Patient positioning for fiducial-free irradiation therapy

Abstract

Methods and systems for positioning and positioning a patient for irradiation therapy without fiducial markers. Platform settings including parameters of the patient support platform are obtained. Platform position data is obtained in which a patient is placed on a platform for imaging without fiducial markers, the platform position data including 3D coordinates of the platform relative to an imager coordinate system calibrated to a predefined fixed set of initialized coordinates in a treatment room. Target tissue is imaged with the patient on the platform. A treatment plan is generated based on the target tissue imaging. The treatment plan comprises a treatment radiation field of a treatment angle, and the treatment angle comprises a platform positioning parameter. When treatment is initiated, the patient is placed on the platform without fiducial markers according to the platform settings. In accordance with the treatment plan, the platform position data, and a coordinate system transformation of the imager coordinate system to the treatment room coordinate system, the platform is adjusted to position the patient at the placement position in the treatment room such that the target tissue is positioned at the isocenter of the treatment room.

Description

Technical Field

[0001] This disclosure generally relates to the field of irradiation therapy, and more specifically to patient registration and platform alignment for irradiation therapy in the absence of reference markers.

[0002] background Teletherapy is defined as a treatment method in which an irradiation source is located at a distance from the body to be treated. X-rays and electron beams have long been used in teletherapy to treat various cancers. Unfortunately, X-rays exhibit linear energy transfer with an exponential decay function, making them the least safe for deeply embedded growths. The use of heavy particles, particularly hadrons, and especially protons, in teletherapy has found increasing acceptance due to the ability of heavy particles to penetrate to specific depths without significantly damaging intermediate tissues. Specifically, the linear energy transfer of hadrons exhibits an inverse depth distribution, where a prominent Bragg peak is defined as the point where hadrons deposit most of their energy and occurs at the end of the hadron path. For electrons, the Bragg peak is not observable due to high scattering. For protons with energies below approximately 70 MeV, scattering significantly suppresses the Bragg peak. As a result of this effect, higher energies can be directed onto embedded growths compared to X-rays and electron beams, which are particularly damaging to intermediate tissues. While the term "hadron" encompasses a wide range of particles, in practice, protons and various ions are the most widely used in therapy. For clarity, this article will describe treatments performed with protons; however, this is not intended to limit the scope of the treatment in any way.

[0003] Protons or ions can be focused onto a target volume with a variable depth of penetration. In this way, the dose distribution can be precisely matched to the target volume. Specifically, a proton beam can be conformed to the shape and depth of the target mass (e.g., a tumor) to avoid irradiating healthy body tissue while delivering a lower whole-body radiation dose. Therefore, compared to conventional external beam therapy, proton therapy allows for a gradually increasing dose, which can be particularly beneficial for certain treatments, such as eye tumors or skull base and paravertebral tumors. Proton therapy also enables highly precise treatment planning with reduced side effects, such as for pediatric treatment or prostate cancer treatment. To ensure complete irradiation of the target mass, multiple beams are typically applied from several different directions to the embedded mass. Regardless of whether the multiple beams are fired sequentially or simultaneously, the point where the multiple beams intersect is called the "isocenter." To maximize bioefficiency, the isocenter must precisely coincide with the target mass.

[0004] Irradiation therapy is performed on the target tissue in a clearly defined process. During the initial phase, the target tissue is imaged and a treatment plan is established. The treatment plan includes a series of treatment fields, each defining at least the dose parameters, target tissue location and orientation, and irradiation angle for each irradiation dose. Prior to imaging and treatment planning, the coordinate system of the imaging device is reset near the target tissue, for example, by a radiation therapy technician. Based on the initial coordinates of the imaging device, placement or reference markers are defined relative to the patient to guide the patient's positioning during treatment. Multiple reference markers are typically applied, such as markers applied to the patient's skin or fixation attachments, for example, a set of three markers, to achieve three-dimensional (3D) positioning. The markers can be formed or highlighted using non-erasable markings or radiopaque materials to facilitate their visualization on the imaging device. The markers are typically designed to last for at least a minimum period, such as weeks or months, to persist throughout the planned treatment duration. For example, reference markers can be in the form of dotted ink tattoos. In subsequent phases, in response to the established treatment plan, irradiation is performed over a period of time in multiple treatment sessions. During treatment, care must be taken to ensure proper positioning of the patient relative to the reference markers to ensure that the applied radiation dose is properly targeted and to avoid damage to organs near the target tissue. Patient positioning relative to the markers is performed based on visualization of the patient relative to the defined markers.

[0005] During a treatment session, the patient is moved to an initial setup position via a positioning support platform, such that a reference marker converges with the isocenter of the treatment room. The treatment plan is then executed with respect to this setup position, where the target tissue is positioned at the isocenter of the treatment room. The patient is then repositioned relative to the setup position according to the treatment plan requirements. Specifically, the target tissue is sequentially repositioned relative to the beam nozzle of a radiation beam delivery device, which may have a fixed position or be capable of limited movement, for example, by means of a gantry. The isocenter of the treatment room can be designated by visual indicators, such as multiple laser beams. Image-guided radiotherapy (IGRT) techniques can be used to verify the accuracy of patient positioning. Stabilization mechanisms can be applied to ensure that the patient's position relative to the isocenter is maintained during treatment, such as using a mask or shield to immobilize the patient's face or body parts.

[0006] Besides being time-consuming and cumbersome to apply, skin marking can be associated with a variety of complications. Skin markings can be considered unsightly and may lead to allergic reactions or skin infections. The persistent and visible nature of these markings can also have negative social or psychological effects, such as serving as a visual reminder of the presence of a disease. Some patients may refuse marking for reasons ranging from cultural and personal beliefs to cosmetic concerns. Some patients follow religious beliefs that prohibit any form of skin marking or tattooing. Older patients may feel distressed about skin marking due to social stereotypes. Other patients may be particularly self-conscious, such as younger women, and may object to skin marking for aesthetic or cosmetic reasons.

[0007] While most medical practitioners will try to avoid marking patients on conspicuous or obviously exposed body parts, even such attempts may not always be feasible. Although reference marks can be removed, the process may be associated with discomfort or physical defects such as scarring. Furthermore, if the patient is to receive further irradiation therapy, removing reference marks may hinder the localization of previous treatment fields and make it more difficult to localize new treatment fields.

[0008] Some baseline markers may not be clearly visible on all skin types. Severe freckles or dark pigmentation can hinder the use of baseline skin markers, which may blend into the skin tone or disappear within a sea of ​​freckles or moles. Baseline markers can be achieved alternatively using invisible materials that do not emit light in the visible light range (such as ultraviolet (UV) inks that emit light when exposed to UV light) instead of using clearly visible markers (such as color-based markers). However, even invisible markers have some of the disadvantages outlined above.

[0009] Irradiation therapy is typically administered when the patient is in a recumbent or supine position, where the patient's body is substantially horizontal and aligned with the ground, supported by a platform surface below. For example, a supine patient may be in a supine position with their back against the surface below and their face upward, or in a prone position with their chest against the surface below and their face downward. However, some treatments may be difficult to perform on horizontally positioned patients, for example, due to the location of the mass within the body, and such treatments may require or be more easily performed in an upright or non-horizontal position. Therefore, the patient may be positioned on a recliner that can be repositioned and reoriented along multiple axes in three-dimensional space (e.g., along six degrees of freedom). Upright or sitting positions can also provide greater patient comfort compared to supine positions, such as for patients with respiratory complications. Furthermore, upright positions may influence changes in the volume, position, and / or movement of body organs (e.g., lungs and heart) compared to supine positions, which may have beneficial effects in certain clinical situations.

[0010] Patients receiving treatment in a lying position typically remain still because the irradiation therapy equipment can be repositioned relative to the patient. However, patients receiving treatment in an upright or non-horizontal position often move during the treatment session, making accurate patient positioning and alignment particularly important.

[0011] Overview According to one aspect of this disclosure, a method is thus provided for positioning and locating a patient for irradiation therapy without reference markers. The method includes the steps of: obtaining a platform setup including parameters for a patient support platform for supporting the patient during irradiation therapy; and obtaining platform position data for the support platform, wherein the patient is positioned on the support platform for imaging without reference markers, the platform position data including 3D coordinates of the support platform relative to an imager coordinate system of an imager calibrated to a predefined and fixed set of initial coordinates in a treatment chamber. The method further includes the steps of: imaging target tissue of the patient on the support platform using the imager, and generating a treatment plan based on the imaging of the target tissue, the treatment plan including a plurality of treatment fields, each of the treatment fields including a treatment angle, the treatment angle including at least one platform positioning parameter of the support platform for positioning the patient such that the target tissue is positioned at the isocenter of the treatment chamber. When irradiation therapy begins, the method further includes the following steps: placing the patient on the support platform without reference markers according to the platform setup; and adjusting the support platform to position the patient at a placement position in the treatment room, such that the target tissue is positioned isocenter in the treatment room, based on the treatment plan, the platform position data, and a coordinate system transformation from the imager coordinate system to the room coordinate system. The method may further include determining the coordinate system transformation by: imaging a dedicated imaging phantom using the imager, the dedicated imaging phantom including multiple markers positioned at known locations relative to the room coordinate system; identifying the phantom markers in the imaging of the imaging phantom; determining the phantom coordinate system in the imager coordinate system based on the positions of the phantom markers; and determining the transformation from the imager coordinate system to the room coordinate system based on the phantom coordinate system and the known positions of the phantom markers relative to the room coordinate system. The method may further include a step of verifying the patient's positioning after moving the support platform to position the patient. Verifying the patient's positioning may include capturing multiple orthogonal stereoscopic X-ray images and adjusting the patient's positioning based on the captured X-ray images. Verifying patient positioning may include imaging the patient to generate a therapeutic imaging model, identifying differences between the therapeutic imaging model and a reference imaging model generated from the initial imaging, and adjusting patient positioning based on the identified differences. The support platform may be adjustable using a platform adjuster configured to rotate at least one platform surface about at least one axis of rotation, or to displace at least one platform surface along at least one axis of displacement. The patient support platform may include a chair, and the patient may be seated. Irradiation therapy may include proton irradiation therapy.The steps of imaging target tissue may include sequentially repositioning and reorienting a movable imager relative to a stationary patient to acquire multiple images at multiple imaging angles.

[0012] According to another aspect of this disclosure, a system is thus provided for positioning and locating a patient for irradiation therapy without reference markers. The system includes a processor configured to obtain platform settings including parameters for a patient support platform for supporting the patient during irradiation therapy, and configured to obtain platform position data of the support platform, wherein the patient is positioned on the support platform for imaging without reference markers, the platform position data including 3D coordinates of the support platform relative to an imager coordinate system calibrated to a predefined and fixed set of initial coordinates in a treatment chamber. The system includes an imager configured to image target tissue of the patient on the support platform. The processor is further configured to generate a treatment plan based on the imaging of the target tissue, the treatment plan including a plurality of treatment fields, each of the treatment fields including a treatment angle including at least one platform positioning parameter of the support platform for positioning the patient such that the target tissue is positioned isocenter in the treatment chamber. When the irradiation treatment begins, the patient is positioned on the support platform without reference markers according to the platform setup, and the processor is configured to instruct adjustments of the support platform to position the patient in a placement position within the treatment room, based on the treatment plan, the platform position data, and a coordinate system transformation from the imager coordinate system to the room coordinate system, such that the target tissue is positioned isocenter within the treatment room. The processor may be configured to determine the coordinate system transformation based on imaging a dedicated imaging phantom, including multiple markers positioned at known locations relative to the room coordinate system, using the imager; identifying phantom markers in the imaging of the imaging phantom; determining the phantom coordinate system within the imager coordinate system based on the positions of the phantom markers; and determining the transformation from the imager coordinate system to the room coordinate system based on the phantom coordinate system and the known positions of the phantom markers relative to the room coordinate system. The system may also include a positioning verifier configured to verify the patient's positioning after the support platform has been moved to position the patient. The positioning verifier may include multiple orthogonally aligned X-ray imagers, and verifying patient positioning may include capturing multiple orthogonal stereoscopic X-ray images and adjusting patient positioning based on the captured X-ray images. Verifying patient positioning may include imaging the patient to generate a therapeutic imaging model, identifying differences between the therapeutic imaging model and a reference imaging model generated based on the initial imaging, and adjusting patient positioning based on the identified differences. The platform adjuster may be configured to rotate at least one platform surface of the platform about at least one rotation axis, or to displace at least one platform surface of the platform along at least one displacement axis. The imager may include a computed tomography (CT) scanner.The imager may be a movable imager configured to be sequentially repositioned and reoriented relative to a stationary patient to acquire multiple images at multiple imaging angles. The patient support platform may include a chair, and the patient may be in a seated position. Irradiation therapy may include proton irradiation therapy. Brief description of the attached diagram This disclosure will be more fully understood and appreciated from the following detailed description, in conjunction with the accompanying drawings, in which: Figure 1 This is a schematic diagram of an irradiation therapy system constructed and operated according to an embodiment of this disclosure; Figure 2 These are schematic diagrams illustrating different coordinate systems used for positioning and locating a patient for irradiation therapy without reference markers, according to embodiments of this disclosure; and Figure 3 This is a flowchart of a method for positioning and locating a patient for irradiation therapy without reference markers, operating according to embodiments of the present disclosure.

[0014] Detailed description of the embodiments This disclosure overcomes the shortcomings of the prior art by providing a novel method and system for positioning a patient for irradiation therapy without reference markers, to achieve proper patient positioning for treatment, particularly upright alignment, without the need for pre-applying reference markers to or around the patient, and without requiring a time-consuming calibration process to ensure correct positioning of different treatment positions, different patient support platforms, and / or different subjects.

[0015] Unless otherwise stated, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosed subject matter pertains. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having the same meaning as they have in the context of the specification and claims and will not be interpreted as having an idealized or overly formal meaning, unless expressly defined as such herein. For the sake of brevity and / or clarity, well-known functions or structures may not be described in detail.

[0016] It should be understood that although the terms first, second, etc., may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. Rather, these terms are used only to distinguish one element, component, region, layer, and / or part from another element, component, region, layer, and / or part.

[0017] It should be understood that when a component is referred to as being "on," "attached" to, "operably coupled" to, "operably linked" to, "operably engaged" with, "connected" to, "joined" with, "contacts" with, or "added to" another component, it can be directly on, attached to, connected to, operably coupled to, operably engaged with, joined to, added to, and / or in contact with the other component, or there may be intermediate components. Conversely, when a component is referred to as "directly contacting" or "directly adding" to another component, there are no intermediate components and / or steps.

[0018] Whenever the terms “about” or “approximately” are used, they are intended to refer to a measurable value, such as a quantity, duration, etc., and are intended to cover variations that deviate from the specified value, as such variations are appropriate for performing the disclosed method.

[0019] For clarity, certain features of the disclosed subject matter described in the context of a single embodiment may also be provided in combination in that single embodiment. Conversely, various features of this disclosure described in the context of a single embodiment for the sake of brevity may also be provided individually or in any suitable sub-combination, or deemed suitable for any other described embodiments of this disclosure. Certain features described in the context of multiple embodiments are not considered essential features of those embodiments unless the embodiment does not function without those elements.

[0020] Whenever the terms "plurality" and "a plurality" are used, they are intended to include, for example, "multiple" or "two or more". The terms "plurality" or "a plurality" may be used throughout the specification to describe two or more parts, devices, elements, units, parameters, etc. The term "set," when used herein, may include one or more items. Unless expressly stated otherwise, the method embodiments described herein are not limited to a particular order or sequence. Furthermore, some of the method embodiments described, or some of their elements, may occur or be performed synchronously, at the same point in time, or simultaneously.

[0021] Throughout this disclosure, references to "disclosed embodiments," "disclosed systems," and "disclosed methods" refer to examples of the inventive ideas, concepts, and / or manifestations described herein. The fact that some disclosed embodiments are described as exhibiting features or characteristics does not imply that other disclosed embodiments must share those features or characteristics.

[0022] This disclosure uses open-source language to indicate, for example, that certain embodiments "may" employ, involve, or include certain features. The use of the term "may" and other open-source terms is intended to indicate that while not every embodiment may employ a particular disclosed feature, at least one embodiment employs a particular disclosed feature.

[0023] The term “operator” is used herein to refer to any individual or group of people operating the methods or systems according to the disclosed embodiments, such as a practicing physician (e.g., a radiation oncologist, radiation therapy nurse, medical radiation physicist, radiation therapist, dosimeter, etc.) involved in performing and / or planning irradiation therapy procedures.

[0024] The terms “subject” and “patient” are used interchangeably herein and refer to an individual toward whom the methods or systems according to the disclosed embodiments are performed, such as a person undergoing an irradiation therapy procedure. A subject can be any living entity, such as a person, human, or animal, characterized in that its body tissues have undergone irradiation therapy.

[0025] The terms “proton therapy” and “proton treatment” are used interchangeably herein to broadly encompass all forms of particle therapy or hadron therapy that apply an excited beam of ionized particles for radiotherapy purposes, including but not limited to protons, neutrons, and other types of ions (all of which are considered to be covered herein by the term “proton”). The terms “irradiation therapy” and “irradiation treatment” as used herein encompass proton therapy and other treatments involving the application of radiation.

[0026] The disclosed subject matter will become apparent from the following detailed description, which is carried out with reference to the accompanying drawings, wherein like reference numerals denote like elements. For a better understanding of certain embodiments and to show how they can be implemented, reference will now be made to the accompanying drawings by way of example only, throughout which similar reference numerals denote corresponding elements or portions.

[0027] Now for reference Figure 1 This is a schematic diagram of an irradiation therapy system (generally designated 110) constructed and operated according to embodiments of the present disclosure. The therapy system 110 includes an irradiation beam generator 112, an irradiation beam delivery device 114, a main imager 116, a positioning verifier 117, a processor 118, a database 119, a patient support platform 122, and a platform adjuster 124. The processor 118 is communicatively coupled to the beam generator 112, the beam delivery device 114, the imager 116, the positioning verifier 117, the database 119, and the platform adjuster 124. The therapy system 110 is configured to be deployed to treat a patient 120 in a treatment room 100, which typically has shielding characteristics to limit radiation penetration outside the treatment field. Some components of the system 110 may reside outside the room 100.

[0028] The patient support platform 122 is configured to support the patient 120 during a treatment session or planning phase. In one embodiment, the patient support platform 122 includes a recliner, allowing the patient 120 to be seated and supported by a pelvic support member 121 (e.g., a seat) and a back support member 123 (e.g., a backrest). Figure 1 (Illustrated in the diagram). The patient support platform 122 may also include or be converted into a bed, allowing the patient 120 to be positioned in a supine or lying position supported by a bed (i.e., horizontal to the ground). The patient support platform 122 is mounted on an adjustable platform base 126 coupled to a platform adjuster 124. The pelvic support member 121 may be tilted relative to the platform base 126, such as defining an angle of tilt relative to a vertical axis (e.g., 10° tilt). The back support member 123 may be tilted relative to the platform base 126, such as defining an angle of tilt relative to a horizontal axis (e.g., 20° tilt).

[0029] Platform adjuster 124 is configured to adjust the position and / or orientation of platform 122 to correspondingly change the position and / or orientation of patient 120 along six degrees of freedom (6DOF). Platform adjuster 124 may include rotation adjustment mechanisms and / or translation adjustment mechanisms, the rotation adjustment mechanism being configured to adjust at least one rotation angle of platform 122 (e.g., pitch, yaw, roll rotation), and the translation adjustment mechanism being configured to translate platform 122 along at least one axis. For example, platform adjuster 124 may include a first mechanism for adjusting the height of platform base 126, and a second mechanism for rotating platform 122 about pitch, yaw, and roll axes respectively (e.g., by manipulating the orientation of platform base 126) (e.g., tilting patient 120 backward, tilting to the side, or rotating, respectively). For example, the rotation adjustment mechanism can rotate platform 122 (or platform base 126) about three orthogonal axes 125R, 127R, and 129R, wherein the first axis 125R is parallel to the floor 102 of the treatment room 100, the second axis 127R is parallel to the floor 102 and orthogonal to the first axis 125R, and the third axis 129R is orthogonal to the floor 102. Rotation of the patient support platform 122 causes the patient 120 to rotate about three orthogonal axes 125P, 127P, and 129P, wherein the first axis 125P is parallel to the longitudinal axis of platform base 126, the second axis 127P is parallel to the longitudinal axis of platform base 126 and orthogonal to the first axis 125P, and the third axis 129P is orthogonal to the longitudinal axis of platform base 126. In one embodiment, axes 125P, 127P, and 129P correspond to axes 125R, 127R, and 129R, respectively.

[0030] The irradiation beam generator 112 includes components and techniques for generating a proton beam for irradiation therapy, such as a particle accelerator. For example, generator 112 may include a cyclotron or synchrotron particle accelerator.

[0031] The irradiation beam delivery device 114 includes components and techniques for delivering at least one irradiation dose 115 from a generated proton beam to a patient 120. For example, the delivery device 114 may be operated using a pencil beam scanning (PBS) mechanism. The delivery device 114 may optionally be coupled to a rotatable stage (not shown) configured to position and orient beam nozzles in 3D space around multiple axes for guiding the delivered irradiation dose 115 to a selected location and orientation (i.e., a selected isocenter). Alternatively, the treatment system 110 may operate without a rotatable stage, which provides increased flexibility for treatment of different anatomical sites and can facilitate the upright positioning of the patient 120.

[0032] Imager 116 is configured to image patient 120, such as during treatment planning and / or treatment sessions. For example, imager 116 may be a medical imaging device used in a medical treatment setting, including but not limited to: computed tomography (CT) imagers, four-dimensional computed tomography (4DCT), X-ray computed tomography (X-ray CT) scanners, optical coherence tomography (OCT) scanners, magnetic resonance imaging (MRI) scanners, and ultrasound imagers. Typically, imager 116 may include any type of imaging sensor capable of acquiring and storing image representations of objects or scenes. Therefore, the term "image" as used herein refers to any form of output from such imager, including any optical or digital representation of a scene acquired at any wavelength or spectral region, and includes single image frames and sequences of image frames (i.e., "video images"). An image rotation mechanism (not shown) may be configured to rotate imager 116 about at least one axis to enable imaging from a selected direction or viewpoint.

[0033] Positioning verifier 117 is configured to verify that patient 120 is properly positioned in a designated placement for treatment. Positioning verifier 117 may be embodied, for example, by an X-ray imaging device comprising a set of complementary X-ray emitter and detector pairs located around the treatment isocenter, wherein the respective pairs are perpendicularly aligned with each other (i.e., to achieve three-dimensional positioning). The X-ray imaging device may be mounted on the wall or floor of treatment room 100. Alternative methods for position verification may include surface-guided radiotherapy (SGRT) 3D imaging technology and cone-beam computed tomography (CBCT) imaging technology.

[0034] Processor 118 is configured to selectively control the operation of components of system 110 and to dynamically adjust their operating parameters. Processor 118 is also configured to receive and provide instructions and data to / from components of system 110 and to perform the necessary data processing.

[0035] Database 119 stores relevant information to be retrieved and processed by processor 114, such as captured images. Database 119 can be implemented by one or more local servers or by remote and / or distributed servers, such as in a cloud storage platform.

[0036] Information can be transmitted between components of system 110 using any type of channel or network model and any data transmission protocol (e.g., wired, wireless, radio, WiFi, Bluetooth, etc.) via any suitable data communication channel or network. The components and devices of system 110 can be based on hardware, software, or a combination thereof. It should be understood that the functionality associated with each device or component of system 110 can be distributed across multiple devices or components, which can reside in a single location or multiple locations. For example, the functionality associated with processor 118 can be distributed between separate components, such as at least one control unit and at least one processing unit (e.g., which may be part of a server or remote computer system accessible via a communication network, such as a cloud computing platform). Processor 118 can also be integrated, at least partially, with other components of system 110 (e.g., incorporated within a dedicated local control unit).

[0037] System 110 may optionally include Figure 1 Additional components not shown in the figure and / or associated with additional components not shown in the figure are used to enable the disclosed subject matter to be realized. For example, system 110 may include a user interface (not shown) for allowing a user to provide instructions or control various parameters or settings associated with components of system 110, and / or a display device (not shown) for visually displaying information related to the operation of system 110.

[0038] An exemplary workflow for irradiation therapy will now be described in general terms. During the initial session, patient 120 is placed and positioned on a selected support platform 122, which represents the platform on which irradiation therapy will be performed, i.e., the same platform or a platform of similar type. Irradiation therapy can be performed on various support platforms, each of which may have adjustable moving parts and attachments. In one embodiment, platform 122 is a recliner, and patient 120 is supported in an upright or sitting position. When patient 120 is placed on platform 122, parameters or configuration settings for the selected platform 122 are obtained. Platform settings may include platform type (e.g., type of bed or chair), characteristics (e.g., tilted, non-tilted, maximum tilt angle), size, attachments, default position / orientation, etc. Platform settings may include how the patient is placed on the platform and which platform attachments should be used during treatment. For example, some patients (such as patients with short stature) may be positioned on one or more booster pads to elevate their position on the platform. Therefore, platform settings may include booster pad information, such as: whether booster pads are applied; the type of booster pads; and the number and order of booster pads. Another form of platform attachment can be handrails. In this case, the platform settings can include handrail information, such as: whether handrails are used; the angle at which the handrails are aligned; and the height at which the handrails are attached to the platform. The obtained platform settings are stored for later application when setting up and positioning the appropriate patient 120 for treatment.

[0039] The patient 120 is then positioned relative to the imager 116 (e.g., a CT scanner) to allow imaging of the target tissue via the imager 116, for example, by moving the platform 122 into the field of view of the imager 116 and / or adjusting the patient 120's positioning on the platform 122. With the patient 120 correctly positioned for imaging, position data for the platform 122 is obtained. The platform position data may include the 3D position and orientation coordinates of the platform 122 in the coordinate system of the imager 116. A set of initial coordinates for the imager 116 can be defined such that the imager 116 is calibrated to a zero point relative to the chamber, where this point remains fixed during subsequent treatment sessions. This position data can be acquired before and / or during imaging when the platform 122 is in the imaging position. The imager 116 then images the target tissue of the patient 120 to be treated, for example, by capturing multiple images from multiple imaging angles. In one example, imaging is performed using a movable imager 116, such as a portable CT imaging device, which is repositioned and reoriented relative to a stationary patient 120 to acquire images from multiple imaging angles. Imaging can be performed in the treatment room 100 where treatment will be conducted, or in a different location, such as an imaging room, which may contain system elements similar to those in the treatment room 100. For example, the imaging room may contain at least one support platform corresponding to and registered with the actual support platform to be used for patient treatment. Patient imaging can be performed by a first operator, such as a CT imaging technician. Reference markers are not applied to or around the patient 120 at this stage, unlike conventional treatment planning.

[0040] In the subsequent phase, a treatment plan is established. The treatment plan can be executed by a second operator or a treatment planner (such as a medical physicist). The treatment plan can be executed on a later date after patient imaging, in the absence of patient 120. The treatment planner receives a treatment prescription for irradiation therapy for patient 120. The treatment prescription may include details related to the target tissue (e.g., type, shape, size, location in the body) and a recommended dose to be administered to the target tissue (e.g., recommended minimum and / or maximum dose). The treatment planner generates a treatment plan based on the received treatment prescription and the imaging of the target tissue (during an earlier imaging session). The treatment plan may include a series of irradiation parameters or “treatment fields” for at least one treatment session, each treatment field being defined at least by dose parameters, the position and orientation of the target tissue relative to the isocenter, and the irradiation angle for each irradiation dose. The treatment plan may define a series of treatment angles for orienting the corresponding irradiation dose to the target tissue coordinates. The treatment angle can represent “platform positioning parameters” that define the three-dimensional rotation and translation of the support platform 122 for repositioning in a 3D coordinate system, such as rotation relative to the pitch, yaw, and roll axes of the platform base 126, and at least one translation on the displacement axis of the platform base 126. The treatment plan can utilize a three-dimensional model of the target tissue generated from captured images. For example, the target tissue model can be a computed tomography (CT) imaging volume. An auxiliary imaging device, such as stereoscopic imaging, can be used to construct the target tissue imaging volume.

[0041] If necessary, the generated treatment plan can be validated and updated. Validation of the treatment plan can be performed on-site, for example, by an operator physically inspecting and validating the feasibility of the treatment plan's radiation field (e.g., dose, patient positioning, treatment angle) at treatment room 100. After the treatment plan has been completed, irradiation therapy can be performed in one or more treatment sessions. During a treatment session, the patient 120 is brought to treatment room 100 and positioned on support platform 122 according to the platform configuration settings obtained during an earlier imaging phase. Specifically, the patient 120 is positioned and located on platform 122 according to the defining characteristics (tilted, non-tilted, maximum tilt angle), dimensions, attachments (e.g., booster pads, handrails), and other relevant parameters of platform 122. The patient 120 is then moved to the positioning position for treatment according to the treatment plan. Specifically, platform 122 can be moved such that the target tissue of the patient 120 is positioned at the isocenter of treatment room 100. The treatment plan can define the coordinates of the target tissue, such as relative to the imager coordinate system corresponding to imager 116. The patient 120 can be repositioned during a treatment session according to the treatment angles defined in the treatment plan. The treatment angles may include a set of platform positioning parameters or tilt angles in a 3D angular coordinate system for the platform surfaces 121, 123 of platform 122 (i.e., pelvic support member 121 and / or back support member 123), such as corresponding to pitch, yaw, and roll rotations, respectively. For example, a “platform yaw angle” defines the angle at which platform surfaces 121, 123 are aligned with an axis orthogonal to the floor 102, such as left-right rotation (i.e., yaw rotation); a “platform pitch angle” defines the angle at which platform surfaces 121, 123 are aligned with their lateral axis, such as forward or backward tilt rotation (i.e., pitch rotation); and a “platform roll angle” defines the angle at which platform surfaces 121, 123 are aligned with their orthogonal axis, such as left-right pivot rotation (i.e., roll rotation). Platform positioning parameters may also include at least one translational displacement of platform 122 (or platform surfaces 121, 123) along its displacement, such as a height displacement of platform base 126. The treatment angle effectively defines the direction vector by which the irradiation beam 115 is oriented to the target tissue coordinates during the treatment session. The target tissue coordinates can be defined in the field of the treatment plan as the point where the target tissue is located in the imager coordinate system. Typically, the treatment plan defines a sequence of treatment fields for a given treatment session. Each treatment field includes the irradiation dose intensity (dose parameter), irradiation angle, and the position of the target tissue isocenter, which in turn defines a corresponding set of treatment angles or platform positioning parameters for guiding the irradiation dose to the target tissue according to the corresponding irradiation angle and the corresponding target tissue coordinates.

[0042] The patient 120 is positioned for treatment by moving platform 122 within treatment room 100. Within the limitations or constraints of treatment room 100, platform 122 can be moved or repositioned by platform adjuster 124. For example, platform adjuster 124 may include a robotic arm that can be configured to selectively modify the orientation of platform surfaces 121, 123, such as between right-hand and left-hand orientations. Processor 118 can guide platform adjuster 124 to adjust at least one rotational angle (e.g., pitch, yaw, roll rotation) of platform 122, and / or translate platform 122 along at least one axis.

[0043] The patient's target tissue can be positioned isocentrically within the treatment room by a transformation from the imager coordinate system (corresponding to imager 116) to the room coordinate system (corresponding to treatment room 100). This transformation can be established using appropriate processing techniques. Processor 118 can determine the treatment angle based on the treatment plan to position and orient the target tissue relative to the treatment room isocentrically. (Reference) Figure 2 This is a schematic diagram of different coordinate systems used for positioning and locating a patient for irradiation therapy without reference markers, according to embodiments of the present disclosure. A first coordinate system 141 is defined relative to imager 116 and is referred to as the "imager coordinate system". A second coordinate system 142 is defined relative to treatment chamber 100 and is referred to as the "chamber coordinate system". A third coordinate system 143 represents a transformation between imager coordinate system 141 and chamber coordinate system 142 (e.g., derived using applicable mathematical formulas and / or mapping procedures for coordinate transformation) such that each pixel in the target tissue volume (e.g., CT volume) can be addressed to a known physical location within treatment chamber 100. In one example, transformation 143 is determined by scanning a dedicated imaging phantom at a known location (i.e., position and orientation) relative to treatment chamber coordinate system 142 under imager 116. The phantom may include multiple markers, such as nine metallic markers, set at known measurable locations for geolocation. The phantom is imaged by imager 116, and the resulting images (e.g., CT scans) are processed to identify the phantom markers. A new coordinate system within the imager coordinate system 141 can be constructed based on the phantom markers, and a transformation can be determined between the newly constructed coordinate system and the imager coordinate system 141. The resulting transformation can be combined with the known position of the dedicated imaging phantom in the treatment room 100 to obtain the final transformation 143.

[0044] A patient (not shown) is positioned on a support platform 122 and positioned such that the coordinates (e.g., center) of the target tissue are located at the isocenter 150 of the treatment chamber 100. The irradiation dose can be directed to the isocenter 150 via a beam nozzle 134 of an irradiation beam delivery device (not shown). Specifically, position data of the platform 122 relative to the imager coordinate system 141, acquired during the treatment planning phase, is transformed to the treatment chamber coordinate system 142 via an imager-to-treatment chamber transition coordinate system 143 to position the patient for treatment. Thus, the platform 122 is positioned prior to treatment such that the target tissue is located at the treatment chamber isocenter 150 relative to the chamber coordinate system 142, based on the treatment angle extracted from the treatment field of the treatment plan and based on the position data of the platform 122 relative to the imager coordinate system 141 acquired during treatment planning. The patient setup and positioning for treatment can be performed by a third operator or treatment practitioner (e.g., an irradiation therapy technician).

[0045] The positioning of patient 120 to the treatment placement can be verified prior to treatment. One method for verification may include re-imaging patient 120 using imager 116, applying a transformation between the reference model and the treatment model generated by the imager, measuring the differences, and applying corrections accordingly. For example, when using a CT scanner imager, positioning registration can be performed by identifying and correcting the differences between the reference CT volume (on which the treatment plan is based) and the new treatment CT volume (captured during the treatment session). Another method is to move patient 120 directly to the isocenter of the treatment room and then verify correct patient positioning using positioning verifier 117. For example, positioning verifier 117 may include a pair of complementary X-ray emitters and detectors located around the treatment isocenter and vertically aligned to capture at least two X-ray images from orthogonal directions. Based on the captured X-ray images, the positioning of patient 120 can be adjusted according to the desired positioning defined by the treatment plan. In the event of incorrect and / or correct verification, the operator may receive an alarm, for example via visual or auditory notification, to indicate when the patient is incorrectly or correctly positioned.

[0046] Once the positioning has been verified, irradiation therapy can be administered in one or more treatment sessions. Irradiation therapy can target different parts of the patient's body from different directions or angles. Therefore, the patient can be positioned on the support platform with different alignments or anatomical positions relative to the irradiation. For example, irradiation can be directed towards the front of the patient (i.e., such that the patient's back or front faces the beam nozzle of the delivery device 114) or towards the back of the patient (e.g., such that the patient's front or back faces the beam nozzle of the delivery device 114).

[0047] It should be understood that the disclosed embodiments allow for the setup and positioning of patients for irradiation therapy without the prior application of reference markers. The disclosed embodiments allow the operator to accurately position and verify the correct positioning of the patient according to an established treatment plan, while avoiding the need to apply reference markers to the patient during the initial session. In this way, potential complications associated with reference markers, such as allergic reactions, skin infections, aesthetic or cosmetic problems, patient resistance, difficulty perceiving the marker, and byproducts of marker removal, can be avoided. The time-consuming and cumbersome process of applying markers can also be avoided. It should also be understood that the disclosed embodiments can provide reference marker-free patient positioning for irradiation therapy of patients in upright or non-horizontal (e.g., sitting) positions.

[0048] refer to Figure 3 This is a flowchart of a method for positioning and locating a patient for irradiation therapy without reference markers, operating according to embodiments of the present disclosure. In step 172, a platform setup for a support platform for supporting the patient for irradiation therapy is obtained. (See reference...) Figure 1 The processor 118 receives platform configuration settings including parameters for supporting the support platform 122 for supporting the patient 120 during irradiation therapy. The platform settings may include parameters related to: platform type, platform characteristics (e.g., tilted, non-tilted, maximum tilt angle), default position and orientation; platform dimensions; platform accessories (e.g., booster pads, armrests); and how to position the patient 120 on the platform 122.

[0049] In step 174, platform position data of the support platform is obtained, wherein the patient is positioned on the platform for imaging without reference markers. (Reference) Figure 1 and Figure 2 The processor 118 receives platform position data from the platform 122, wherein the patient 120 is positioned on the platform 122 without reference markers and is positioned for imaging of target tissue by the imager 116. The platform position data may include the 3D coordinates (position and orientation) of the platform 122 relative to the imager coordinate system 141 of the imager 116, which is calibrated to a predefined and fixed set of initialized (zero-point) coordinates in the chamber 100. The platform position data may also include the alignment of the patient 120 relative to the platform 122, for example, depending on the type of treatment or the location of the target tissue.

[0050] In step 176, the target tissue of the patient on the support platform is imaged. (Reference) Figure 1The imager 116 images the target tissue of the patient 120 while the patient is supported on the platform 122 in the imaging position and aligned. For example, the imager 116 captures multiple images from multiple imaging angles, from which a target tissue imaging volume can be generated. Imaging can be performed using a movable imager 116 (such as a movable CT imaging device) that is repositioned and reoriented relative to the stationary patient 120.

[0051] In step 178, a treatment plan is generated based on imaging. Specifically, the treatment planner receives a treatment prescription for irradiation therapy of patient 120, such as target tissue features and a recommended dose to be applied to the target tissue, and generates a treatment plan based on the treatment prescription and target tissue imaging. The treatment plan may include a series of treatment fields for at least one treatment session. Each treatment field may include at least the irradiation dose intensity (dose parameter), target tissue coordinates, and irradiation angle for each irradiation dose. The treatment plan may define a series of treatment angles for guiding the corresponding irradiation dose to the target tissue according to the corresponding irradiation angle. The treatment angles may include platform positioning parameters that define a set of rotation angles and translational displacements in a 3D angular coordinate system for rotating and shifting at least one platform surface 121, 123 of platform 122. Note that steps 172, 174, 176, and 178 may be performed during the pretreatment phase of irradiation therapy.

[0052] In step 180, the patient is placed on the support platform without reference markers, according to the platform settings. (Reference) Figure 1 According to the platform configuration settings (as obtained in step 172), patient 120 is brought to treatment room 100 and placed on support platform 122 during treatment session, where patient 120 has no reference marker.

[0053] In step 182, based on the treatment plan, platform position data, and coordinate transformation from the imager coordinate system to the treatment room coordinate system, the platform is adjusted to position the patient in the treatment room. (Reference) Figure 1 and Figure 2The operator (i.e., the treatment practitioner) moves the patient 120 to a positioning position within the treatment room 100, such that the isocenter of the target tissue is located at the isocenter of the treatment room 100 according to the treatment plan (generated in step 178) and the position data of the platform 122 (obtained in step 174). The patient 120 can be moved to the positioning position for treatment by adjusting the platform 122 using the platform adjuster 124. Specifically, the platform adjuster 124 can adjust the position and orientation of the platform 122 according to the defined treatment angle of the corresponding treatment field of the treatment plan, for example by applying pitch, yaw, and roll rotations to the platform surfaces 121, 123 of the platform 122, and / or by applying at least one translational displacement, so as to position the platform 122 at the defined treatment angle. The positioning of the target tissue relative to the treatment room isocenter 150 can be performed according to a transformation from the imager coordinate system 141 (corresponding to the imager 116) via a transformation coordinate system 143 to the room coordinate system 143 (corresponding to the treatment room 100). Specifically, platform 122 is positioned such that the target tissue is positioned at the center 150 of the treatment room relative to the chamber coordinate system 142, based on the treatment angle extracted from the treatment field of the treatment plan and based on the position data of platform 122 relative to imager coordinate system 141. According to one embodiment, patient 120 is positioned on platform 122 in an upright or seated position. Coordinate transformation 143 can be determined in advance using an imaging phantom. Specifically, imager 116 is used to image a dedicated imaging phantom comprising multiple markers (e.g., nine markers) set at known locations relative to chamber coordinate system 142. The phantom markers are identified in the image, and a phantom coordinate system in the imager coordinate system is established based on the known locations of the phantom markers. Then, a transformation 143 from imager coordinate system 141 to chamber coordinate system 142 is established based on the phantom coordinate system and the known locations of the phantom markers relative to chamber coordinate system 142.

[0054] In step 184, patient localization is verified. (See reference) Figure 1 The operator verifies, for example, by using a positioning verifier 117 to confirm that the patient is properly positioned in the treatment setup. For instance, the positioning verifier 117 can capture multiple X-ray images from orthogonal directions and can adjust the patient's positioning based on the captured X-ray images to ensure correct positioning at the treatment angle according to the corresponding treatment field of the treatment plan. Alternatively, the operator can verify patient positioning by re-imaging the patient 120 using imager 116, identifying the difference between the imager reference model (e.g., the reference CT volume on which the treatment plan is based) and the newly acquired treatment CT volume, and correcting the positioning as needed based on the identified difference. Stabilizing mechanisms can be applied to ensure that the patient's positioning is maintained relative to the isocenter during treatment, such as using a mask or shield to immobilize the patient 120's face and / or other body parts.

[0055] In step 186, irradiation therapy is performed after verifying patient localization. (Reference) Figure 1 Based on the sequence of treatment fields in the generated treatment plan, patient 120 receives at least one radiation dose during the treatment session. The irradiation treatment may be targeted at at least one body part of patient 120 and may be directed to the anterior or posterior side of patient 120. Assistive imaging (such as using a positioning verifier 117) may be applied during the treatment application session to ensure that the characteristics of the target tissue have not changed significantly since the start of treatment (this may require modification of the treatment plan).

[0056] In step 188, the irradiation therapy session is terminated. (See reference) Figure 1 After the operator applies the final irradiation dose to patient 120 according to the final treatment field for the corresponding session in the generated treatment plan, the treatment session ends. Irradiation treatment of patient 120 can continue during subsequent treatment sessions. Steps 180, 182, 184, 186, and 188 can be performed during the treatment phase of irradiation treatment.

[0057] While certain embodiments of this disclosure have been described to enable those skilled in the art to practice the disclosed subject matter, the foregoing description is intended to be exemplary only. It should not be used to limit the scope of the disclosed subject matter, which should be determined by reference to the appended claims.

Claims

1. A method for positioning and locating a patient for irradiation therapy without reference markers, the method comprising the following steps: Obtain platform settings, which include parameters for a patient support platform used to support patients during irradiation therapy; Obtain platform position data of the support platform, wherein the patient is placed on the support platform for imaging without reference markers, the platform position data including the 3D coordinates of the support platform relative to the imager coordinate system of the imager, the imager being calibrated to a predefined and fixed set of initial coordinates in the treatment room; The imager is used to image the target tissue of the patient on the support platform. A treatment plan is generated based on the imaging of the target tissue. The treatment plan includes multiple treatment fields, each of which includes a treatment angle. The treatment angle includes at least one platform positioning parameter of the support platform for positioning the patient so that the target tissue is positioned at the isocenter of the treatment room. When the irradiation treatment begins, the patient is placed on the support platform without reference markers, according to the platform settings. and Based on the treatment plan, the platform position data, and the coordinate transformation from the imager coordinate system to the treatment room coordinate system, the support platform is adjusted to position the patient at the placement position in the treatment room, so that the target tissue is positioned at the isocenter of the treatment room.

2. The method of claim 1, further comprising determining the coordinate system transformation by imaging a dedicated imaging phantom using the imager, the dedicated imaging phantom comprising a plurality of markers positioned at known locations relative to the chamber coordinate system; Identify phantom markers in the imaging of the phantom; The phantom coordinate system in the imager coordinate system is determined based on the position of the phantom markers. Furthermore, the transformation from the imager coordinate system to the chamber coordinate system is determined based on the known positions of the phantom coordinate system and the phantom markers relative to the chamber coordinate system.

3. The method of claim 1, further comprising verifying the patient's location after moving the support platform to locate the patient.

4. The method according to claim 3, wherein, Verifying patient positioning involves capturing multiple orthogonal stereoscopic X-ray images and adjusting the patient's positioning based on the captured X-ray images.

5. The method according to claim 3, wherein, Verifying patient localization includes: imaging the patient to generate a therapeutic imaging model, identifying differences between the therapeutic imaging model and a reference imaging model generated based on the initial imaging, and adjusting patient localization based on the identified differences.

6. The method according to claim 1, wherein, The patient support platform can be adjusted using a platform adjuster configured to rotate at least one platform surface about at least one rotation axis and to displace at least one platform surface along at least one displacement axis.

7. The method of claim 1, wherein the patient support platform is a chair, and wherein the patient is in a seated position.

8. The method of claim 1, wherein the irradiation therapy comprises proton irradiation therapy.

9. The method according to claim 1, wherein, The steps for imaging the target tissue include sequentially repositioning and reorienting the movable imager relative to a stationary patient to acquire multiple images from multiple imaging angles.

10. A system for positioning and locating a patient for irradiation therapy without reference markers, the system comprising: A processor configured to obtain platform settings including parameters for a patient support platform for supporting a patient during irradiation therapy, and configured to obtain platform position data of the support platform, wherein the patient is positioned on the support platform for imaging without reference markers, the platform position data including 3D coordinates of the support platform relative to the imager coordinate system of the imager, the imager being calibrated to a predefined and fixed set of initial coordinates in the treatment room; and An imager configured to image target tissue of a patient on the support platform. The processor is further configured to generate a treatment plan based on imaging of the target tissue. The treatment plan includes multiple treatment fields, each including a treatment angle. Each treatment field includes at least one platform positioning parameter of the support platform for positioning the patient such that the target tissue is positioned isocenter within the treatment room. When the irradiation treatment begins, the patient is placed on the support platform without reference markers according to the platform settings, and the processor is configured to instruct the adjustment of the support platform to position the patient in the treatment room according to the treatment plan, the platform position data, and the coordinate transformation from the imager coordinate system to the room coordinate system of the treatment room, such that the target tissue is positioned at the isocenter of the treatment room.

11. The system according to claim 10, wherein, The processor is configured to: determine the coordinate system transformation based on imaging a dedicated imaging phantom, including multiple markers positioned at known locations relative to the chamber coordinate system, using the imager; and identify the phantom markers in the imaging of the imaging phantom. The phantom coordinate system in the imager coordinate system is determined based on the position of the phantom marker; and the transformation from the imager coordinate system to the room coordinate system is determined based on the known position of the phantom coordinate system and the phantom marker relative to the room coordinate system.

12. The system of claim 10, further comprising a positioning verifier configured to verify the patient's positioning after the support platform has been moved to position the patient.

13. The system of claim 12, wherein the positioning verifier comprises a plurality of orthogonally aligned X-ray imagers, and wherein verifying the patient's positioning comprises capturing a plurality of orthogonal stereoscopic X-ray images and adjusting the patient's positioning based on the captured X-ray images.

14. The system according to claim 12, wherein, Verifying patient localization includes: imaging the patient to generate a therapeutic imaging model, identifying differences between the therapeutic imaging model and a reference imaging model generated based on the initial imaging, and adjusting patient localization based on the identified differences.

15. The system of claim 10, further comprising a platform adjuster configured to rotate at least one platform surface of the platform about at least one rotation axis and to displace at least one platform surface of the platform along at least one displacement axis.

16. The system according to claim 10, wherein, The imager includes a computed tomography (CT) scanner.

17. The system according to claim 10, wherein, The imager includes a movable imager configured to be sequentially repositioned and reoriented relative to a stationary patient to acquire multiple images at multiple imaging angles.

18. The system of claim 10, wherein the patient support platform is a chair, and wherein the patient is in a seated position.

19. The system of claim 10, wherein the irradiation therapy comprises proton irradiation therapy.

Images