The following relates generally to the radiation therapy arts, radiation therapy planning arts, and related arts.
In radiation therapy, a patient is disposed on a table or other patient support in a treatment delivery room which also contains a linear accelerator (linac) or other radiation therapy beam delivery device (e.g., for delivering a therapeutic x-ray, electron, or proton beam). The radiation delivery device is mounted on a gantry so as to be revolved around the patient. While embodiments in which the radiation delivery device moves respective to a stationary patient are most common and are described here as examples, in some variant designs the radiation delivery device is stationary and a robotic couch moves the patient. In a conventional “step-and-shoot” therapy delivery, the delivery device is rotated using the device gantry between angular therapy delivery positions, with radiation being applied at each delivery position. In continuous delivery modes such as Volumetric Arc Therapy (VMAT), the radiation beam is applied during continuous rotation of the delivery device via the gantry through a delivery arc. In 4 pi delivery modes, the radiation delivery device rotates via its gantry and the patient support is also moved, so as to provide still more freedom to fine-tune the radiation delivery profile. In any such design, the patient may be positioned on the table (or other patient support, such as seated in a chair) with various supporting devices such as knee boards, breast boards, vacuum sealed bags, or so forth. Additionally other devices may be located in the treatment room such as intravascular (IV) fluid delivery support poles, cameras, machine attachments such as cone-beam computed tomography (CT) imaging devices or flat-panel imagers, or the like for monitoring patient position during the therapy delivery, or performing other functions.
There is potential for collision between components in this complex arrangement of moving components. Such collisions may occur during setup, pre-treatment imaging, at therapy positions or as components transition between therapy positions. In addition to actual collisions, it may be desirable to maintain safety or comfort margins between components. For example, the patient may be uncomfortable or become claustrophobic if the radiation delivery device comes too close to the patient.
The following discloses a new and improved systems and methods that address the above referenced issues, and others.
In one disclosed aspect, a radiation therapy simulation or planning device is disclosed, including a computer, a display, and a non-transitory storage medium. Said medium stores instructions readable and executable by the computer to perform operations including: generating configurations of components including at least a radiation delivery device and a patient wherein each generated configuration of components defines positions of the components in a common coordinate system; for each configuration, computing proximities of pairs of components of the configuration and identifying a collision as any pair of components having a computed proximity that is less than a margin for the pair of components; and displaying on the display each identified collision.
In another disclosed aspect, a radiation therapy simulation or planning device is disclosed, including a computer and a non-transitory storage medium storing instructions readable and executable by the computer to perform operations including: generating configurations of components including at least a radiation delivery device and a patient wherein each configuration of components defines positions of the components in a common coordinate system; for each configuration, computing proximities of pairs of components of the configuration using ray tracing and identifying a collision as any pair of components having a computed proximity that is less than a margin for the pair of components; and updating the generated configurations to eliminate any identified collision.
In another disclosed aspect, a radiation therapy device includes a radiation therapy planning device as set forth in the immediately preceding paragraph and a radiation delivery device. The radiation delivery device is operative to deliver stepwise radiation therapy to the patient in accordance with the generated radiation therapy delivery plan. In continuous arc delivery embodiments, the radiation delivery device applies therapeutic radiation to the patient during traversal of an arc between successive control points of the sequence of control points. In stepwise delivery embodiments, the radiation delivery device applies therapeutic radiation to the patient at successive control points of the sequence of control points and does not apply therapeutic radiation to the patient during traversal between successive control points of the sequence of control points.
In another disclosed aspect, a radiation therapy planning method is disclosed. A radiation therapy delivery plan is generated using a computer. The plan comprises radiation delivery settings at a plurality of control points, and the radiation delivery settings are optimized respective to a set of dose objectives. Each control point is defined by a configuration of components including at least a radiation delivery device and a patient. The configuration of components defines positions of the components in a common coordinate system. For the configuration of each control point of the radiation therapy delivery plan and for each of a plurality of configurations between the control points traversed during execution of the radiation therapy delivery plan, proximities of pairs of components of the configuration are computed using three-dimensional surface models representing the components of the pair, and a collision is identified as any pair of components having a computed proximity that is less than a margin for the pair of components. The computing of the proximity and the identifying are performed by the computer. Each identified collision is displayed on a display.
One advantage resides in detecting potential collisions during the radiation therapy planning stage and optionally prior to the dose optimization computation.
Another advantage resides in providing early detection of unsafe or uncomfortably close approaches between components prior to the planning of the radiation therapy session.
Another advantage resides in providing automated adjustment of the sequence of control points (CPs) for use in generating an intensity modulated radiation therapy (IMRT) plan in order to avoid collisions or unacceptably close approaches between components.
Another advantage resides in providing visualization of the spatial arrangement of components during radiation therapy planning or earlier, e.g. after the patient computed tomography (CT) scanning is performed but prior to dose optimization. Earlier detection of collisions, e.g. in simulation, can for example allow the therapist to adjust the desired isocenter position (marking locations) for use in planning and delivery later on.
A given embodiment may provide none, one, two, more, or all of the foregoing advantages, and/or may provide other advantages as will become apparent to one of ordinary skill in the art upon reading and understanding the present disclosure.
The invention may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention.
With reference to
The electronic processor 10 may be programmed to perform IMRT (or other) dose optimization 20 for a sequence of control points (CPs) 22 to achieve a set of radiation dose objectives 24 usually expressed as an average or minimum dose to be delivered to a target region (e.g. a malignant tumor) and dose limits for one or more organs at risk (OARs). Manual generation of the CPs 22 may also be done by the planner. As is known in the art, the IMRT optimization typically receives as inputs the set of radiation dose objectives 24 and anatomical information, e.g. in the form of a intensity map of the patient generated from a planning image acquired by computed tomography (CT) imaging, magnetic resonance (MR) imaging, or the like. The planning image is typically segmented to identify regions of different tissues or organs; such segmentation may be manual (e.g., the oncologist defines the regions by drawing contours in the planning image), automated (e.g. using edge detection or other appropriate image processing), or semi-automated. Each CP 22 is defined by a configuration of components present in the radiation therapy laboratory during the radiation therapy session. These components include at least a radiation delivery device 30 and a patient 32 (disposed on a patient support 34), and may include other devices such as a conebeam computed tomography (CT) imager (including an x-ray source 36 and x-ray detector panel 37) that may be employed in the radiation delivery room to monitor the patient 32. The illustrative radiation delivery device 30 is a linear accelerator (linac) having a radiation delivery head or emission orifice 38 that outputs a therapeutic radiation beam (which may be an electron beam, x-ray beam, or so forth depending on the type of radiation therapy). For example, the illustrative radiation delivery device 30 could be a TrueBeam™ radiotherapy system (available from Varian Medical Systems), which includes four components that introduce salients: the radiation delivery head/arm assembly; side-positioned x-ray source and detector array components for an integrated conebeam computed tomography (CT) imager; and an accessory module (no analog shown in
The configuration defines the positions of the components at the control points (CPs) 22 in a common coordinate system. In standard radiation therapy the configuration may vary among successive control points (CPs) 22 due to rotation of the radiation delivery device 30 around the patient 32. In 4 Pi radiation therapy both the radiation delivery device 30 and the patient support 34 may move to provide a wider range of achievable configurations.
The IMRT dose optimization 20 typically operates by optimizing radiation delivery settings such as beam-on time, multi-leaf collimator (MLC) settings for shaping the beam, and so forth at each control point so that the cumulative dose delivered to the target region and any OARs satisfies the set of radiation dose objectives 24. In a stepwise radiation therapy session the radiation is delivered only at the control points, with the radiation delivery head 38 held stationary at each control point (CP) 22. In continuous arc delivery approaches such as Volumetric Arc Therapy (VMAT), the radiation beam is applied during continuous rotation of the radiation delivery device 30 via its gantry through a delivery arc, and the number of control points (CPs) 22 is chosen to be high enough so that the radiation delivery settings can be interpolated between control points (CP) 22 to control delivery continuously over the continuous arc. It is also noted that while the single delivery head 38 is illustrated, in other embodiments there may be two or more delivery heads in order to simultaneously irradiate the patient 32 from two or more directions. The IMRT dose optimization 20 can employ any suitable optimization routine, and in some embodiments employs commercially available IMRT optimization products such as the Pinnacle3 Treatment Planning tool available from Koninklijke Philips N. V., Eindhoven, Netherlands. In some embodiments, the IMRT dose optimization 20 may adjust the control points (CPs) 22 to better achieve the set of radiation dose objectives 24; in other embodiments the control points (CPs) 22 are fixed during the IMRT dose optimization 20. It should also be noted that the term “optimization” and similar phraseology does not necessarily connote that the absolute best solution is achieved; rather, the optimization is sufficient to achieve the set of radiation dose objectives 24 within specified tolerances.
The output of the radiation therapy plan 40 comprising radiation delivery settings 44 at the sequence of plan control points (CPs) 22. Each control point (CP) 22 is defined by a configuration of the components 30, 32, 36. At a minimum, the components of the configuration include at least the radiation delivery device 30 and the patient 32. The configuration of components defines the positions of the components in a common coordinate system. In addition to the control points (CPs} 22, a plurality of configurations between control points of the sequence of control points (CPs) 22 are traversed during execution of the radiation therapy delivery plan, e.g. during rotation of a gantry of the radiation delivery device 30 from one control point (CP) 22 to the next, and (in techniques such as 4 pi radiation delivery) possible concomitant movement of the patient 32. The radiation therapy plan 40 is suitably executed by the radiation delivery device 30 applying radiation to the patient 32 using the beam-on time, MLC settings, trajectories defined by the CPs 22, and other parameters of the radiation therapy plan 40. The radiation therapy plan 40 may employ a 4 pi delivery mode, stepwise delivery with radiation being delivered only at the successive CPs 22, or a continuous arc therapy mode such as Volumetric Arc Therapy (VMAT).
Usually, prior to a generation of the radiation therapy plan 40 (and, of course, therefore prior to actual delivery of the radiation therapy), a simulation stage is done for most cancer patients in which they are imaged usually with computed tomography (CT) imaging, although magnetic resonance (MR) scanning may be used for the planning imaging. The CT (or MR) imaging to produce one or more CT (or MR) planning images 46, and a simulator 48 simulates the intended radiation therapy session to define the geometry, identify areas of the body to be exposed to ionizing radiation and areas to be blocked or shielded from radiation, prior to dose optimization and the actual treatment. The simulator 48 provides information on the patient's anatomy in the treatment position and localizes the patient's position during treatment. In some embodiments disclosed herein, this simulation stage incorporates collision detection as disclosed herein, run with a simulated in-room delivery at the time of simulation, to give the simulation therapist a sense of whether the patient's physical setup will be usable at the time the delivery happens or when the radiation therapy plan is performed. In this approach, the collision detection disclosed herein is used well before the planning stage (or control points) are executed. The therapist can thereby use feedback from the simulation to adjust the patient's position to mitigate any potential collisions later on.
With continuing reference to
However the surface models 30m, 32m, 36m of the respective physical components 30, 32, 36 are generated, these models are imported or input to the ray tracing system. Optionally, surface portions of the modeled components 30, 32, 36 which may not be included in the imported surface models may be generated by estimated extensions, e.g. of arms/legs/devices that are not in the CT or other scan employed in generating the imported model. A graphical user interface (GUI), computer aided design (CAD) drawing, or other available information may additionally or alternatively be leveraged in generating (or extending) the surface models 30m, 32m, 36m. The component modeling is also preferably extensible in order to add surface models for representing patient fixation devices or other patient-specific devices as models and allow users to drag and drop them into the configuration.
For a given configuration (which could be a CP, or could be a configuration along a possible trajectory being simulated during the initial simulation phase 48), the various components 30, 32, 36 are represented by their respective 3D models 30m, 32m, 36m positioned in a common coordinate system. (Note that
e.g. three pairs in the case of three components, six pairs in the case of four components, ten pairs in the case of five objects, and so on.
The foregoing ray tracing proximity analysis performed for each configuration generates a configurations matrix 52 storing, for each processed configuration, the proximity between each pair of components as a function of time, CP, or other metric. In some embodiments, the configurations matrix 52 includes only the configurations of the plan CPs 22 of the radiation therapy delivery plan 40 and the configurations traversed in moving between those CPs 22. In other embodiments, the ray tracing proximity analyzer 50 is applied to compute the proximity of each pair of components for all credible configurations that could be employed that is to say, for all possible (credible) combinations, so that they are available for the initial simulation phase as the simulation therapist explores possible delivery trajectory options using the therapy session simulator 48. In this case, all the processed configurations can also later be fed to the radiation therapy planning device 20 for use in trajectory tuning or optimization including identifying any collisions at the particular CPs of the sequence of plan CPs 22 and the intervening configurations traversed when moving between CPs. In either approach, the configurations are preferably computed for a chosen resolution of movement when traversing between configurations. For example, the resolution may employ (as a non-limiting example) five degree rotation increments of the radiation delivery gantry and three degree rotational increments for the patient support 34.
To perform collision detection, the configurations matrix 52 is input to a modeling-based collision detector 58 which models the configurations using the 3D models 30m, 32m, 36m and detects whether any of the proximity values indicate a collision. While strictly speaking a “collision” would ordinarily imply the two components making up the pair of components actually contact each other (so that the shortest ray would be zero or negative), in practice it is generally preferable to define a margin (e.g. stored in a margins table 56) for each pair of components, and to define a collision as the proximity (shortest ray) being less than the chosen margin for the pair of components. The margins 56 may be chosen to ensure safety by making the margin for a pair of components larger than the statistical uncertainty in position of the components. In some cases, the margin may be chosen to be larger than this. For example, although the statistical uncertainty of the radiation delivery head 38 may be small, the margin for the pair consisting of the radiation delivery head 38 and the patient 32 may be chosen to be larger than the statistical uncertainty due to the likelihood that a close pass of the delivery head 38 to the patient's body will be discomforting for the patient. Thus, in general, a collision is identified in a configuration as any pair of components whose proximity (shortest ray in the ray tracing) is less than the margin (e.g. stored in the margins table 56) for the pair of components.
Thus, in one illustrative embodiment, therapy session simulator 48 is invoked by the simulation therapist, treatment planner, or other medical professional, which allows for exploration of various possible therapy delivery implementations. If an explored implementation would traverse a configuration indicated by the modeling-based collision detector 58 as having a collision, then an editor or other graphical user interface 62 of the modeling-based collision detector 58 illustrates the collision using a 3D rendering of the 3D surface models 30m, 32m, 36m positioned in the common coordinate system in accordance with the configuration containing the collision. The user may then choose to adjust the explored trajectory (or the control point if a sequence of control points for a specific therapy plan is being set up) in order to eliminate the collision. Once the user settles on the geometry and exposure regions for the radiation therapy, the sequence of plan CPs 22 is calculated and/or optimized 20 into a set of control points.
In some embodiments, during the IMRT dose optimization 20 the plan CPs 22 are treated as plan parameters which are optimized along with other plan parameters (MLC settings, et cetera), and if a thereby adjusted CP is indicated as having a collision, the CP containing the collision is adjusted automatically, without user intervention.
In a variant embodiment, the configuration matrix 52 does not include any configurations having collisions, and so the IMRT dose optimization 20 cannot select any sequence of CP with collisions.
With continuing reference to
With reference to
With reference back to
To illustrate a collision, the 3D component models 30m, 32m, 36m are suitably rendered on the display 12 in their positions in the common coordinate system for the configuration containing the collision. Optionally, the collision point is highlighted or flagged on the display. Optionally, the user may select to move one or both of the colliding components by clicking on and moving the corresponding 3D surface model so as to adjust the configuration to avoid the collision. After adjusting the configuration, the collision detection may be repeated to determine whether the adjustment was sufficient to eliminate the collision. In an alternative remedial action, the user might elect to decrease the margin for the two colliding components to a smaller value so as to permit the simulated proximity. In other embodiments, it is contemplated to employ a less detailed output for displaying identified collisions. For example, the display 12 could list the configurations containing identified collisions and the pair of components in each such configuration that are identified as colliding, without providing a 3D rendering of the identified collisions.
With reference to
With continuing reference to
With continuing reference to
As is known in the art, the radiation therapy may be performed using a fractionated delivery, in which the patient returns for successive radiation therapy sessions over which the full radiation dose is delivered. In such a case, it is contemplated for various portions of the workflow of
In the disclosed approach, ray tracing is used in conjunction with realistic 3D surface models of the components in order to identify collisions, in the pre-planning simulation phase 48 and/or during the Radiation Treatment planning 20. This approach advantageously accounts for the detailed surfaces of the components and their spatial relationships. However, other collision detection techniques besides ray tracing may be used, such as by adding dilation to each 3D surface model and detecting a collision as an overlap at the voxel level between two dilated surface models. For example, if the surface of the patient 3D surface model 32 and the conebeam CT surface model 36 are each dilated by 10 cm, then a collision between the camera and the patient is detected as voxel overlap if the CT comes within 20 cm of the patient.
The disclosed collision detection approaches can be used in a variety of ways such as: 1) a quality assurance check to determine if arc, 4Pi, or static therapy is truly deliverable prior to physically attempting the delivery including all available 3D models of in-room devices, 2) to determine allowed beam angle positions prior to creating the treatment plan for/during IMRT or manual planning, 3) to determine and incorporate safety margins for collisions into the treatment plan, 4) to provide a matrix of possible collisions as input into the dose optimization algorithm 20, 5) to calculate and display trajectories such that the desired treatment plan is deliverable between planned CPs, 6) for reduction of patient dose due to scatter off accessories or beam source widening, or so forth, 7) for estimation of potential collisions prior to treatment plan creation during the CT (or MRI or other) simulation so that it can be known during this stage whether the patient needs to be re-imaged (re-simulated, re-situated) in a different position to avoid potential collisions detected during the treatment planning and delivery process, and/or 8) to provide an interface to import and model the 3D representation and position of all desired devices in the treatment room.
The invention has been described with reference to the preferred embodiments. Modifications and alterations may occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
This application is the U.S. National Phase application under 35 U.S.C. § 371 of International Application No. PCT/EP2017/083656, filed on Dec. 19, 2017, which claims the benefit of U.S. Provisional Patent Application No. 62/438,504, filed on Dec. 23, 2016. These applications are hereby incorporated by reference herein.
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PCT/EP2017/083656 | 12/19/2017 | WO |
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WO2018/115022 | 6/28/2018 | WO | A |
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