sensitive to material variations at the distal end of the beam range. Therefore, it is advantageous to modify the treatment plan to expand the interrogated volume. For example, the treatment plan can be modified to include higher energies than those used in the proposed clinical treatment. In this way, the validity of modeling assumptions can be examined throughout the target volume relevant to the dose deposition plan. Similarly, the number of particles per spot can be advantageously increased beyond that appropriate for clinical practice, thereby increasing target activation to provide sufficient statistics to generate images of the desired quality.

[0090] [List of references used] treatment equipment 100 Treatment table (patient treatment table) 101 Location Marker 106 Robot Arm 102 Particle Radiation Devices 103 Accelerator 112 Gantry 105 Magnet 109 Radiation emitter head 104 Beam Monitor 110 Particle Beam 111 Beam Delivery System 107 Treatment Planning System 108 Quality Assurance System for Radiation Therapy 2 Detector device 3 Support mechanism 7 Base 12 Support arm 14 Pivot connection 16 Pivot Base 17 Slide connection part 19 rail Detection module support structure 18 Detection Module 8 Computing System 4 Attenuation point 113 Rising Edge 114 Detector transport device 5 Cart 9 Guardrail 23 Height adjustment mechanism 25 Wheels 27 Cabinet Room 34 Adapter Interface 20 Base Positioning Element 32 Medical table fixing element 35 Phantom Device 6 Main body 22 Material PMMA,... Cavity 24 Bore 26 Slot 28 Transverse 28a Axial direction 28b Top surface 30 Side 31 Chamfers, rounded corners33 Axial center axis A Gantry rotation axis B

[0091] [Embodiment] (1) A quality assurance system (2) for radiation therapy used in a treatment apparatus (100) including a treatment table (101) and a particle radiation device (103) having a radiation emitter head (104) for particle beam radiation, the system comprising: a detector device (3) including at least one detection module (8) configured to measure gamma radiation emitted by a target object subjected to a particle radiation beam; a support mechanism (7) on which the at least one detection module (8) is mounted, the support mechanism (7) including a base (12) configured to be removably coupled to a treatment table (101) of the treatment device (100), and at least one detection module support structure (18) pivotally coupled to the base (12); Quality assurance system, including: (2) The system described in embodiment 1, wherein the detection module support structure (18) has a substantially C-shaped shape with an open section, and the open section is configured to allow a particle radiation beam emitted by a radiation emitter (104) of the particle radiation device (103) to pass through the open section. (3) The open section has a width (D) greater than the width of the treatment table (101). gap 3. The system of claim 2, further comprising: (4) The system described in embodiment 1, wherein the detection module support structure (18) has at least two open sections, and the at least two open sections are configured to allow a particle radiation beam emitted by a radiation emitter (104) of the particle radiation device (103) to pass through the open sections. (5) At least one of the at least two open sections has a width (D) greater than the width of the treatment table (101).gap 5. The system of claim 4, wherein

[0092] (6) A system described in any one of embodiments 1 to 5, wherein the support mechanism (7) includes a support arm (14) that connects the detection module support structure (18) to the pivot connection portion (16) and positions the detection module support structure (18) relative to the pivot connection portion (16) so that the central axis of the detection module support structure is aligned with the rotation axis of the pivot connection portion. (7) A system described in any one of embodiments 1 to 6, wherein the pivot connection (16) includes a motor configured for motorized rotation of the detection module about the rotation axis (A) of the pivot connection (16). (8) A system described in any one of embodiments 1 to 7, wherein the support mechanism (7) of the detector device (3) further includes a sliding connection (19) configured for translational movement of at least the detection module support structure (18), for example including a rail on the base (12) that engages with a complementary rail or channel on the pivot base (17). (9) The system of any of the preceding claims, further comprising a detector transport device (5) including a carriage (9) having a support surface for removably mounting the detector device thereon, the carriage (9) having ground-engaging members, e.g., in the form of wheels (27) or rollers, configured to position the detector device (3) for coupling to a treatment device, and enabling displacement of the carriage towards and away from the treatment device. (10) The system of embodiment 9, wherein the carriage (9) of the detector transport device includes a position adjustment mechanism (25) for moving the detector device on or off the support surface of the carriage (9).

[0093] (11) The system described in embodiment 9 or 10, wherein the dolly includes a guard rail (23) that receives the end of the detection module support structure (18) therein to protect the detection module when the detector device (3) is mounted and stored on the detector transport device (5). (12) The system according to any one of embodiments 9 to 11, further comprising a lift mechanism for transferring the detector device (3) from the cart (9) onto the examination table (101). (13) The system described in any one of embodiments 1 to 12, further comprising an adapter interface (20) mountable on a treatment table (101) of the treatment device (100), wherein the detector device (3) is mountable on the adapter interface (20) for connection to the treatment table (101). (14) The system of claim 13 in combination with any of claims 9 to 12, wherein the adapter interface (20) and the carriage (9) have interengaging fastening elements for storing the adapter interface (20) on the carriage when not in use. (15) Polyethylene (PE), HE solid water, virtual water, RW1, RW3, polystyrene, blue water, or polymethyl methacrylate (PMMA), or generally short-lived radioisotopes produced by said beams, or 18 O. 63 Cu, or 68 A system as described in any one of embodiments 1 to 14, further comprising a phantom device (6) comprising a body (22) made of or containing a material selected from one or more of other low-Z materials, such as Zn, having an isotope that has a high probability of emitting positrons after interaction with the radiation beam (111), and one or more cavities (24) formed within the body.

[0094] (16) The system of embodiment 15, wherein the cavity of the phantom device includes a bore (26) formed in the material of the body and / or a slot (28) which may include a transverse slot (28a) and an axial slot (28b). (17) The system of embodiment 15 or 16, wherein the phantom device includes a front surface (30) that is substantially planar, and a side surface (31) that is substantially perpendicular to the top or front surface and connected to the top or front surface via a chamfered or rounded corner surface (33). (18) The system of embodiment 17, wherein the side surface (31) is substantially cylindrical or polygonal. (19) The system of any one of claims 1 to 18, further comprising a computing system (4) connectable to the detector device (3) for acquiring measurement data from the detection module (8) and for controlling the detector device. (20) A system described in any one of embodiments 1 to 19, wherein the computing system (4) outputs at least one deepest attenuation length coordinate of the measured activation, the deepest attenuation length coordinate corresponding to a falling edge of the measured activation along the beam axis.

[0095] (21) The system of any one of embodiments 1 to 20, wherein the computing system (4) outputs coordinates of at least one rising edge of the measured activation, the rising edge coordinates corresponding to an incident point of the irradiated target. (22) A treatment device (100) in combination with a quality assurance system for radiation therapy according to any one of the preceding claims, comprising: In use, the detector device (3) is mounted on the treatment table (101) of the treatment device, the radiation emitter head (104) of the treatment device is positioned for transmission of a particle radiation beam through the opening in the detection module support structure (18), and the position of the detection module support structure is adjusted to align with the radiation emitter head (104) through the opening in the support structure (18). (23) The combination described in embodiment 22, wherein the detection module support structure is dynamically coupled to the base (12) and configured to rotate synchronously with the radiation emitter head (104) of the treatment device (100). (24) The combination described in embodiment 22 or 23, wherein the computing system (4) of the quality assurance system (2) for radiation therapy is connected to at least one of a treatment planning system module and a beam delivery system of the treatment device (100) to receive information about the target, the treatment plan, the irradiation progress, and a log file from the irradiation session.

Claims

1. A quality assurance system (2) for radiation therapy used in a treatment apparatus (100) including a treatment couch (101) and a particle radiation device (103) having a radiation emitter head (104) for particle beam radiation, comprising: a detector device (3) comprising at least one detection module (8) configured to measure gamma radiation emitted by a target object subjected to a particle radiation beam; a support mechanism (7) on which the at least one detection module (8) is mounted, the support mechanism (7) including a base (12) configured to be removably coupled to a treatment table (101) of the treatment device (100), and at least one detection module support structure (18) pivotally coupled to the base (12); Quality assurance system, including:

2. 2. The system of claim 1, wherein the detection module support structure (18) has a substantially C-shaped configuration with an open section, the open section being configured to transmit a particle radiation beam emitted by a radiation emitter (104) of the particle radiation device (103) through the open section.

3. The open section has a width (D) greater than the width of the treatment table (101). ｇａｐ 3. The system of claim 2, further comprising:

4. 2. The system of claim 1, wherein the detection module support structure (18) has at least two open sections, the at least two open sections being configured to transmit a particle radiation beam emitted by a radiation emitter (104) of the particle radiation device (103) through the open sections.

5. At least one of the at least two open sections has a width (D) greater than the width of the treatment table (101). ｇａｐ 5. The system of claim 4, further comprising:

6. 2. The system of claim 1, wherein the support mechanism (7) includes a support arm (14) that connects the detection module support structure (18) to the pivot connection (16) and positions the detection module support structure (18) relative to the pivot connection (16) so that the central axis of the detection module support structure is aligned with the rotation axis of the pivot connection.

7. 2. The system of claim 1, wherein the pivot connection (16) includes a motor configured for motorized rotation of the detection module about an axis of rotation (A) of the pivot connection (16).

8. 2. The system of claim 1, wherein the support mechanism (7) of the detector device (3) further comprises a sliding connection (19) configured for translational movement of at least the detection module support structure (18), for example comprising a rail on the base (12) that engages with a complementary rail or channel on the pivot base (17).

9. 2. The system of claim 1, further comprising a detector transport device (5) including a carriage (9) having a support surface for removably mounting the detector device thereon, the carriage (9) having ground engaging members, e.g. in the form of wheels (27) or rollers, configured to position the detector device (3) for coupling to a treatment device, and enabling displacement of the carriage towards and away from the treatment device.

10. 10. The system of claim 9, wherein the carriage (9) of the detector transport device comprises a position adjustment mechanism (25) for moving the detector device onto or from the support surface of the carriage (9).

11. The system of claim 9, wherein the carriage includes guard rails (23) that receive ends of the detection module support structure (18) therein to protect the detection module when the detector device (3) is mounted and stored on the detector transport device (5).

12. The system according to claim 9, further comprising a lift mechanism for transferring the detector device (3) from the carriage (9) onto the treatment table (101).

13. 2. The system of claim 1, further comprising an adapter interface (20) mountable on a treatment table (101) of the treatment device (100), wherein the detector device (3) is mountable on the adapter interface (20) for connection to the treatment table (101).

14. 14. The system of claim 13 in combination with any one of claims 9 to 12, wherein the adapter interface (20) and the carriage (9) have interengaging locking elements for storing the adapter interface (20) on the carriage when not in use.

15. Polyethylene (PE), HE solid water, virtual water, RW1, RW3, polystyrene, blue water or polymethyl methacrylate (PMMA), or a generally short-lived radioisotope produced by said beam, or １８ O. ６３ Cu, or ６８ 2. The system of claim 1, further comprising a phantom device (6) comprising a body (22) made of or containing a material selected from any one or more of other low-Z materials, such as Zn, having isotopes that have a high probability of emitting positrons after interaction with the radiation beam (111), and one or more cavities (24) formed in the body.

16. 16. The system of claim 15, wherein the cavity of the phantom device includes a bore (26) formed in the material of the body and / or a slot (28) which may include a transverse slot (28a) and an axial slot (28b).

17. 16. The system of claim 15, wherein the phantom device includes a substantially planar front surface (30) and a side surface (31) that is substantially perpendicular to the top or front surface and connected to the top or front surface via a chamfered or rounded corner surface (33).

18. 18. The system of claim 17, wherein the side surface (31) is substantially cylindrical or polygonal.

19. 2. The system of claim 1, further comprising a computing system (4) connectable to the detector device (3) for obtaining measurement data from the detection module (8) and for controlling the detector device.

20. 2. The system of claim 1, wherein the computing system outputs at least one innermost attenuation length coordinate of the measured activation, the innermost attenuation length coordinate corresponding to a falling edge of the measured activation along the beam axis.

21. 2. The system of claim 1, wherein the computing system outputs coordinates of at least one rising edge of the measured activation, the rising edge coordinates corresponding to an incidence point of the illuminated target.

22. A treatment device (100) in combination with a quality assurance system for radiation therapy according to claim 1, comprising: In use, the detector device (3) is mounted on the treatment table (101) of the treatment device, the radiation emitter head (104) of the treatment device is positioned for transmission of a particle radiation beam through an opening in the detection module support structure (18), and the position of the detection module support structure is adjusted to align with the radiation emitter head (104) through the opening in the support structure (18).

23. 23. The combination of claim 22, wherein the detection module support structure is dynamically coupled to the base (12) and configured to rotate synchronously with the radiation emitter head (104) of the treatment device (100).

24. 23. The combination of claim 22, wherein the computing system (4) of the quality assurance system (2) for radiation therapy is connected to at least one of a treatment planning system module and a beam delivery system of the treatment device (100) to receive information about the target, the treatment plan, the irradiation progress, and a log file from the irradiation session.

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