Hybrid continuous positive pressure and surface imaging system and method

Abstract

To provide a hybrid continuous positive pressure and surface imaging system for use in a radiotherapy system.SOLUTION: The hybrid continuous positive pressure and surface imaging system includes: a positive pressure unit adapted to apply a continuous positive pressure to lungs of a patient during radiotherapy; a surface camera system configured to continuously, or at intervals, capture body surface images of the patient; and a processing unit configured to continuously, or at intervals, model chest and / or abdominal movement of the patient in response to the applied continuous positive pressure based on the body surface images.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a hybrid continuous positive pressure and surface imaging system for use in a radiation therapy system. The present disclosure further relates to a computer-implemented method for providing real-time feedback to a positive pressure unit. [Background technology]

[0002] Radiation therapy is a therapy that uses ionizing radiation, typically delivered by a linear accelerator, commonly provided as part of cancer treatment to control or kill malignant cells. Radiation therapy can be curative in many types of cancer when localized to one area of ​​the body. The radiation of the radiation beam does not distinguish between healthy and malignant cells and can therefore damage both healthy and malignant cells. As a result, the radiation beam must generally be precisely constructed and directed at the target site of the malignant tumor to focus the accumulated radiant energy on the malignant tumor and minimize the accumulation of radiant energy in the surrounding healthy tissue.

[0003] Conventional procedures for delivering radiant energy by a therapeutic radiation beam to malignant tumors that exhibit motion during irradiation can include forming a beam large enough so that the malignant tumor remains within the beam cross section throughout the entire irradiation process. Respiration-induced tumor motion is a challenge for radiotherapy of tumors in the thorax. One strategy to address this challenge is to create an internal target volume (ITV) that models the tumor trajectory and allows the patient to breathe freely during treatment. However, this approach is associated with a larger volume of normal lung tissue receiving the ablative dose of radiation compared to other motion management strategies.

[0004] More recently, continuous positive airway pressure (CPAP) has been investigated as an alternative strategy to reduce tumor motion during radiation therapy. Although CPAP was originally developed for other purposes, such as the treatment of obstructive sleep apnea, and as a non-invasive alternative to intubation and other invasive techniques used in conditions such as pulmonary edema, it has been shown to be effective in reducing tumor motion during radiation therapy. It may be used in combination with other techniques to address respiration-induced tumor motion. This has a particularly powerful role in heavy ion radiation of tumors in the chest, where motion results in inadequate dose deposition. However, there are also many challenges associated with this technique. One example is determining the optimal CPAP pressure for a particular patient, which is a difficult and time-consuming task. Anxiety can also have a significant effect on breathing patterns. Summary of the Invention

[0005] The present disclosure provides a hybrid continuous positive pressure and surface imaging system for use in a radiation therapy system, comprising: a positive pressure unit (PPU) adapted to apply continuous positive pressure to the patient's lungs during radiation therapy; a surface camera system configured to capture images of the patient's body surface continuously or at intervals; and a processing unit configured to model continuous or intervalwise movement of the patient's chest and / or abdomen in response to the applied continuous positive pressure based on the body surface image.

[0006] The inventors have recognized that by using a surface camera system to capture a patient's body surface image continuously or at intervals and modeling the chest and / or abdominal movements continuously or at intervals, a system with substantially real-time feedback to the PPU is preferably provided. This has several advantages and possible applications. Determining the optimal CPAP pressure for a particular patient is a difficult and time-consuming task. The disclosed system allows for a CPAP training process outside the radiation treatment room prior to radiation treatment, and only a PPU, a surface camera system and a processing unit are required.

[0007] Radiation therapy typically involves a planning or simulation process. The simulation may be performed in a simulation room, which may be the same as the treatment room. The simulation may include, for example, scanning, patient positioning and alignment with the radiation therapy beam, and preparation for the complete radiation therapy session, where dose is calculated and modeling of the target and organs at risk is performed. The hybrid continuous positive pressure and surface imaging system of the present disclosure may be used as an integral part of a radiation therapy system, but may also be used independently outside of the radiation therapy room prior to a radiation therapy session.

[0008] A surface camera system and processing unit configured to model the patient's chest and / or abdominal movements, either continuously or at intervals, provides a system that can be used to train the patient to reliably reproduce a stable shallow breathing pattern with limited tidal volumes and limited chest wall and / or abdominal movements to achieve the same conditions during both simulation and treatment. The system can provide signals representative of chest wall / abdominal movements that are sensitive to small changes in CPAP pressure. The effectiveness of the PPU in maintaining chest position throughout the respiratory cycle can be determined by the hybrid continuous positive pressure and surface imaging system. A feedback mechanism, preferably substantially real-time, allows the operator to adjust the positive pressure to the point where chest movements are within predetermined limits. This may be done, according to one embodiment, by automatically increasing the pressure in a controlled manner over a predetermined ramp period until chest movements are within predetermined limits or until the pressure reaches a predetermined limit.

[0009] The system may also be used to detect and monitor paradoxical and unpredictable increases in chest wall and abdominal movement in anxious patients. A further application of the hybrid continuous positive pressure and surface imaging system may be where the system provides feedback for synchronization of the radiation beam and / or suspends operation of the radiation beam in response to deviations in the height, shape, or movement of the patient's chest and / or abdomen from the expected height, shape, or movement of the patient's chest and / or abdomen, or deviations in the surface caused by changes in lung volume.

[0010] The positive pressure unit may typically comprise an air pump unit, a flow tube and a control unit configured to control the positive pressure unit. The positive pressure unit may further comprise a power source such as a rechargeable battery and a wireless communication unit for communicating with the surface camera system directly or via a further unit. The processing unit may be located in either the positive pressure unit and the surface camera system or in the further unit. The positive pressure unit may be configured to flatten and reduce the movement of the diaphragm during breathing, expanding the lungs and thoracic cavity.

[0011] The surface camera system configured to capture the patient's body surface images continuously or at intervals may include one or more three-dimensional cameras and / or one or more two-dimensional cameras. The processing unit may be configured to model the movement of the patient's chest and / or abdomen continuously or at intervals based on the body surface images from the cameras. There are several possible techniques and camera systems that can be used as the surface camera system, including those provided by Vision RT and described in several previous patents and patent applications, including U.S. Pat. No. 7,889,906, U.S. Pat. No. 7,348,974, U.S. Pat. No. 8,135,201, U.S. Patent Application Publication No. 2015 / 062303, U.S. Patent Application Publication No. 2015 / 0265852, U.S. Patent Application Publication No. 2020 / 0184625, U.S. Pat. No. 10,441,818, U.S. Patent Application Publication No. 2016 / 0256710, the disclosures of which are incorporated herein by reference.

[0012] In a non-limiting example, a three-dimensional model of a patient's surface is generated utilizing several stereoscopic video images of at least the patient's thoracic and / or abdominal regions, which are processed to generate the three-dimensional model of the thoracic and / or abdominal regions and are rapidly updated to account for changes in motion of the thoracic and / or abdominal regions.

[0013] In order to be able to update the surface model of the patient as quickly as possible, several techniques can be utilized. In one embodiment, there is provided an image processing method comprising the steps of acquiring a volumetric image of an individual, utilizing said volumetric image to generate a surface model of said individual, receiving a further volumetric image of said individual and generating a further model of said individual from said further volumetric image and said previous model of said individual.

[0014] According to one non-limiting embodiment, a speckle pattern of light is projected onto the surface of the patient's chest and / or abdominal region to facilitate identification of corresponding portions of the patient's surface captured from different perspectives. Images of the patient are acquired and processed along with data identifying the relative position of the camera capturing the image to identify 3D locations of a number of points corresponding to points on the patient's surface. Another example of a surface camera system monitors the position of a patient undergoing radiation therapy by projecting structured light (e.g., laser light) in the form of a line or grid pattern or other predefined pattern onto the patient's surface and generating a model of the surface on the patient being monitored based on the appearance of the projected pattern in the captured images. Based on the model of the surface, which may be the surface of the patient's chest and / or abdominal region, the movement of the patient's chest and / or abdominal region can be continuously modeled.

[0015] The present disclosure further provides a computer-implemented method for providing real-time feedback to a positive pressure unit, comprising: acquiring continuous positive pressure data from continuous positive pressure applied to the patient's lungs during radiation therapy; capturing continuous or interval images of the patient's body surface using a surface camera system; and c) modeling, continuously or at intervals, chest and / or abdominal movement of the patient in response to the applied continuous positive pressure based on the body surface image.

[0016] As will be appreciated by one of ordinary skill in the art, the computer-implemented method of the present disclosure for providing real-time feedback to a positive pressure unit may be performed using any embodiment of the hybrid continuous positive pressure and surface imaging system of the present disclosure, and vice versa. [Brief description of the drawings]

[0017] The present invention will now be described with reference to the accompanying drawings, which are exemplary of embodiments and are not limiting of the hybrid continuous positive pressure and surface imaging system and computer-implemented method of providing real-time feedback to a positive pressure unit as disclosed herein.

[0018] [Figure 1] 1 is an embodiment of a hybrid continuous positive pressure and surface imaging system of the present disclosure for use in a radiation therapy system. [Diagram 2] 1 is a flowchart of a method for providing real-time feedback to a positive pressure unit according to an embodiment of a computer-implemented method of the present disclosure. [Diagram 3] FIG. 1 illustrates a front perspective view of an embodiment of a surface camera system. [Figure 4] FIG. 1 is a schematic block diagram of an embodiment of a processing unit of the hybrid continuous positive pressure and surface imaging system of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present disclosure provides a hybrid continuous positive pressure and surface imaging system for use in a radiation therapy system, comprising: a positive pressure unit (PPU) adapted to apply continuous positive pressure to the patient's lungs during radiation therapy; a surface camera system configured to continuously capture body surface images of the patient; and a processing unit configured to continuously model chest and / or abdominal movement of the patient in response to the applied continuous positive pressure based on the body surface image.

[0020] The description of the embodiments of the hybrid continuous positive pressure and surface imaging system of the present disclosure is provided by way of example and is not intended to limit the scope of the invention. The described embodiments include different features, not all of which are necessarily required in all embodiments of the invention. Some embodiments utilize only some of the features or possible combinations of the features. Variations of the described embodiments of the invention, and embodiments of the invention including different combinations of the features described in the described embodiments, will occur to those skilled in the art.

[0021] By using a surface camera system to continuously capture body surface images of the patient and continuously modeling chest and / or abdominal movements, a system with real-time feedback to the PPU is obtained. This has several advantages and possible applications. For example, it allows the use of a portable PPU. Determining the optimal CPAP pressure for a particular patient is a difficult and time-consuming task. The disclosed system can allow for a CPAP training or preparation process outside of the radiation treatment room before radiation treatment, where only a PPU, a surface camera system and a processing unit are required. The portable PPU can continue to be used after the CPAP training or preparation process, thereby maintaining controlled breathing. The device can be transported or carried between the radiation treatment room and a second location or room.

[0022] The inventors have recognized that by using a surface camera system to continuously capture body surface images of a patient and continuously modeling chest and / or abdominal movements, a system is preferably provided with substantially real-time feedback to the PPU. This has several advantages and possible applications. Determining the optimal CPAP pressure for a particular patient is a difficult and time-consuming task. The disclosed system allows for a CPAP training process outside of the radiation treatment room prior to radiation treatment, with only a PPU, a surface camera system and a processing unit being required.

[0023] "Continuously" is intended to be interpreted broadly to include receiving a series of images and modeling at any suitable rate. In this regard, as one example, it is well known that a series of still images at a given rate creates the illusion of a moving image. This can translate to the hybrid continuous positive pressure and surface imaging systems and methods of the present disclosure in the sense that a surface camera system can be configured to capture images of the patient's body surface at a rate.

[0024] FIG. 1 illustrates a non-limiting example of a hybrid continuous positive pressure and surface imaging system (100) for use in a radiation therapy system (200). The radiation therapy system (200) may be any suitable radiation therapy system and may typically include a radiation beam generator, such as a gated radiation beam generator, which typically comprises a linear particle accelerator adapted to generate a radiation beam for irradiating a target volume. The gated radiation beam generator is typically an external device or system. The radiation therapy system may further comprise a controller for controlling the beam generator. The radiation therapy system may be a conventional two-dimensional beam system, but may also be, for example, a three-dimensional beam system, an intensity modulated radiation therapy IMRT system, or a volumetric modulated arc therapy VMAT system, or a heavy particle beam system, such as a proton or carbon ion beam-based system. In the example of FIG. 1, a radiation beam 210 is generated towards a target 320, which may be a tumor in a patient 300 positioned on a couch 150. The positive pressure unit 110 is configured to apply continuous positive pressure to the lungs of the patient 300 during radiation therapy treatment. The positive pressure unit 110 comprises an air pump unit 111 and a flow tube 112 connected to the airway of the patient 300 via a face mask 113. The surface camera system 120 is configured to continuously capture body surface images of the patient 300, in particular surface images of the thoracic and / or abdominal region 310 of the patient 300. The processing unit 130 is configured to continuously model the thoracic and / or abdominal movements of the patient 300 in response to the applied continuous positive pressure based on the body surface images obtained from the surface camera system 120. The control unit 140 is configured to control the positive pressure unit 110 and / or the radiation therapy system 200.

[0025] The processing unit is configured to continuously extract an amplitude metric that can be translated into chest and / or abdominal movement. The amplitude metric may be any suitable metric, such as a change in height of the patient's chest wall or abdomen. The chest wall height may be understood as the component perpendicular to the patient's chest surface. The height is indicated by "h" in FIG. 1. The abdominal height may be understood as the component perpendicular to the patient's abdominal surface.

[0026] The processing unit may be configured to continuously model chest and / or abdominal movement in six degrees of freedom (6DOF) based on images from the surface camera system. "6DOF" generally refers to the degrees of freedom of motion of a rigid body in three-dimensional space. Specifically, the body is free to change position as forward / backward (surge), up / down (heave), left / right (sway) translations in three perpendicular axes, often combined with changes in orientation through rotations about three perpendicular axes called yaw (vertical axis), pitch (lateral axis), and roll (longitudinal axis). The processing unit may be configured to continuously model chest and / or abdominal movement based on body surface images acquired from the surface camera system.

[0027] In one embodiment, the processing unit is configured to continuously extract the amplitude of chest height movement during a respiratory cycle. The processing unit may alternatively or additionally be configured to detect deviations in height, shape or movement of the patient's chest and / or abdomen. Extraction of the patient's chest height, shape or movement may be extracted from a model of chest and / or abdomen movement, for example from chest and / or abdomen movement modeled continuously with six degrees of freedom (6DOF).

[0028] In one embodiment, the processing unit is configured to distinguish between patient motion and chest and / or abdominal motion. Based on a model of a surface, which may be the surface of the patient's chest and / or abdominal region, or based on a comparison with other modeled criteria of the patient for example, the system may distinguish between general patient motion and local chest and / or abdominal motion. The processing unit may be configured to distinguish between patient motion and chest and / or abdominal motion based on the modeled chest and / or abdominal motion of the patient. The processing unit may be configured to distinguish between patient motion and chest and / or abdominal motion based on the body surface image.

[0029] Feedback from the surface camera system can be used in many applications. In one embodiment, the control unit is configured to optimize the continuous positive pressure to minimize chest and / or abdominal movement of the patient based on the continuously modeled chest and / or abdominal movement of the patient. As will be appreciated by those skilled in the art, the control unit and the processing unit may be provided as separate devices or as one unit. The control unit and the processing unit may form part of any of the other parts of the system, such as the surface imaging system, the radiation therapy system, and the positive pressure unit. The control unit may be configured to optimize the continuous positive pressure to minimize chest and / or abdominal movement of the patient based on the body surface images. The control unit may be configured to optimize the continuous positive pressure to minimize chest and / or abdominal movement of the patient based on the modeled chest and / or abdominal movement of the patient.

[0030] The hybrid continuous positive pressure and surface imaging system may be configured to continuously model the patient's chest and / or abdominal movement in substantially real time. This may be done, for example, by acquiring body surface images of the patient, particularly of the patient's chest and / or abdominal regions, and using the body surface images in a physiological model of the patient to model the chest and / or abdominal movement. The body surface images may then be converted into a model of the chest and / or abdominal volume using the physiological model of the patient.

[0031] The hybrid continuous positive pressure and surface imaging system of the present disclosure may further comprise a control unit configured to control the continuous positive pressure and maintain chest and / or abdominal movement within predetermined limits. Thus, the monitoring feedback mechanism may allow an operator to adjust the positive pressure until the chest movement is within the defined limits or is minimized. The monitoring feedback mechanism may allow automatic adjustment of the positive pressure until the chest movement is within the defined limits or is minimized. This is typically done within a set-up environment, but if excessive chest movement is detected within the treatment room, the pressure may be adjusted to correct this. In one embodiment, the continuous positive pressure is gradually increased until chest and / or abdominal movement is within the defined limits. For example, the positive pressure may be automatically increased in a controlled manner over a defined ramp period to avoid until a consistent chest position is achieved or the positive pressure reaches a defined limit. The control unit may be configured to control the continuous positive pressure to maintain chest and / or abdominal movement within the defined limits based on the body surface image. The control unit may be configured to control the continuous positive pressure based on modeled thoracic and / or abdominal movement of the patient to maintain thoracic and / or abdominal movement within predetermined limits.

[0032] The positive pressure unit preferably includes an air pump unit and a flow tube. The air pump unit may comprise a blower. In one embodiment, the positive pressure unit comprises an airway connected to a blower with integral attachments for pressure and volume measurement, and a nozzle for attachment of a hose. The PPU may further comprise a control unit configured to control the positive pressure unit. In one embodiment, the control unit provides a signal for adjustment of the continuous positive pressure provided by the positive pressure unit. For example, the speed of the blower may be controlled by pulse width modulation (PWM), which allows fine speed adjustment and provides a signal proportional to the fan speed. Other suitable methods for controlling the positive pressure unit are possible. The PPU can detect pressure fluctuations and adjust the fan speed accordingly to maintain the desired pressure.

[0033] The positive pressure unit may be configured to apply air pressure to the patient's airways to expand the lungs and lift the chest, minimizing chest movement during the radiation therapy treatment process. This provides the advantage of stabilizing the position of the chest while simultaneously moving the heart away from the left breast. This also increases lung volume, redistributing normal lung tissue away from the dose and reducing tumor movement in the lungs. During radiation treatment, this has the advantage of reducing unintended lung and heart dose.

[0034] The positive pressure unit may be configured to perform a procedure at a target site within the thoracic or abdominal region of the patient's body and to constrain movement of the target site due to respiratory motion during the procedure. The positive pressure unit may be configured to provide continuous positive airway pressure to the patient's lungs during and / or prior to the radiation therapy treatment to constrain movement of the target site, expand the thoracic cavity and lungs, and / or displace organs and tissues within the thoracic cavity away from the target site.

[0035] The hybrid continuous positive pressure and surface imaging system may further comprise a pressure measurement unit for measuring lung pressure. The processing unit may be configured to compare the measured lung pressure with an expected lung pressure. The processing unit may further be configured to verify a discrepancy between the measured lung pressure and the expected lung pressure for the continuously modeled chest and / or abdominal movements. If there is a discrepancy between the measured pressure and the expected measurement, an error condition may be flagged. This may be signaled to the control unit, which may inform the operator. Similarly, a beam hold may be signaled to the radiotherapy system. The measurement unit may further be adapted to measure lung volume and / or from around the mask or in connection to the mask. The positive pressure unit may further comprise a power source, such as a rechargeable battery, and a wireless communication unit for communicating with the surface camera system, directly or via a further unit. The PPU may be a portable PPU.

[0036] The disclosed hybrid continuous positive pressure and surface imaging system may be configured to store patient-specific pressure settings for individual patients. This may allow for reproducibility of breathing patterns. The disclosed hybrid continuous positive pressure may continuously measure and / or monitor several parameters. For example, if the measured pressure is outside a predetermined tolerance range or the tidal volume exceeds a predetermined tolerance range, an error condition may be flagged. The hybrid continuous positive pressure and surface imaging system may include a watchdog, for example in the form of an application running on the processing unit that checks at intervals for pressure at the PPU or an error condition from the PPU. When transitioning between the setup room and the treatment room, the watchdog may be disabled for a pre-set period of time.

[0037] CPAP can be configured to operate to flatten the diaphragm during breathing, reducing its movement and expanding the lungs and thoracic cavity. CPAP can thereby mitigate movement of tissues and organs in the thoracic and abdominal regions due to the patient's breathing, and, as a result, movement of the target of the radiation therapy system during irradiation. The expansion of the lungs and thoracic cavity tends to rearrange and increase the spacing between the organs in the thoracic cavity and abdomen. The reduction in the movement of the target site and other organs and tissues in the patient's thoracic and abdominal regions facilitates the delivery of a medical device or agent to the target site and contributes to a reduction in possible collateral damage to tissues outside the target site resulting from the delivery of the medical device or agent. The expansion of the lungs and thoracic cavity and the resulting rearrangement and spacing of organs within the thorax and abdomen can also facilitate the delivery of a medical device or agent to the target site and a reduction in possible collateral damage to tissues outside the target site resulting from the delivery of the medical device or agent.

[0038] The surface camera system configured to continuously capture body surface images of the patient may comprise one or more three-dimensional cameras and / or one or more two-dimensional cameras. The processing unit may be configured to continuously model the movement of the patient's chest and / or abdomen based on the body surface images from the cameras. There are several possible techniques and camera systems that can be used as the surface camera system, including systems provided by Vision RT.

[0039] The surface camera system, by way of non-limiting example, may be adapted to provide a volumetric body surface image of a patient, whereby the volumetric images of the patient can be acquired and processed to generate data identifying the 3D positions of a number of points corresponding to points on the imaged surface of the patient.

[0040] An example of an embodiment of a surface camera system is shown in FIG. 3. FIG. 3 is a front perspective view of an exemplary surface camera system 120. The surface camera system 120 in this example comprises a housing 123 connected to a bracket 121 via a hinge 122. The bracket 121 allows the surface camera system 120 to be mounted in a fixed position on the ceiling of a treatment room, while the hinge 122 allows the orientation of the surface camera system 120 to be oriented relative to the bracket 121 so that the surface camera system 120 can be positioned to view a patient 300 on a couch 150. A pair of lenses 125L / 125R are attached to opposite ends of the front surface 124 of the housing of the surface camera system 120. These lenses 125L / 125R can be positioned in front of an image capture device / camera, such as a CMOS active pixel sensor or a charge-coupled device (not shown), housed within the housing 123. A camera / image detector is preferably positioned behind lenses 125L / 125R to capture an image of patient 300 through lenses 125L / 125R.

[0041] In this example, the speckle projector 126 is provided in the center of the front surface 124 of the housing 123 between the two lenses 125L / 125R of the surface camera system 120 shown in FIG. 3. The speckle projector 126 in this example is configured to illuminate the patient 300 with a non-repetitive speckle pattern of light, such as red light, so that when images of the patient 300 are captured by the two image detectors mounted in the surface camera system 120, corresponding portions of the captured images can be more easily distinguished. To that end, the speckle projector comprises a light source, such as an LED, and a film on which a random speckle pattern is printed. In use, light from the light source is projected through the film, so that a pattern of light and dark areas is projected onto the surface of the patient 300. In some monitoring systems, the speckle projector 126 may be replaced by a projector arranged to project structured light (e.g., laser light) in the form of a line or grid pattern onto the surface of the patient 300.

[0042] 4 is a schematic block diagram of an example of the processing unit 130. In order for the processing unit 130 to process the images received from the surface camera system 120, the processing unit 130 is configured by software provided on a disk or by receiving an electrical signal via a communication network to several functional modules 131-135. In this example, the functional modules 131-135 comprise a 3D positioning module 131 for processing the images received from the surface camera system 120, a model generation module 132 for processing the data generated by the 3D positioning module 131 and converting the data into a 3D wire mesh model of the imaged computer surface, a generative model storage 133 for storing the 3D wire mesh model of the imaged surface, a target model storage 134 for storing previously generated 3D wire mesh models, and a matching module 135 for determining the rotation and translation required to match the generative model with the target model. In use, as images are acquired by the surface camera system 120, these images are processed by the 3D positioning module 131. This processing enables the 3D position determination module 131 to identify 3D positions of corresponding points in pairs of images on the surface of the patient 300. In the exemplary system, this is accomplished by the 3D position determination module 131 identifying corresponding points in pairs of images acquired by the surface camera system, and then determining the 3D positions of those points based on the relative positions of the corresponding points in the pairs of acquired images and the stored camera parameters for the surface camera system 120.

[0043] The hybrid continuous positive pressure and surface imaging system of the present disclosure is not limited to the above examples of the surface camera system 120 and the processing unit 130. A further example of a surface imaging system comprises a sheet that may be placed on the patient, for example, on the patient's chest and / or abdominal surface. Preferably, at least a portion of the sheet is colored. The surface camera system may be operable to acquire images of the patient and the sheet. The model generation module may be operable to process the images acquired by the surface camera system to generate a model of the surface of the portion of the patient that appears in the images. In some embodiments, the system may further comprise a projector operable to project a pattern of light onto the patient. In such an embodiment, preferably, the colored portion of the sheet is positioned to absorb a significant proportion of the projection light projected by the projector such that the projected pattern is not easily visible in the portion of the image corresponding to the sheet. This may be achieved by making the color of the sheet substantially black so as to absorb a substantial proportion of the projected light. In other embodiments, the color of the sheet may be selected to correspond to a color associated with the wavelength of the projected light such that the projection of the light onto the surface of the sheet is not easily visible. In some embodiments, the sheet may be colored black.

[0044] The surface camera system may be adapted to provide a volumetric body surface image of the patient. The processing unit may therefore be configured to process the volumetric body surface image and generate a model of the surface of the patient's chest.

[0045] The radiation therapy system may be a conventional two-dimensional beam system, but may also be, for example, a three-dimensional beam system, an intensity modulated radiation therapy (IMRT) system, or a volumetric modulated arc therapy (VMAT) system. The radiation therapy system may be an external beam radiation therapy system. There are many techniques available, including conventional external beam radiation therapy using medical linear accelerators. Typically, the treatment is simulated before the treatment. The goal of the simulation is to accurately target or localize the volume to be treated. The technique is well established and is generally fast and reliable. A challenge is that some high-dose treatments may be limited by the radiation toxicity capabilities of healthy tissues near the target tumor volume. Other types of radiation therapy systems are stereotactic radiosurgery, intensity modulated radiation therapy, and volumetric modulated arc therapy. The present hybrid continuous positive pressure and surface imaging system is not limited to any particular type of radiation therapy system. A radiation therapy system may typically include a radiation beam generator adapted to generate a radiation beam for irradiating a target volume.

[0046] Additional systems, such as fluoroscopy-based systems, can be used to track tumor movement.

[0047] The control unit may be configured to interrupt operation of the radiation beam when the extracted height or shape of the patient's chest and / or abdomen deviates with respect to an expected height or shape of the patient's chest and / or abdomen. In a further embodiment, the control unit is configured to synchronize the radiation beam with the extracted height or shape of the patient's chest.

[0048] The present disclosure further relates to a computer-implemented method of providing real-time feedback to a positive pressure unit, the method including the steps of obtaining continuous positive pressure data from continuous positive pressure applied to a patient's lungs during radiation therapy, continuously capturing body surface images of the patient using a surface camera system, and continuously modeling chest and / or abdominal movement of the patient in response to the applied continuous positive pressure based on the body surface images.

[0049] FIG. 2 shows a flow chart of a method according to an embodiment of a computer-implemented method of the present disclosure for providing real-time feedback to a positive pressure unit (400). The method includes acquiring (410) continuous positive pressure data from continuous positive pressure applied to the patient's lungs during radiation therapy, continuously capturing (420) body surface images of the patient using a surface camera system, and continuously modeling (430) the patient's thoracic and / or abdominal movement in response to the applied continuous positive pressure based on the body surface images. The method may further include applying a continuous positive pressure to the patient's lungs during radiation therapy. The method may further include optimizing the continuous positive pressure to minimize the patient's thoracic and / or abdominal movement and / or to control the continuous positive pressure to maintain the thoracic and / or abdominal movement within predetermined limits.

[0050] The method may be implemented as a computer program having instructions that, when executed by a computing device or computing system, cause the computing device or computing system to perform the method of providing real-time feedback to the positive pressure unit. The non-transitory storage medium may include a computer program product having instructions embodied therein that, when executed by a computing device or computing system, cause the computing device or computing system to provide real-time feedback to the positive pressure unit.

Claims

1. 1. A hybrid continuous positive pressure and surface imaging system for use in a radiation therapy system, comprising: a positive pressure unit adapted to apply continuous positive pressure to the patient's lungs during radiation therapy; a surface camera system configured to capture, continuously or at intervals, images of the patient's body surface; and a processing unit configured to model, continuously or at intervals, chest and / or abdominal movement of the patient in response to the applied continuous positive pressure based on the body surface image.

2. The hybrid continuous positive pressure and surface imaging system of claim 1 , wherein the processing unit is configured to extract, continuously or at intervals, amplitude metrics that can be converted to chest and / or abdominal movement.

3. The hybrid continuous positive pressure and surface imaging system of claim 1 , wherein the processing unit is configured to extract the height of the patient's chest wall and / or abdomen continuously or at intervals.

4. 10. The hybrid continuous positive pressure and surface imaging system of claim 1, wherein the processing unit is configured to model chest and / or abdominal movements in six degrees of freedom (6 DOF), either continuously or at intervals.

5. The hybrid continuous positive pressure and surface imaging system of claim 1 , wherein the processing unit is configured to extract changes in amplitude of chest and / or abdominal height movement during a respiratory cycle.

6. The hybrid continuous positive pressure and surface imaging system of claim 1 , wherein the processing unit is configured to detect deviations in height, shape or movement of the chest and / or abdomen of the patient.

7. The hybrid continuous positive pressure and surface imaging system of claim 1 , wherein the processing unit is configured to distinguish between patient movement and chest and / or abdominal movement based on the body surface images.

8. 10. The hybrid continuous positive pressure and surface imaging system of claim 1, further comprising a control unit configured to optimize the continuous positive pressure based on the body surface image to minimize movement of the patient's chest and / or abdomen.

9. 10. The hybrid continuous positive pressure and surface imaging system of claim 1, wherein the processing unit is configured to model chest and / or abdominal movement of the patient continuously or at intervals substantially in real time.

10. 10. The hybrid continuous positive pressure and surface imaging system of claim 1, further comprising a control unit configured to control the continuous positive pressure based on the body surface image to maintain the chest and / or abdominal movement within predetermined limits.

11. 11. The hybrid continuous positive pressure and surface imaging system of claim 10, wherein the continuous positive pressure is gradually increased until the chest and / or abdominal movement is within the predetermined limits.

12. The hybrid continuous positive pressure and surface imaging system of claim 1 , wherein the positive pressure unit comprises an air pump unit and a flow tube.

13. The hybrid continuous positive pressure and surface imaging system of claim 12 , wherein the air pump unit includes a blower.

14. The hybrid continuous positive pressure and surface imaging system of claim 1 , further comprising a control unit configured to control the positive pressure unit based on the body surface image.

15. The hybrid continuous positive pressure and surface imaging system of claim 14 , wherein the control unit provides signals for regulation of the continuous positive pressure provided by the positive pressure unit.

16. The hybrid continuous positive pressure and surface imaging system of claim 1 , further comprising a pressure measurement unit for measuring pulmonary pressure.

17. 17. The hybrid continuous positive pressure and surface imaging system of claim 16, wherein the processing unit is configured to compare a measured lung pressure with an expected lung pressure, and the processing unit is further configured to validate any discrepancy between the measured lung pressure and the expected lung pressure against continuously modeled chest and / or abdominal movement.

18. The hybrid continuous positive pressure and surface imaging system of claim 1 , wherein the surface camera system is adapted to provide a stereoscopic body surface image of the patient.

19. 20. The hybrid continuous positive pressure and surface imaging system of claim 18, wherein the processing unit is configured to process the volumetric body surface images and generate a model of the thoracic and / or abdominal surface of the patient.

20. The hybrid continuous positive pressure and surface imaging system of claim 1 , further comprising a radiation beam generator, such as a gated radiation beam generator, adapted to generate a radiation beam for irradiating the target volume.

21. 21. The hybrid continuous positive pressure and surface imaging system of claim 20, wherein the control unit is configured to interrupt operation of the radiation beam in response to deviations in height, shape or movement of the patient's chest and / or abdomen from an expected height, shape or movement of the patient's chest and / or abdomen, or deviations in surface caused by changes in lung volume.

22. 21. The hybrid continuous positive pressure and surface imaging system of claim 20, wherein a control unit is configured to synchronize the radiation beam with an extracted height or shape of the chest and / or abdomen of the patient.

23. The hybrid continuous positive pressure and surface imaging system of claim 20 , wherein the control unit is configured to discontinue operation of the radiation beam if a mismatch occurs.

24. 1. A computer-implemented method for providing real-time feedback to a positive pressure unit, comprising: acquiring continuous positive pressure data from continuous positive pressure applied to the patient's lungs during radiation therapy; capturing continuous or interval images of the patient's body surface using a surface camera system; and modeling, continuously or at intervals, chest and / or abdominal movement of the patient in response to the applied continuous positive pressure based on the body surface image.

25. 25. The computer-implemented method of claim 24, further comprising applying the continuous positive pressure to the patient's lungs during radiation therapy.

26. 25. The computer-implemented method of claim 24, further comprising optimizing the continuous positive pressure to minimize movement of the patient's thoracic and / or abdominal regions and / or controlling the continuous positive pressure to maintain movement of the thoracic and / or abdominal regions within predetermined limits.

27. 25. The computer-implemented method of claim 24, wherein the computer-implemented method is performed using the hybrid continuous positive pressure and surface imaging system of claim 1.

28. 25. A computer program comprising instructions which, when executed by a computing device or computer system, cause the computing device or computer system to perform the computer implemented method of claim 24.

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