System and method for patient positioning during radiotherapy

Abstract

A system and method for patient positioning during radiation therapy. The system can include a patient support structure configured to receive a patient during a radiation therapy process using a radiation source to deliver therapy to the patient while the patient is positioned on the patient support structure; a patient positioning system configured to adjust a body position of the patient support structure relative to the radiation source, a flexible actuator configured to secure the patient to the patient support and adjust a body position of the patient relative to the patient support, and an imaging system configured to acquire imaging data of the patient, the patient support, and the flexible actuator during the radiation therapy process.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Patent Application No. 62 / 942,418, filed on December 2, 2019, entitled “Robot Systems for Compact Proton Therapy System,” which is incorporated herein by reference in its entirety.

[0003] A Note About Federally Funded Research

[0004] not applicable. Background Art

[0005] Radiation therapy is a form of tumor treatment that uses radiation to damage the deoxyribonucleic acid ("DNA") of tumor cells, either directly or indirectly (e.g., through oxygen free radicals), thereby destroying the tumor cells or inhibiting their ability to reproduce. Radiation therapy includes the use of photons (e.g., X-rays) to deliver radiation, and the use of particles (e.g., protons, electrons, etc.) to deliver radiation. In general, particle radiation therapy is considered the most advanced and precise form of radiation therapy. For example, in proton radiation therapy, a proton beam that travels through matter deposits most of its energy before it stops, which is characterized by a peak in the curve of the energy loss of ionizing radiation traveling through matter, which is called the Bragg peak. Therefore, compared to conventional photon radiation therapy, particle radiation therapy can reduce the radiation dose to healthy tissue (e.g., reduce side effects) while increasing the radiation dose to tumor tissue.

[0006] Despite the considerable advantages of particle radiation therapy, less than 1% of patients currently receiving radiation therapy receive proton therapy. Some of this disparity can be attributed to the high capital costs and the large footprint required for treatment systems. For example, the typical size of a state-of-the-art proton therapy system is around 200 m 2 to 600m 2 The system is approximately 12 meters tall, a size much larger than other more traditional photon-based radiotherapy systems. As the size and cost of these proton radiotherapy systems (and other particle-based systems) decrease, particle-based radiotherapy can be provided to more patients.

[0007] Further, implanting a suitable or ideal particle radiation therapy plan is complex and requires a significant amount of manual resources. For example, particle radiation therapy systems utilize a fixed source about which the patient must be precisely positioned. That is, correctly utilizing the Bragg peak requires very precise positioning of the patient to ensure that the charged particles reach the tumor at the point at which the particle experiences the Bragg peak. This requires careful planning, but then requires a significant amount of manual manipulation to ensure that the patient is properly positioned.

[0008] The relative lack of precision required for photon radiation therapy allows for the use of a radiation source that can be moved about the patient, and even the use of a patient bed that can be moved and adjusted. That is, photon radiation therapy does not employ the Bragg peak necessary to precisely deliver individual particles to the tumor. Given the relative lack of precision required, and to limit undesirable radiation to healthy tissue, systems have been developed that can move the radiation source about the patient, and even adjust the patient bed position relative to the radiation source to allow for the delivery of the beam at a variety of different angles during photon radiation therapy. By moving the beam position relative to the patient, the dose of radiation received by healthy tissue aligned along one delivery position of the photon radiation beam can be reduced.

[0009] Unfortunately, in particle radiation therapy, patient movement, even slight movement, can be particularly problematic because patient movement can cause the particles to experience the Bragg peak at an inappropriate or undesirable location. As a result, patients are typically positioned on a fixed bed and secured using straps so as to fix the patient in a fixed position throughout the radiation therapy. While the strategic use of the Bragg peak helps to control damage to healthy tissue, it does not improve such damage.

[0010] Regardless of whether the radiation therapy is particle-based or photon-based, improvements in systems and methods are desired to control undesirable radiation doses and to ensure careful implementation of the radiation therapy plan. SUMMARY

[0011] The present disclosure overcomes the aforementioned shortcomings by providing systems and methods for patient positioning, patient fixation, and patient repositioning during a radiation therapy procedure. Some aspects of the present disclosure provide systems and methods for delivering radiation therapy to a patient that can be computer-controlled and automated to ensure proper patient fixation and patient repositioning even if the patient repositions during the radiation therapy procedure (even when the radiation therapy is particle radiation therapy) using an adjustable or controllable patient support system.

[0012] According to one aspect of the present disclosure, a system for delivering radiotherapy to a patient is provided. The system includes a patient support structure configured to receive a patient during radiotherapy using a radiotherapy source to deliver treatment to the patient while the patient is positioned on the patient support structure. The system also includes a patient positioning system configured to adjust a position of the patient support structure relative to the radiotherapy source, and a flexible actuator configured to secure the patient to the patient support and adjust a position of at least a portion of the patient relative to the patient support. The system further includes an imaging system configured to acquire imaging data of the patient, the patient support, and the flexible actuator during the radiotherapy, and a computer system. The computer system is configured to control the adjustment of the flexible actuator in at least one dimension, and receive the imaging data, and direct the patient positioning system to adjust the position of the patient support structure during the radiotherapy, and direct the flexible actuator to secure the patient and reposition at least the portion of the patient relative to a radiotherapy plan while the patient positioning system adjusts the position of the patient.

[0013] According to another aspect of the present disclosure, a system for delivering radiotherapy to a patient is provided, the system including a radiotherapy source configured to deliver radiotherapy to a patient during radiotherapy using a fixed beam. The system also includes a patient support structure configured to receive a patient during the radiotherapy, a patient positioning system configured to adjust a position of the patient support structure relative to the radiotherapy source, and a flexible actuator configured to secure the patient to the patient support and adjust a position of at least a portion of the patient relative to the patient support. The system further includes an imaging system configured to acquire imaging data of the patient, the patient support, and the flexible actuator during the radiotherapy, and a computer system. The computer system is configured to control the adjustment of the flexible actuator in at least one dimension, and receive the imaging data, and direct the patient positioning system to adjust the position of the patient support structure during the radiotherapy, and direct the flexible actuator to secure the patient and reposition at least the portion of the patient relative to a radiotherapy plan while the patient positioning system adjusts the position of the patient.

[0014] According to yet another aspect of the present disclosure, a method for constraining and repositioning a patient during radiotherapy is provided. The method includes determining a current position of a patient on a patient support, wherein the patient is positioned to receive radiotherapy from a radiotherapy source during a radiotherapy procedure that follows a radiotherapy plan, the radiotherapy plan including a relative position of the patient with respect to the radiotherapy source. The method also includes repositioning the patient during the radiotherapy procedure using a patient positioning system configured to adjust a position of the patient support structure with respect to the radiotherapy source, and including controlling a flexible actuator to secure the patient to the patient support, and using the flexible actuator to adjust a position of the patient with respect to the patient support to adjust at least a portion of the patient in at least one dimension. The method further includes acquiring imaging data of the patient, the patient support, and the flexible actuator during the radiotherapy procedure. The method also includes analyzing the imaging data in relation to the radiotherapy plan to determine an updated position of the patient with respect to the radiotherapy plan, and repositioning the patient using the flexible actuator to match a further updated position of the patient to the radiotherapy plan.

[0015] The above and other aspects and advantages of the present disclosure will become more apparent by describing in the following description, taken in conjunction with the accompanying drawings. In the description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration one or more example versions. The versions do not necessarily represent the full scope of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0016] The following drawings are intended to aid in understanding various features of the non-limiting examples of the present disclosure, and are not intended to limit the scope of the present disclosure or to preclude alternate implementations.

[0017] Figure 1 is a block diagram providing a schematic illustration of a radiotherapy system according to the present disclosure.

[0018] Figure 2 is a perspective view of one non-limiting example of a radiotherapy system according to the present disclosure.

[0019] Figure 3 is an isometric view of a patient positioned in a system including a patient support structure, and Figure 2 a patient control system and positioning system of the system of

[0020] Figure 4A is a cross-sectional view of a flexible actuator of the present disclosure adjusting between a partially deployed position and a contracted position.

[0021] Figure 4B is a cross-sectional view of a flexible actuator of the present disclosure deployed relative to a patient.

[0022] Figure 5 is an isometric view of one non-limiting example of a stent of a flexible actuator of the present disclosure.

[0023] Figure 6 is Figure 5 a top view of a support of a flexible actuator.

[0024] Figure 7 is a flowchart setting out a series of non-limiting example steps of a process of forming a patient restraint and repositioning during a radiotherapy treatment according to the present disclosure.

[0025] Figure 8 is a photograph of a non-limiting example of a flexible actuator used in one non-limiting experimental design according to the present disclosure.

[0026] Figure 9 is a modified photograph of an experimental setup of a flexible actuator designed to be used as a shoulder fixation and repositioning unit attached to 2kN load cells for testing according to one non-limiting experimental design of the present disclosure.

[0027] Figure 10 is a graph of the holding force achievable at different levels of vacuum pressure according to one non-limiting experimental design of the present disclosure.

[0028] Figure 11A is a photograph of a volunteer sitting in a vertical patient chair having a non-limiting example of a flexible actuator controlled and monitored by a system relative to a region of interest (ROI) for right chest supine body position monitoring according to the present disclosure while performing a non-limiting experimental design.

[0029] Figure 11B is a photograph of a volunteer seated in a patient positioning system according to the present disclosure and in a tilted body position of 8.6° in the rolling direction, wherein the flexible actuator is engaged with a shoulder region monitored by markers attached to a chest region while performing a non-limiting experimental design.

[0030] Figure 12A is a photograph of a volunteer with markers (asterisks) attached seated on a patient positioning system while performing a non-limiting experimental design.

[0031] Figure 12B is a photograph of a volunteer moving the body upwards. Figure 12A

[0032] Figure 12C is a photograph of a volunteer showing the system according to the present disclosure correcting the volunteer's movement. Figure 12B

[0033] Figure 13 ​​are a series of plots from a non-limiting experimental study evaluating a flexible actuator on a volunteer. The curves correspond to measurements without and with the soft robotic fixation and positioning device. The black horizontal lines on each plot are the clinical positioning accuracy requirements of 1 mm and 0.5°. The breathing pattern can be seen as a high frequency variation.

[0034] Figure 14 are a series of plots from a non-limiting experimental study evaluating a flexible actuator on a set of volunteers. The data is filtered with a Savitsky-Golay filter. Lines of the same color represent the same volunteer without (dashed line) and with (solid line) the soft fixation and positioning device.

[0035] Figure 15 are a series of plots from a non-limiting experimental study evaluating a flexible actuator on two volunteers in an 8.6° tilted body position. The data is filtered with a Savitsky-Golay filter. Lines of the same color represent the same volunteer without (dashed line) and with (solid line) the soft fixation and positioning device.

[0036] Figure 16 are a pair of plots from a non-limiting experimental study investigating 3 degrees of freedom body position changes of a volunteer (lower plot) and with the motion correction experiment (upper plot). For the upper plot, the marker is moved by 45 mm after 0.25 seconds and the body position is corrected within ±1 mm in 2 seconds. For the lower plot, the marker is moved after 0.5 seconds and the body position is corrected within 1 mm in 4.5 seconds. DETAILED DESCRIPTION

[0037] Radiation therapy (radiotherapy) including both photon radiation therapy and particle radiation therapy is an indispensable tool in modern medicine. However, as described above, the effectiveness of these tools can vary based on the extent to which a clinician can manage the limitations and constraints of each system.

[0038] In addition to the practical challenges of effectively implementing a particle radiation therapy plan, it is important to note that the accessibility of proton-based radiation therapy is limited for a large number of patients, even if such patients can benefit from proton-based radiation therapy. To increase the accessibility of proton therapy, it is necessary to reduce the cost or size of proton therapy systems. In terms of size, one solution aims to fit a proton therapy system into a regular radiation therapy room with an area of about 50 m 2 Establishing such a compact proton therapy system that fits in a regular treatment room would enable more hospitals to offer proton therapy to patients. However, reducing a proton therapy system from 200 m 2 (Height = 12 m) to 50 m2 (Height = 3m) is challenging due to the nature of the particle beam (e.g., Bragg peak) and the need to position the target of the radiation relative to the particle beam and maintain a high degree of positioning accuracy, typically within 1 mm and 0.5° at the target site (e.g., tumor). This is especially difficult given the relatively small footprint of the space, which must be fitted into components including a proton accelerator, a proton beamline and scanning nozzle, a positioning and immobilization system, an imaging system (X-ray, magnetic resonance imaging ("MRI"), surface imaging, optical imaging (e.g., using a camera), etc. can be selected).

[0039] One approach to reducing the footprint and cost of a particle therapy system is to remove the conventional gantry. For example, rather than using a 100-ton proton gantry to bend the beam around the patient to allow for slightly different directions of incidence of the beam, treatment can be performed using a horizontal fixed proton beamline rather than a moving source, with the patient moved or adjusted relative to the fixed beam. While the removal of the gantry frees up considerable space, the removal of the gantry also requires more attention to the positioning and immobilization of the patient. For example, because the patient can move to different body positions (e.g., according to a radiation treatment plan) with a gantry-less system (e.g., fixed beam), it is critical that the target(s) in the patient be properly positioned and immobilized relative to the radiation source regardless of the body position. For example, the patient needs to be reliably immobilized and moved to different body positions with a high degree of accuracy, including, for example, a sitting body position, a reclining body position, and a lying body position.

[0040] Some conventional methods for immobilization generally cannot be translated for radiotherapy and thus do not address this issue. For example, seat belts on cars and other vehicles can immobilize a patient to a seat, but the patient can still shift or move relative to the seat. Thus, seat belts cannot provide sufficient immobilization for radiotherapy. Other conventional methods, including thermoplastic shells and vacuum bags, are generally used during patient supine position. For example, during supine position, a patient can be immobilized using a personalized thermoplastic shell, a modified Gill-Thomas-Cosman frame for brain treatment, or a vacuum bag for immobilization. While these devices can properly immobilize a patient while the patient is lying down, these devices are insufficient and are not substantially translatable for other patient positions (e.g., sitting or reclining positions) or when moving between different positions. For example, these devices do not have sufficient flexibility to accommodate other positions other than lying down. In fact, thermoplastic shells and vacuum bags are personalized molds made for a single treatment position for each patient. Thus, because many radiotherapy plans, especially those implemented using fixed beam radiotherapy systems, require a patient to be in multiple different orientations, multiple such devices are necessary, one for each different position. For example, multiple thermoplastic shells and vacuum bags need to be made and stored for each different position. This configuration has drawbacks. First, on each day of treatment, the patient needs to be repositioned by changing to a different set of immobilization devices, which adds additional time and complexity issues (e.g., prone to errors). Second, if there is a change in the patient’s body type during treatment (ranging from 1 day to 35 days), the conventional immobilization devices can need to be re-molded to the new body type.

[0041] Some non-limiting examples of the present disclosure provide advantages for these issues (and others) by providing improved systems and methods for patient positioning during radiotherapy. For example, some non-limiting examples of the present disclosure provide a patient support structure to support a patient, a system to adjust the patient support structure, and a system that can immobilize a patient to the patient support and reposition the patient after a movement (whether caused by the patient or by movement of the patient support structure). The system can include a plurality of flexible actuators that can be actuated in at least two actuation directions (or in at least one actuation direction in some cases), and each flexible actuator fixes a portion of the patient by coupling opposite portions (e.g., ends) of each flexible actuator to the support structure. Each of these flexible actuators can immobilize a different portion of the patient to the patient support structure. For example, a first flexible actuator can support one shoulder of the patient, a second flexible actuator can support an opposite shoulder of the patient, and a third flexible actuator can support a waist (or groin) of the patient. A fluid source can be in communication with the interior volume of the flexible actuators to drive actuation of the flexible actuators.

[0042] In some non-limiting examples, increasing the actuation force provided to a given flexible actuator provides at least three advantages. First, the increase in actuation force itself pulls the portion more tightly against the patient support structure. Second, the increase in actuation force provides a tactile response to the patient, which improves the patient’s attention, which can help the patient to pull the desired muscle to maintain the body position. Thus, the flexible actuator can help prevent the patient from slacking due to gravity pulling and relaxing (e.g., due to lack of attention). Third, the multidirectional movement of the flexible actuator can be used to reposition the patient, as well as, in some cases, a target within the patient relative to other organs.

[0043] Figure 1 is a schematic diagram of a radiation therapy system 100 according to the present disclosure. The radiation therapy system 100 can include a radiotherapy system 102 having a radiation source 104, an imaging system 106, a patient positioning system 108 having a patient support structure 110, a patient control system 112 having a flexible actuator 114, a flexible actuator 116, a flexible actuator 118, and a computer system 120. The radiotherapy system 102 can be implemented in different ways. For example, the radiotherapy system 102 can include a rotatable gantry that is rotatable about one or more rotational axes, which is implemented as a cylindrical gantry, a ring gantry, a C-arm gantry, etc. As another example, the radiotherapy system 102 can be implemented as including a robotic arm having the radiation source 104 coupled thereto. In this case, the robotic arm moves the radiation source 104 to different positions and orientations. As yet another example, the radiotherapy system 102 can be implemented as a gantry-less radiotherapy system, in which the radiation source 104 generates a fixed radiation beam (e.g., a proton beam). In this case, the gantry-less radiotherapy system can include other components, such as a particle accelerator (e.g., a cyclotron, a synchrotron, a linear accelerator (“LINAC”), etc.), a particle beam line nozzle (e.g., to emit a radiation particle beam), and radiation particle beam adjustment components to shape a trajectory of the radiation particle beam, which can include selectively activated magnets.

[0044] In some non-limiting examples, the radiation source 104 can be implemented in different ways depending on the particular implementation of the radiation therapy system 102. For example, the radiation source 104 can be a photon-based radiation beam former, such as an X-ray beam forming component configured to emit X-rays (e.g., an X-ray beam). In other cases, the radiation source 104 can be configured as a LINAC that emits a (charged) particle radiation beam (e.g., electrons, protons, etc.), such as, for example, when the radiation therapy system 102 is implemented as a robot arm including the radiation source 104 coupled thereto. In other cases, such as when the radiation therapy system 102 is implemented as a gantryless radiation therapy system, the radiation source 104 can include one or more charged particle accelerators (e.g., LINACs, cyclotrons, etc.) and can include beamline nozzles configured to direct a radiation particle beam (e.g., a proton radiation beam). In such cases, the radiation source 104 can include other beam direction and focusing components, such as radiation particle beam bending magnets and radiation particle beam focusing magnets. In some cases, these magnets can be electromagnets that can be selectively activated by the computer system 120.

[0045] In some non-limiting examples, the radiation therapy system 100 can include an imaging system 106 that can be configured to acquire imaging data of the patient, the patient support, and the patient control system 112 (including the flexible actuators 114, 116, 118). For example, when the patient is positioned and secured onto the patient support structure 110 by the flexible actuators 114, 116, 118, the imaging system 106 is configured to acquire imaging data including the patient, the patient support structure 110, and the patient control system 112 (including each of the flexible actuators 114, 116, 118). In some cases, the imaging data acquired by the imaging system 106 can be two-dimensional (“2D”) imaging data, or three-dimensional (“3D”) imaging data.

[0046] The imaging system 106 can be implemented in different ways. For example, the imaging system 106 can be implemented as a medical imaging system, such as an x-ray or fluoroscopy system. However, the imaging system 106 can be any of a variety of imaging modalities or combinations of imaging modalities, such as a computed tomography (“CT”) imaging system (e.g., a C-arm CT system), a magnetic resonance imaging (“MRI”) imaging system, a positron emission tomography (“PET”) imaging system, etc. In other cases, the imaging system 106 can be an optical-based imaging system, including one or more imaging sensors (e.g., charge-coupled device (“CCD”) imaging sensors, complementary metal-oxide-semiconductor (“CMOS”) imaging sensors, etc.). In particular, the imaging system 106 can include one camera or two cameras (e.g., in a stereoscopic configuration), etc. Regardless of the imaging modality, the imaging system 106 can use a plurality of imaging markers (e.g., imaging fiducials) that can be placed on a patient (such as, for example, on one or more of the flexible actuators 114, 116, 118) and used by the imaging system 106 to track the position of the markers relative to the portion of the subject to which the markers are coupled as appropriate. As shown, the computer system 120 is in communication with the imaging system 106.

[0047] The patient positioning system 108, including the patient support structure 110, can be implemented in different ways. For example, the patient support structure 110 can be a device similar to a chair that supports a patient when the patient is seated in a chair body position. In this case, for example, the chair can be one or more portions of the chair that are actuatable relative to other portions of the chair. For example, the backrest (or seat) can be pivotable relative to the seat (or backrest). In other cases, the chair is a rigid structure that is movable by the patient positioning system 108. In other cases, the patient support structure 110 can be a table that supports a patient when the patient is in a lying down position. In some cases, the patient positioning system 108 can move the patient support structure 110 in three or more degrees of freedom (e.g., six degrees of freedom). For example, the patient positioning system 108 can include a plurality of robotic links (e.g., arms coupled to actuators) that can collectively move the patient support structure 110 to different positions and orientations. In some cases, sensors (e.g., encoders) of the patient positioning system 108 can sense the collective body position of the support structure 110, which can be utilized by the computer system 120. As shown, the computer system 120 is in communication with the patient positioning system 108. Thus, the computer system 120 can sense the current body position (and orientation) of the patient support structure 110 and can associate that body position (and orientation) with the patient (e.g., register the coordinate system of the patient positioning system 108 with the coordinate system of the imaging system 106).

[0048] In some configurations, the computer system 120 can also cause the patient positioning system 108 to move the patient support structure 110 to different body positions (and orientations) as desired, such as according to a radiation treatment plan. For example, such as when the patient support structure 110 is a chair, the computer system 120 can cause the patient positioning system 108 to move the patient to different body positions, such as a sitting body position, a reclining body position (e.g., by partially actuating and thus pivoting a backrest portion of the chair relative to a seat of the chair), or a lying body position (e.g., by fully actuating and pivoting the backrest portion of the seat until the backrest portion of the seat is substantially coplanar with the seat (e.g., with less than ±10% deviation)).

[0049] In some configurations, the patient control system 112 secures the patient to the patient support structure 110 and can provide a dynamically adjustable securing force to particular portions of the patient. In this way and as will be described, the patient control system 112 enables both patient securing and patient positioning or repositioning. For example, each of the flexible actuators 114, 116, 118 can secure different portions of the patient to the patient support structure 110. Specifically, opposite ends of each of the flexible actuators 114, 116, 118 can be secured to the patient support structure 110, with at least a portion (e.g., a body) of each of the flexible actuators 114, 116, 118 enclosing a corresponding portion of the patient. In some cases, the flexible actuator 114 can secure a first body portion (e.g., a shoulder), the flexible actuator 116 can secure a second body portion (e.g., another shoulder) that is different from the first body portion, and the flexible actuator 118 can secure a third body portion (e.g., a waist) that is different from the first body portion or the second body portion. However, in other cases, some of the flexible actuators 114, 116, 118 can partially overlap one another or fully overlap one another (or substantially fully overlap). In this way, overlapping flexible actuators can provide a higher amount of securing for overlapping locations.

[0050] Each of the flexible actuators 114, 116, 118, when actuated, can be compressed in two dimensions (e.g., along the x-axis and the y-axis, within a plane, etc.) while being expanded in an opposite third dimension (e.g., along the z-axis, along a direction perpendicular to the plane, etc.). In some non-limiting examples, each of the flexible actuators 114, 116, 118 can be expanded in two dimensions while being contracted in the opposite third dimension when actuation is released. In this way, the forces provided by the flexible actuators 114, 116, 118 can be better distributed around the particular portion enclosed by the respective flexible actuators 114, 116, 118. In some cases, each of the flexible actuators 114, 116, 118 can include a sealed enclosure, a flexible and spine-like (e.g., bent along a curved line) scaffold within the sealed enclosure, a port in fluid communication with the sealed enclosure, a conduit coupled to the port and in fluid communication with the sealed enclosure, and a pump coupled to the conduit. The pump, when activated (e.g., by the computer system 120), can draw fluid (e.g., air) out of the sealed enclosure, thereby causing the respective flexible actuator to be actuated. The amount of fluid within a given flexible actuator is related to (e.g., proportional to) the pressure within the given flexible actuator. Thus, for each flexible actuator 114, 116, 118, a pressure sensor can be in fluid communication with the interior volume of the respective flexible actuator 114, 116, 118, each of which can be in communication with the computer system 120. Thus, the computer system 120 can determine the current actuation force of each flexible actuator 114, 116, 118 (e.g., to determine whether the computer system 120 should adjust the force of the flexible actuators). In some cases, the scaffold of each of the flexible actuators 114, 116, 118 can be perforated or can include holes to allow for better fluid communication between the layers. In some cases, the scaffold of each of the flexible actuators 114, 116, 118 can have a 2D folding pattern (e.g., a Miura folding pattern, a series of folds that extend within a plane) that can allow for contraction within the plane of the scaffold and expansion in the third dimension. In other cases, the scaffold of each of the flexible actuators 114, 116, 118 can have a 3D folding pattern (e.g., a series of folds that extend within a plane and within a remaining dimension perpendicular to the plane).

[0051] In some non-limiting examples, such as based on a current patient position according to a radiation therapy plan, computer system 120 can selectively adjust an actuation force of one or more of flexible actuators 114, 116, 118 (e.g., by removing fluid, or by allowing or forcing fluid to enter the flexible actuators via a pump). In this way, the patient can be more fixed (e.g., restricted) by the flexible actuators with the patient’s own additional force, while providing haptic feedback to the patient indicating that the patient refocus and flex certain muscles (e.g., muscles proximate to the flexible actuators). Additionally, in some cases, coordinating the actuation force of one or more flexible actuators 114, 116, 118 by computer system 120 can adjust the positioning of the patient or the position of a target within the patient relative to other organs, including internal positioning and restriction of organs. For example, when one flexible actuator is placed on a subject’s waist and a second flexible actuator is placed on the patient’s chest (or shoulder), the actuation of both flexible actuators can move organs (such as the liver) downward, and can fix the organs more in place than without the flexible actuators.

[0052] In some non-limiting examples, each of flexible actuators 114, 116, 118 can have a uniform thickness for a given compression force, which is desirable at least because if a radiation beam passes through a region of a flexible actuator, the radiation provided to that region is uniform. In other words, thus, the radiation delivered to a particular region from a radiation beam that passes through a flexible actuator of uniform thickness does not depend on the thickness of the flexible actuator.

[0053] Although patient control system 112 has been described as having three flexible actuators 114, 116, 118, fewer flexible actuators can be used, such as one or two, while in other cases, more flexible actuators can be used, such as four, five, six, etc. In some non-limiting examples, the dimensions of flexible actuators 114, 116, 118 can be determined in different ways, such as being as large as a blanket, or as small as a belt. In some cases, multiple flexible actuators can overlap according to a pattern (e.g., the bodies of the flexible actuators can overlap in a cross pattern). In certain cases, one or more of flexible actuators 114, 116, 118 (or others) can be integrated within a portion (or the entirety) of a garment, or configured to replace a garment, such as pants, a jacket, socks (or other footwear), a shirt, a suit (e.g., similar to a wetsuit), etc.

[0054] In some non-limiting examples, computer system 120 can be implemented in different ways. For example, computer system 120 can include typical components used, such as a processor, a memory, a display, input (e.g., a keyboard, a mouse, a graphical user interface, a touch screen display, etc.), a communication device, and the like. In some cases, computer system 120 can be implemented simply as a processor. Computer system 120 can communicate with other computing devices and systems. In some non-limiting examples, computer system 120 can implement some or all of the processes described below.

[0055] Figure 2 An example of a radiotherapy system 150 is shown as a specific implementation of radiotherapy system 100. For example, radiotherapy system 150 includes a radiation source 152, an imaging system 154, a patient support structure 156, a patient positioning system 158, a patient control system 160, and a computer system 162 in communication with radiation source 152, patient positioning system 158, and patient control system 160. Radiation source 152 is implemented as a beamline nozzle configured to emit a beam of radiation particles toward a patient, in this case a beam of protons. In this configuration, the beam of radiation particles (e.g., protons) is a fixed beam. In other words, the beamline nozzle that receives a beam of charged particles (e.g., protons) from a particle accelerator is fixed and does not move. In some cases, computer system 162 can adjust the trajectory of the beam of radiation particles by selectively activating magnets located within the beamline nozzle. Imaging system 154 is implemented as an X-ray imaging system, where an X-ray source 164 provides a beam of X-rays that passes through a patient and is detectable by an X-ray detector 166. Imaging system 154 is shown as a C-arm that is rotatable about one or more axes.

[0056] Figure 3An isometric view of a patient supported by the patient support structure 156 is shown, with the patient positioning system 158 engaged with the patient support structure 156 and the patient control system 160 installed. The patient support structure 156 is implemented as a chair having a backrest 168 coupled to a seat 170 and footrest 172. The backrest 168 is configured to support the back of the patient, the seat 170 is configured to support the hips of the patient, and the footrest 172 is configured to support the feet of the patient. Although the chair is shown as rigid, in other configurations, portions of the chair can be movable (e.g., actuatable to other portions of the chair). For example, the backrest 168 can recline backwards relative to the seat 170. The chair also includes arm supports 174, 176 each extending from a different side of the chair at an angle relative to the backrest 168. In some cases, the arm supports 174, 176 are coupled to opposite sides of the backrest 168. The arm supports 174, 176 are configured such that when the patient’s arms are placed on the respective armrests, the arms are elevated and lifted from the side of the patient. In some cases, such as in the non-limiting example shown, the chair can include support beams 178, 180 that provide mounting locations for the patient positioning system 158.

[0057] As shown, the patient positioning system 158 is implemented as a robotic system having three actuator components 182, 184, 186 that can be substantially similar to one another, so for the sake of brevity, only the actuator component 182 will be described. The actuator component 182 includes pivot links 188, 190 that are disposed at opposite ends of the support beam 178. Each of the pivot links 188, 190 can be rotationally urged by a respective motor (e.g., electric motor). In other words, each of the pivot links 188, 190 can be rotationally coupled to both an end of the support beam 178 and an assembly that rotates with the motor, thereby rotationally urging a given pivot link (e.g., by adjusting its position and orientation within a plane defined by the pivot link). This urging force forces the support beam 178 to adjust its orientation, thereby changing the orientation of the chair. As shown, the actuator component 184 includes pivot links that are rotationally coupled to the support beam 180, and the actuator component 186 includes pivot links (e.g., rails) that are rotationally coupled to the chair. Thus, the overall positioning of the actuator components 182, 184, 186 can adjust the position and orientation of the chair, thereby adjusting the position and orientation of the patient.

[0058] As shown, the patient control system 160 also includes three flexible actuators 192, 194, 196. The patient control system 160 is a specific implementation of the patient control system 112, and the flexible actuators 114, 116, 118 are specific implementations of the flexible actuators 192, 194, 196. Each of the flexible actuators 192, 194, 196 fixate a different portion of the patient. For example, the flexible actuator 192 has two opposite ends (or more ends, such as four opposite ends corresponding to each edge of the flexible actuator 194) that are coupled to the chair, and more specifically, to the backrest 168 of the chair, a first shoulder of the patient is enclosed by the flexible actuator 192. The flexible actuator 194 has at least two opposite ends that are coupled to the chair (e.g., the backrest 168 of the chair), a second opposite shoulder of the patient is enclosed by the flexible actuator 194. The flexible actuator 196 has at least two opposite ends that are coupled to the chair, a waist (or in some cases, a groin) of the patient is enclosed by the flexible actuator 196.

[0059] Each flexible actuator 192, 194, 196 can have a conduit in fluid communication with an interior volume of the respective flexible actuator, and can have a corresponding pump in fluid communication with the interior volume of the respective flexible actuator (e.g., via the conduit). Each pump can be controlled by the computer system 162 to pump fluid into the respective flexible actuator to stop the respective flexible actuator (e.g., to reduce the fixation force provided by the flexible actuator to the respective portion of the patient), or to pump fluid out of the respective flexible actuator to actuate the respective flexible actuator (e.g., to increase the fixation force provided by the flexible actuator to the respective portion of the patient). As shown, a conduit 198 is coupled at one end to the flexible actuator 196, and at an opposite end to a pump 199. The conduit 198 is in fluid communication with the interior volume of the flexible actuator 196. When the pump 199 is activated to draw fluid, fluid from the interior volume of the flexible actuator 196 is drawn out through the conduit 198 and through the pump 199 to increase the actuation force provided by the flexible actuator 196, or in other words, to further restrict the portion enclosed by the flexible actuator 196. When fluid is introduced back into the interior volume of the flexible actuator 196 (e.g., forcibly via the pump 199, or by reducing the suction of the pump 199), the actuation force provided by the flexible actuator 196 is reduced to reduce the restriction of the portion enclosed by the flexible actuator 196. The flexible actuators 192, 194 operate in a similar manner as the flexible actuator 196.

[0060] Figure 4A and Figure 4BVarious diagrams of a flexible actuator 200, which can be the flexible actuator described earlier, are shown. The flexible actuator 200 includes a sealed enclosure 202 that defines an interior volume 204, a stent 206 folded in at least a 2D folded pattern, connectors 208 connected to opposite ends of the sealed enclosure 202, connectors 210, and a port 212 in fluid communication with the interior volume 204. The stent 206 can have rigid portions defined between curved lines that can be folded and collapsed along each curved line. In some cases, the flexible actuator 200 can include perforations 214 directed through some (or each) of the rigid portions, or in other cases, the stent 206 can include a plurality of holes directed through some (or each) of the rigid portions. The holes and perforations 214 can provide fluid communication paths that can more easily drain or inject fluid from the interior volume 204.

[0061] The connectors 208, 210 are illustrated as straps or strips of material that extend from opposite ends of the flexible actuator 200. Each of the connectors 208, 210 can include one or more fasteners (e.g., hook-and-loop fasteners, threaded fasteners such as bolts, adhesives, etc.) to fasten a given connector to a patient support structure. As shown, the port 212 is in fluid communication with the interior volume 204 of the sealed enclosure. In some cases, the port 212 can provide an interface to more easily receive a catheter and couple the catheter to the flexible actuator 200.

[0062] Although the flexible actuator 200 has been illustrated as having a single port 212 and two connectors 208, 210, in other configurations, more ports can be added (e.g., with corresponding catheters to connect and fluidly communicate with various pumps or a single pump), and more connectors can be added, such as three, four, five, etc. In some cases, the sealed enclosure 202 is an elongated plate, in which case the connectors can extend from each side of the plate.

[0063] Referring to Figure 4A , the flexible actuator 200 is shown in a first configuration prior to actuation, and then is controlled to move to a second configuration (i.e., a collapsed or actuated configuration) after fluid is drained from the interior volume 204 to actuate the flexible actuator 200 (e.g., compressing the flexible actuator 200 in two dimensions present in a plane, while expanding the flexible actuator in a remaining dimension perpendicular to the plane). Figure 4BA flexible actuator 200 is shown secured on a patient support structure 215 having a ring 216, a ring 218. Specifically, a connector 208 is received by and secured to the ring 216 through the ring 216, and a connector 210 is received by and secured to the ring 218 through the ring 218. In this configuration, multi-dimensional actuation of the flexible actuator 200 delivers precisely controlled forces 219 to the patient, which can be used to secure and reposition the patient.

[0064] Figure 5 An isometric view of the stent 206 is shown. The stent 206 is folded in a 2D folding pattern, in which folds 220, 222, 224, 225 extend along an x-axis 226 and a y-axis 228 of the stent 206 (e.g., where the x-axis 226 and the y-axis are perpendicular to each other). In the non-limiting example shown, the folds 220, 222, 224, 225 are in a zig-zag shape, however in alternative configurations, the folds 220, 222, 224, 225 can have other shapes. Specifically, the 2D folding pattern is a Miura fold pattern, however in other configurations, other 2D folding patterns can be used. As shown, the stent 206 can include a plurality of holes 230 (e.g., as an alternative or in addition to the perforations 214) that are directed through the stent.

[0065] Reference is made to Figure 5 and to a top view of the stent 206 shown in Figure 6 When fluid is expelled from the interior volume 204, such as when the fluid is being used to treat a patient, the folds of the stent 206 can collapse along the x-axis 226 (e.g., by adjacent folds, such as folds 220, 222, connecting more closely) and the y-axis 228 (e.g., having folds along this direction folding on themselves). Additionally, as the stent 206 compresses, the stent 206 can also expand along the z-axis 232 (e.g., the z-axis is perpendicular to the x-axis 226 and the y-axis 228). Similarly, when fluid is introduced back into the interior volume 204, the stent 206 can expand (e.g., by unfolding) along the x-axis 226 and the y-axis 228, while the stent 206 can collapse along the z-axis 232.

[0066] Figure 7 A flowchart of a process 300 for restraining and repositioning a patient in a radiation therapy procedure that can be implemented using the radiation therapy system described above is shown. Portions or all of the blocks of the process 300 can be implemented using one or more computing devices (e.g., the computer system 120).

[0067] At 302, the process 300 can include a computing device receiving a radiation treatment plan for a patient. In some cases, this can include receiving a plurality of radiation beam paths, each having a desired depth, intensity, and duration. In some cases, each of the beam paths can define a corresponding different patient orientation (e.g., relative to a radiation source). In some cases, each beam path (or each patient position) in the radiation treatment plan can include a corresponding target location (e.g., internal target location) for the patient. For example, the target location can be a region of a tumor of the patient.

[0068] At 304, the process 300 can include the computing device moving, in accordance with the radiation treatment plan, the patient secured on a patient support of a patient positioning system to a next position. For example, the computing device can cause the patient positioning system to move the patient support (and thereby the patient) to a next desired patient position (and orientation). In some non-limiting examples, at 304, the process can include the computing device adjusting an actuation force of a flexible actuator of the securing system to secure, fix, constrain, or reposition the patient relative to the patient support (e.g., for a particular position in accordance with the radiation treatment plan).

[0069] At 306, the process 300 can include the computing device acquiring imaging data of the patient secured on the patient support of the patient positioning system (e.g., via an imaging system). In some cases, this can include the computing device determining, based on the imaging data, a current position of the patient on the patient support. This can be determined relative to a radiation source (e.g., a radiation particle beam). In addition to the position of the patient, this determines the location of the target (tumor) relative to surrounding healthy tissue and its shape.

[0070] At 308, the process 300 can include the computing device determining a difference (or lack thereof) between the current position of the patient and a desired position of the patient. In some cases, each of the current position and the desired position can be relative to a radiation particle beam, an imaging marker, an imaging fiducial, etc.

[0071] At 310, the process 300 can include the computing device determining whether the patient is within a movement tolerance (e.g., 1 mm). If, at 310, the computing device determines that the patient is within the tolerance, the process 300 can continue to block 314 of the process 300 to cause the radiation source to emit a radiation beam in accordance with the radiation treatment plan for that radiation beam path and corresponding patient position. Once the radiation treatment beam is provided in accordance with the radiation treatment plan, the process 300 can return to block 304 of the process 300 to move the patient to a next position (e.g., if there are additional positions) in accordance with the radiation treatment plan.

[0072] If, at 310, the computing device determines that the patient movement exceeds the threshold, the process 300 can continue to block 312. At 312, the process 300 can include the computing device determining a type of error and, based on the error, repositioning the patient by adjusting actuation of one or more of the flexible actuators, moving one or more of the patient positioning system or the radiation beam (e.g., a beam of radiation particles). In some non-limiting examples, this can include the computing device determining, based on the imaging data, that the error is a surface error or a skin error and, based on the surface error, adjusting actuation of one or more of the flexible actuators until the surface error is mitigated to provide a surface correction. In some non-limiting examples, this can include the computing device determining, based on the imaging data, that the error is a posture error (e.g., sloth) and, based on the posture error, adjusting actuation of one or more of the flexible actuators (e.g., increasing the actuation force) until the posture of the patient is within an appropriate level to provide a body position correction. In some non-limiting examples, this can include the computing device determining, based on the imaging data, that the error is a beam error (or an error that can be fixed by adjusting the beam) and, based on the beam error, adjusting a shape and trajectory of the radiation beam (e.g., by selectively activating magnets when the radiation source provides a beam of radiation particles).

[0073] In some non-limiting examples, such as if, at 310, the computing device determines that the target position for a particular body position exceeds the threshold, the computing device can adjust an actuation force of one or more of the flexible actuators until a portion of the target position is aligned with the radiation source (e.g., a fixed radiation beam or a beam nozzle that emits a fixed radiation beam). In this way, the one or more flexible actuators can move the target position internally, which can be a portion of a tumor of an internal organ (e.g., by choreographed actuation of the plurality of flexible actuators).

[0074] In some cases, once the computing device determines that the required movement has been made, the process 300 can return to block 306 to acquire additional imaging data.

[0075] Examples

[0076] The following examples are included to further illustrate certain aspects of the disclosure, and are not intended to limit the scope of the disclosure in any way. The following examples are intended to be illustrative only and are not intended to limit the scope of the disclosure (and other aspects of the disclosure) in any way.

[0077] Proton therapy has significant physical advantages over conventional x-ray cancer radiation therapy. Proton therapy can reduce the radiation dose to healthy tissue, thereby reducing toxicity and side effects to the patient. However, the current high capital cost and required space make proton therapy a very limited resource. In current proton therapy, the patient is fixed on a table and a gantry is used to bend the proton beam for treatment. We suggest a change in model to precisely move the irradiation target inside the patient relative to a fixed or slightly adjustable proton beam, rather than a coarse movement relative to the patient. This requires a robotic device to move the patient and a robust and flexible patient control device to ensure that the patient's body position is accurate during position change. We introduce a solution for compact and affordable proton therapy using a parallel robot with real-time surface positioning feedback and a patient fixation control system made of soft robotic actuators. Fixation experiments on healthy volunteers show that our prototype device can position and fix healthy volunteers in a sitting position according to clinical standards and correct their slouching through a feedback loop. The soft robotic patient control device is robust, soft, comfortable, and adaptable to body types. The force that the patient control device can exert on the body using negative pneumatic pressure is characterized. This new patient control device and robotic positioning system has great potential to significantly reduce the cost of proton radiation cancer therapy.

[0078] Combining several advanced technologies in robotics and control technology provides a solution to this problem. In this research, we designed and fabricated a general-purpose device made of soft actuators to provide firm yet comfortable patient control. In contrast to passive, non-electric devices such as belts, this soft robotic device can be controlled, and the force it exerts can be automatically adjusted for different patients. Additionally, the actuators can be designed to fit the shape of specific body parts to optimize coverage, thereby providing adaptive force for patient control. We used a 6-DOF parallel robot-controlled chair and integrated it with surface imaging in a feedback loop to achieve high accuracy and maneuverability of the patient between different treatment positions. More specifically, we fabricated soft patient controls based on the concept of fluid-driven, origami-inspired artificial muscles (FOAM). We evaluated the effectiveness of the system through experiments on healthy volunteers. Our soft actuators, patient control devices reduced the amplitude of the volunteers' position change and the breathing motion of some volunteers. The effectiveness of the controller integrated with surface imaging on positioning accuracy was evaluated and confirmed.

[0079] This research was designed to build on advances in proton therapy systems, soft robotics, robotic chairs, and tracking and positioning. We highlight recent relevant work in each of these categories.

[0080] The Harvard Cyclotron Laboratory began treating patients with proton beams in 1973. For decades, proton therapy has utilized the double-scattering technique for delivery. The pencil beam scanning (PBS) technique, developed in recent years, provides 3D dose modulation and, therefore, the potential for highly sophisticated dose shaping, even with individual beams delivered using high-resolution PBS.

[0081] Robotic couches with 3 DOF or 6 DOF have become commercial products in radiotherapy where patients are positioned in a lying position. To achieve a tracking accuracy of 0.5 mm, a 6 DOF Stewart robotic motion correction research platform was developed. However, robotic couches with the ability of real-time tracking and transferring the patient to multiple orientations relative to the main beam trajectory have not been applied in clinical or compact proton therapy systems.

[0082] Tumor position tracking and positioning have been widely studied subjects. Previous studies developed a closed-loop dynamic controller to track tumor respiratory motion using a couch. An algorithm was used to predict the tumor centroid position, taking into account the delay in the system. This study used computer simulations to show a maximum tracking error of 1 mm with two commercial treatment couches. A recent study optimized the motion-compensated trajectory of a 6 DOF robotic patient couch using the L-BFGS algorithm. This method took into account the mechanical and patient treatment limitations and concluded that the steepest descent trajectory was the best solution.

[0083] In our study, the novel soft patient control was designed based on the fluid-driven, origami-inspired artificial muscle (FOAM) concept. This is an easy-to-fabricate and very cost-effective design. To focus on the development and evaluation of the soft patient control device, we used a standard 6 DOF parallel robot base with a simple controller in this study. In addition, a chair top was integrated with this soft patient control device to realize a body position control system required in the clinic.

[0084] The system developed in this study includes a parallel robot base, a patient chair with attached soft patient control device, and an optical motion tracking system. This system was developed to allow patient control of the patient while providing accurate positioning of the patient.

[0085] When developing a robotic patient positioner in combination with a soft patient control device for a compact proton therapy system, the following design considerations were taken into account: (1) The patient control device needs to be (a) thin, i.e. < 5 cm, to allow positioning close to the radiation beam nozzle, (b) all-patient and reusable, (c) comfortable for the patient, and (d) have a reproducible thickness at every point and at every treatment, or be placed outside the treatment beam path; (2) The part of the robotic system that can be located in the treatment beam trajectory needs to be made of materials that attenuate the beam as little as possible, such as carbon fiber composite; (3) The clinical standard for body position accuracy has to be lower than 1 mm and 0.5 compared to the reference position; (4) The system needs to be easy to use.

[0086] In this study, we focused on a prototype for breast cancer treatment. The shoulder and abdominal regions were chosen as the location of the patient control unit to provide access to the breast region while preventing lazy motion of the patient in the sitting position.

[0087] A new soft patient control method was developed that meets the requirements of the system. The device consists of several individual units for different parts of the patient's body. Each unit is a fluid-driven, origami-inspired artificial muscle (FOAM) Figure 4A with a Miura-ori fold Figure 4B actuated by negative relative air pressure. This type of actuator has good durability and does not degrade in performance over 30,000 cycles of use. The Miura-ori fold was chosen because it has the ability to contract in-plane, bend easily around objects (e.g. the shoulder) in the direction of contraction, and its robustness. Although it is commonly used for actuation, by fixing the ends of the actuator to the base frame, thus restricting lateral contraction, a force is applied perpendicular to the actuator. Each unit is made by folding a 0.18 mm thick polyester film in a Miura-ori pattern to form the skeleton of the actuator. Perforations are made on the plastic film with a laser cutter (Universal laser Systems, Inc.) and then folded by hand. In the next step, the skin of the actuator is prepared by attaching plastic air hose connectors. Then, the skeleton is sealed inside a coated sealed nylon fabric sheet by a pulse heat sealer (American International Electric, Co.). The unit is completed by sticking the connectors to the skin at both ends.

[0088] Reference Figure 8 A specific experimental design for the soft patient control unit was created using a perforated plastic film folded in a Miura-ori pattern and then sealed in an airtight skin with air hose connectors and connection straps at both ends. The upper figure shows the unit in ambient air, while the lower figure shows the contracted unit, which is predefined by the folding pattern of the plastic film.

[0089] Reference Figure 9 A load cell manufactured using Instron 5944 (Instron, USA) was used to test the flexible actuator as a patient control system. Custom-made wooden half-cylinder was used to simulate the body part being pressed down by the cell. For pressure monitoring, Arduino UNO with pressure sensor was used.

[0090] To characterize the individual soft patient control cell, the cell was first deflated to (-99 ± 1) kPa to determine the collapse ratio of the cell. The collapse ratio reached approximately 75%. In the subsequent experiment, the relationship between the holding force and the applied pressure was investigated. A model representing the human shoulder region was made of plywood (half-circle with a radius of (20.0 ± 0.1) cm) and attached to the load cell of an Instron 5944 (Instron, USA) universal testing machine. The patient control cell was connected to a vacuum pump with a regulator and air pressure sensor attached to it. The pressure was adjusted to change the pressure difference between the device pressure and the atmospheric pressure while monitoring the load cell.

[0091] For each of the 80 different pressure differences tested, the force registered by the load cell was as shown in the pressure graph in Figure 10 . At (99 ± 1) kPa, a maximum force of (150 ± 4) N was reached. There was a linear relationship between the pressure and the force, and there was a small hysteresis effect.

[0092] Reference Figure 11A , Figure 11B , Figure 12A , Figure 12B and Figure 12C The robotic patient positioner developed in this study uses a Gough-Stewart platform and a patient chair. A commercial Stewart platform designed for driving and flight simulation (DOF Reality, Corp.) was used as the base of the patient positioner. The six rotational actuators of the system work in pairs, connected to motor drivers, and each rotational actuator is controlled by a microcontroller (Arduino UNO, Italy).

[0093] For this study, the patient chair installed on top of the Stewart platform was designed specifically for breast cancer treatment. The chair has height-adjustable arm supports for lateral arm placement, which provide support under the arms and in the axillary region to prevent slacking. A plastic headrest is attached on top of the chair backrest. T-slotted aluminum rails are located at the hip and shoulder regions of the chair, respectively, to be used as height- and width-adjustable connection points for the patient control cells.

[0094] We developed a platform software plugin. It allowed MATLAB (MathWorks Inc., USA) scripts to control the platform. Data streams from the Vicon tracking system (Vicon Motion Systems, UK) were analyzed in the same script. The data streams were used as feedback for a proportional controller that was used to accurately control the body position of the platform. A calibration routine was written to automatically calibrate the system and convert the body position vector from the Vicon coordinate system to the robot coordinate system.

[0095] This set of experiments evaluated the effectiveness of the soft patient control unit by measuring the movement of selected regions of interest (ROIs) on the body of immobilized healthy volunteers. The first part of the experiment was conducted in the radiation therapy room at the Massachusetts General Hospital (MGH) (Boston, USA) where the patient control device was attached to a patient chair placed on top of a machine cabinet. The therapy room was equipped with AlignRT (UK VisionRT), an FDA-approved optical motion tracking system for radiation therapy that can evaluate changes in the body position of ROIs with sub-millimeter accuracy in 6 degrees of freedom. This system uses triangulation to provide 3D surface images of the volunteers. The AlignRT system includes an operator computer and three camera stations on the ceiling. Each of the camera stations contains two stereo cameras, a speckle projector, and a texture camera.

[0096] To compare the effectiveness of the system, a group of volunteers sat on the patient chair were positioned at the isocenter, which is the position where the AlignRT has the highest accuracy. This group consisted of one female and four male volunteers with heights between 160 cm and 195 cm and weights between 50 kg and 90 kg. Two measurements were taken for each volunteer, each for 15 minutes. One measurement used the patient control device and one measurement did not use the patient control device. A breast model made of foam and covered with white tape to improve the detection capabilities of the AlignRT was taped to the volunteer's chest. The volunteers were asked to wear tight clothing to ensure minimal movement between the clothing and the body. Reference images of the volunteer's body surface were taken, and ROIs were selected that were similar to the clinical procedure. During the duration of the measurements, the AlignRT recorded the body position changes of the ROIs in 6 degrees of freedom with frame rates between 5 Hz and 6 Hz.

[0097] Due to the limited space in the hospital treatment room for a 6-DOF robot, the second part of the experiment was performed in a room equipped with a Vicon tracking system. The robotic patient positioner was used to tilt the chair, resulting in a maximum angle of 8.6° in the roll direction for the volunteer. Then, experiments were performed for 15 minutes without the patient control device and with the patient control device turned on. The Vicon tracking system uses 10 infrared cameras with infrared spotlights to illuminate their field of view. The system is calibrated to track the body position to sub-millimeter accuracy in 3 dimensions for a single reflective marker and up to 6 dimensions for multiple reflective markers grouped as an object. The volunteer's chest wall area is outlined by four reflective markers, which are grouped to measure changes in all 6 degrees of freedom.

[0098] In this experiment, the ability of the robotic patient positioner to correct for body position changes was evaluated. First, the robot was tested without a human payload to evaluate the limitations of the controller rather than the hardware under load. Body position changes were simulated by attaching Vicon markers to the chair and activating the controller, which was set to keep the markers in place. The Vicon tracker system monitored the body position of the markers as the controller moved the patient chair to reposition the markers.

[0099] In the next test, a volunteer sat in the patient chair and attached Vicon markers to the chest area. The volunteer moved their body upward, and the motion of the markers was recorded.

[0100] Figure 13 The results of the fixation and repositioning evaluation for one of the five volunteers sitting in an upright chair position are shown. The blue and pink lines indicate the body position changes without the patient control device and with the patient control device, respectively. The first row shows the body position changes in the x, y, and z directions. The x, y, and z directions are in the lateral, anterior-posterior, and superior-inferior directions of the body, respectively. The second row shows the rotational changes in the pitch (Rx), roll (Ry), and yaw (Rz) directions. The horizontal black dashed lines in each plot indicate the clinically required body position accuracy of 1 mm and 0.5 The high-frequency changes shown, especially in the z direction, are due to the chest wall motion caused by the volunteer's breathing. For some volunteers, this breathing pattern is less pronounced with the soft patient control device.

[0101] We used Savitzky-Golay filtering on the monitoring data to obtain the long-term trend of the patient's body position. For better comparison, Figure 14Body position trends for five volunteers are shown. For all five volunteers, our soft patient control device showed that body position changes were expected to decrease within 15 minutes. Motion in the z-direction was more significant than in other directions. The z-direction is the direction in which sloshing occurs. Only two volunteers had body position changes within 1 mm in the z-direction during the 15-minute monitoring period. This result motivated us to develop a controller for the robotic positioner to further correct body position changes to meet clinical requirements. All immobilized volunteers met the 1 mm and 0.5° requirements in the y-direction and three rotational directions. For the x-direction, two volunteers did not meet the 1 mm requirement.

[0102] Results of the fixed and positioned evaluation of the sloshing body position with a 8.6° roll angle are shown in Figure 14 . The volunteer's motion in all translations and rotations without the patient control device exceeded the tolerances. The fixed motion in the x-direction and rotations around the y- and z-axes exceeded the 1 mm and 0.5° tolerances by a small amount. We can utilize the controller on the robotic patient positioner to correct this body position change.

[0103] In the first part of the experiment with the volunteer on the patient chair, the marker was moved upward by about 45 mm in 2 s, and the controller was corrected to 1 mm, as shown in Figure 15 . This shows that the controller can correct and maintain the body position of the marker in 3D at a speed of (22.5 mm / s) that is much faster than the sloshing motion detected during the evaluation of the patient control device at (0.05 mm / s).

[0104] Even with the volunteer sitting on the patient chair, the results show that the robotic patient positioner can correct a 45 mm body position change within 4.5 cross sections within the desired tolerance range of ±1 mm. This indicates that the slow drift identified as sloshing (with a maximum sloshing motion of 0.05 mms -1 ) in the V-A segment can be corrected by the controller at an average speed of 10 mms -1 . The experiment shows that a proportional controller is sufficient to accomplish this task.

[0105] In this study, we present a more compact and affordable proton therapy system by developing a new soft robotic system for patient immobilization and repositioning that can provide a universal, actively controlled, and adaptive system for patients. We describe the design and fabrication method of the soft patient control device. Experiments in this study compare the performance between the soft robotic patient control device and the immobilization device without fixation on healthy volunteers. These experiments show that this device greatly reduces the lazy motion of the volunteers. More experiments will be conducted to compare our soft patient control device with the thermo-plastic mask and simple strap-like harness that are currently used clinically. These experiments should also be conducted for different tumor sites to determine the best solution for each disease site. For example, dedicated soft patient control devices for the head and neck and thoracic regions will be designed and fabricated. In addition, real patient testing will be conducted on this device to evaluate whether the current soft robotic patient control device is suitable for patients who can be weaker than healthy volunteers. Based on future patient testing, different folding patterns and materials can need to be used to allow more patient comfort.

[0106] In this study, we also introduce the development of a robotic base and patient chair prototype that provides accurate positioning and system integration. The 6-DOF parallel robotic system and controller in this study is the basic system that provides the functionality for the preliminary evaluation of the newly developed soft robotic patient control device. More advanced robotic and control systems will be developed in the future to be integrated with the patient control device for the next stage of the prototype. For example, actuated slewing bearings that allow 360° yaw rotation and an adaptable backrest tilt mechanism are needed. This study also provides an opportunity for the future development of more complex controllers that correct for respiratory motion.

[0107] Although more experiments and prototype iterations are needed for the development of the final product, this study shows that soft robotics can be used for patient immobilization in the sitting and reclining positions to achieve the 1 mm and 0.5° clinical positioning tolerances required for a compact gantry-free proton therapy system.

[0108] The present disclosure has been described with one or more preferred non-limiting examples, and it should be understood that many equivalents, alternatives, variations, and modifications, other than those explicitly described, are possible and within the scope of the present invention.

[0109] It is to be understood that the application of the present disclosure is not limited to the details of construction and the arrangement of components described in the following description or illustrated in the drawings. The present disclosure is capable of other non-limiting implementations and is capable of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. As used herein, the use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled" and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings.

[0110] As used herein, unless otherwise limited or defined, discussion of a particular orientation is provided by way of example only, involving a particular non-limiting example or related illustration. For example, discussion of a "top," "front," or "back" feature generally is intended to describe only the orientation of such feature relative to a reference frame of a particular example or illustration. Accordingly, for example, a "top" feature can sometimes be disposed below a "bottom" feature (and so on) in some arrangements or non-limiting examples. Further, reference to a particular rotation or other movement (e.g., counterclockwise rotation) generally is intended only as a description of movement relative to a reference frame of a particular example.

[0111] In some non-limiting examples, aspects of the present disclosure, including computerized implementations of methods according to the present disclosure, can be implemented using standard programming or engineering techniques, to produce software, firmware, hardware, or any combination thereof, to control a processor device (e.g., a serial or parallel general or special purpose processor chip, single or multi-core chip, microprocessor, field programmable gate array, any various combination of control units, arithmetic logic units, and processor registers, etc.), a computer (e.g., a processor device operably coupled to a memory), or another electronically operated controller to implement aspects detailed herein. Accordingly, for example, non-limiting examples of the present disclosure can be implemented as a set of instructions tangibly embodied on a non-transitory computer-readable medium, such that the processor device can implement the instructions based on reading the instructions from the computer-readable medium. Some non-limiting examples of the present disclosure can include (or utilize) a control device, such as an automated device, a special or general purpose computer including various computer hardware, software, firmware, etc., consistent with the discussion below. As a specific example, a control device can include a processor, microcontroller, field programmable gate array, programmable logic controller, logic gates, etc., as well as other typical components known in the art for implementing appropriate functionality (e.g., memory, communication systems, power supplies, user interfaces, and other inputs, etc.).

[0112] As used herein, the term "article of manufacture" is intended to encompass a computer program accessible from any computer-readable device, carrier, or media (e.g., non-transitory signal). For example, computer-readable media can include but are not limited to magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips), optical disks (e.g., compact disk (CD), digital versatile disk (DVD)), smart cards, and flash memory devices (e.g., card, stick). Additionally it should be appreciated that a carrier wave can be employed to carry computer-readable electronic data such as those used in transmitting and receiving electronic mail or in accessing a network such as the Internet or a local area network (LAN). Those skilled in the art will recognize many modifications can be made to this configuration without departing from the scope or spirit of the claimed subject matter.

[0113] Certain operations of methods according to this disclosure, or certain operations of systems performing those methods, can be represented schematically in the drawings or otherwise discussed herein. Unless otherwise specified or limited, representation of particular operations in the drawings in a particular spatial order does not necessarily require those operations to be performed in that particular order corresponding to the particular spatial order. Accordingly, certain operations represented in the drawings or otherwise disclosed herein can be performed in a different order than the order explicitly illustrated or described, in a manner suitable for a particular non-limiting example of the present disclosure. Further, in some non-limiting examples, certain operations can be performed in parallel, including by dedicated parallel processing devices, or by separate computing devices configured to interact as part of a larger system.

[0114] As used herein in the context of computer-implemented, the terms "component," "system," "module," and the like are intended to encompass parts of, or all of, computer-related systems including hardware, software, a combination of hardware and software, or software in execution. For example, a component can be, but is not limited to, a process, an object, an executable, a thread of execution, a computer program, or a computer. By way of illustration, both an application running on a computer and the computer itself can be a component. One or more components (or systems, modules, etc.) can reside within a process or thread of execution, can be localized on one computer, can be distributed between two or more computers or other processor devices, or can be included within another component (or system, module, etc.).

[0115] In some implementations, the devices or systems disclosed herein can be utilized or installed using methods embodying the disclosed aspects. Accordingly, descriptions of specific features, capabilities, or intended purposes of the devices or systems herein are generally intended to inherently include disclosure of methods of using such features for the intended purposes, methods of implementing the capabilities, and methods of installing the disclosed (or other known) components to support the purposes or capabilities. Similarly, unless otherwise indicated or limited, any discussion herein of methods of manufacturing or using a particular device or system, including installing the device or system, is intended to inherently include disclosure of the methods as non-limiting examples of the disclosure, as used features and implemented capabilities of such devices or systems.

[0116] As used herein, unless otherwise defined or limited, the ordinal numbers used herein are generally based on the order of presentation of the particular components in the relevant portion of the disclosure for ease of reference. In this regard, references such as “first,” “second,” etc. generally only indicate the order in which the relevant components are introduced for discussion and generally do not indicate or require a particular spatial arrangement, function, or structural priority or order.

[0117] As used herein, unless otherwise defined or limited, directional terms are used for ease of reference to discuss particular figures or examples. For example, references to downward (or other) directions or top (or other) body positions can be used to discuss various aspects of particular examples or figures, but do not necessarily require similar orientations or geometries in all installations or configurations.

[0118] The present discussion is presented to enable a person skilled in the art to make and use non-limiting examples of the present disclosure. Various modifications to the illustrated examples will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other examples and applications without departing from the principles disclosed herein. Thus, the non-limiting examples of the present disclosure are not intended to be limited to the non-limiting examples illustrated, but are to be accorded the widest scope consistent with the principles and features disclosed herein and the following claims. The following detailed description reads with reference to the figures, in which like elements in different figures have like reference numerals. The figures depict selected examples and are not intended to be limiting of the scope of the disclosure. The person skilled in the art will recognize that the examples provided herein have many useful alternatives and fall within the scope of the disclosed scope.

[0119] Various features and advantages of the present disclosure are set forth in the following claims.

Claims

1. A system for delivering radiotherapy to a patient, the system comprising: a patient support structure configured to receive a patient during radiotherapy using a radiotherapy source to deliver therapy to the patient while the patient is positioned on the patient support structure; a patient positioning system configured to adjust a position of the patient support structure relative to the radiotherapy source; a flexible actuator configured to secure the patient to the patient support and adjust a position of at least a portion of the patient relative to the patient support, wherein the flexible actuator forms an artificial muscle that contracts in one direction; an imaging system configured to acquire imaging data of the patient, the patient support, and the flexible actuator during the radiotherapy; and a computer system configured to: control adjustment of the flexible actuator in at least one dimension; receive the imaging data and direct the patient positioning system to adjust a position of the patient support structure during the radiotherapy and direct the flexible actuator to secure the patient and reposition at least a portion of the patient relative to a radiotherapy plan while the patient positioning system adjusts the position of the patient support structure.

2. The system of claim 1, wherein, the radiotherapy plan includes a positioning of the patient relative to the radiotherapy source or adjustment of a particle beam to utilize a Bragg peak during the radiotherapy.

3. The system of claim 1, wherein, the computer system is configured to control adjustment of the flexible actuator in at least two dimensions, and further comprising a vacuum pump in fluid communication with the flexible actuator and in electrical communication with a controller to effect adjustment of the flexible actuator in the at least two dimensions.

4. The system of claim 1, wherein, the computer system is further configured to direct the controller to adjust the flexible actuator to counteract a force of gravity acting on the patient while the patient positioning system adjusts the position of the patient support structure relative to the radiotherapy source.

5. The system of claim 4, wherein, the computer system is further configured to direct the controller to adjust the flexible actuator to reposition the patient to correct for a force of gravity acting on the patient while the patient positioning system adjusts the position of the patient support structure relative to the radiotherapy source.

6. The system of claim 1, wherein, the radiotherapy source is configured to deliver radiotherapy to the patient during radiotherapy using a fixed beam, and wherein the patient positioning system is configured to adjust the position of the patient support structure relative to the radiotherapy source in 3 degrees of freedom, 4 degrees of freedom, 5 degrees of freedom, or 6 degrees of freedom.

7. The system of claim 1, wherein, the flexible actuator extends proximate one or more of a waist of the patient and one or more shoulders of the patient.

8. The system of claim 1, wherein, the flexible actuator forming the artificial muscle contracts in the one direction and simultaneously expands in another direction.

9. The system of claim 1, wherein, the flexible actuator comprises a fluid-driven origami artificial muscle (FOAM) system.

10. The system of claim 9, wherein, the FOAM system includes a Miura fold.

11. The system of claim 1, wherein, the computer system is configured to control adjustment of the flexible actuator in at least two dimensions, and wherein the flexible actuator forms a band extending over at least a portion of the patient, and wherein the at least two dimensions include in-plane contraction across the band and direction transverse to the in-plane direction of the band.

12. A system for delivering radiotherapy to a patient, the system comprising: a radiotherapy source configured to deliver radiotherapy to a patient using a fixed beam during a radiotherapy procedure; a patient support structure configured to receive the patient during the radiotherapy procedure; a patient positioning system configured to adjust a position of the patient support structure relative to the radiotherapy source; a flexible actuator configured to secure the patient to the patient support and adjust a position of at least a portion of the patient relative to the patient support, wherein the flexible actuator forms an artificial muscle that contracts in one direction; an imaging system configured to acquire imaging data of the patient, the patient support, and the flexible actuator during the radiotherapy procedure; and a computer system configured to: control adjustment of the flexible actuator in at least one dimension; receive the imaging data and direct the patient positioning system to adjust a position of the patient support structure during the radiotherapy procedure and direct the flexible actuator to secure the patient and reposition at least a portion of the patient relative to a radiotherapy plan as the patient positioning system adjusts the position of the patient support structure. the radiotherapy source is a particle radiotherapy system.

13. The system of claim 12, wherein, the computer system is further configured to direct a controller to adjust the flexible actuator to counteract a gravitational force acting on the patient as the patient positioning system adjusts the position of the patient support structure relative to the radiotherapy source.

14. The system of claim 12, wherein, the computer system is further configured to direct the controller to adjust the flexible actuator to reposition the patient to correct for a gravitational force acting on the patient as the patient positioning system adjusts the position of the patient support structure relative to the radiotherapy source.

15. The system of claim 12, wherein, the flexible actuator forming the artificial muscle contracts in the one direction and simultaneously expands in another direction.

16. The system of claim 12, wherein, the flexible actuator comprises a fluid-driven origami artificial muscle (FOAM) system.

17. The system of claim 12, wherein, the computer system is configured to control adjustment of the flexible actuator in at least two dimensions, and 18. The system of claim 12, wherein, wherein the flexible actuator forms a band extending over at least a portion of the patient, and wherein the at least two dimensions include in-plane contraction across the band and direction transverse to the in-plane direction of the band. the portion of the patient includes a target region identified in the radiotherapy plan.

19. The system of claim 12, wherein, 20. A computer system for performing a method of constraining and repositioning a patient during a radiotherapy procedure, the method comprising the steps of: i) determining a current position of a patient on a patient support, wherein the patient is positioned to receive radiotherapy from a radiotherapy source during a radiotherapy procedure that follows a radiotherapy plan, the radiotherapy plan including a relative position of the patient relative to the radiotherapy source; ii) acquiring imaging data of the patient, the patient support, and a flexible actuator configured to secure the patient to the patient support and adjust a position of at least a portion of the patient relative to the patient support, wherein the flexible actuator forms an artificial muscle that contracts in one direction; ii) repositioning the patient during the radiation therapy using a patient positioning system configured to adjust a patient support structure relative to the radiation therapy source; iii) controlling a flexible actuator that secures the patient to the patient support and adjusts the patient's position relative to the patient support using a controller to control the adjustment of the flexible actuator in at least one dimension, wherein the flexible actuator forms an artificial muscle that contracts in one direction; iv) acquiring imaging data of the patient, the patient support, and the flexible actuator during the radiation therapy; and v) analyzing the imaging data in relation to the radiation therapy plan to determine an updated position of the patient relative to the radiation therapy plan; and vi) repositioning the patient using the flexible actuator to match a further updated position of the patient to the radiation therapy plan.

21. The computer system of claim 20, further comprising controlling the adjustment of the flexible actuator in at least two dimensions.

Images