Radiotherapy quality assurance device

Abstract

Provided herein is technology relating to quality assurance programs for external radiation therapy beam delivery systems and particularly, but not exclusively, to integrated devices and systems for daily quality assurance testing and validation of beam energy and range and for high precision measurements of beam position, shape, and size.

Description

[0001]ASTO-43522.601 RADIOTHERAPY QUALITY ASSURANCE DEVICE CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of U.S. Provisional Patent Application No. 63 / 674,487 filed July 23, 2024, which is incorporated by reference herein in its entirety. FIELD Provided herein is technology relating to quality assurance programs for external radiation therapy beam delivery systems and particularly, but not exclusively, to integrated devices and systems for daily quality assurance testing and validation of beam energy and range and for high precision measurements of beam position, shape, and size. BACKGROUND Recent radiotherapy systems have been developed that comprise a patient positioning system, a computerized tomography (CT) scanner, and an external radiation therapy beam. See, e.g., U.S. Pat. Nos. 11,529,109 and 11,918,397; and U.S. Pat. App. Pub. No. 2023 / 0172566, each of which is incorporated herein by reference. Quality assurance (QA) systems are used to test and validate the safety, mechanical, dosimetric, and imaging parameters of radiotherapy systems to ensure safe radiation delivery to patients. See, e.g., Ding (2021) “A critical review of the practices of proton daily quality assurance programs” Ther Radiol Oncol 5: 22; Rana (2018) “Development and long‐term stability of a comprehensive daily QA program for a modern pencil beam scanning (PBS) proton therapy delivery system” J Appl Clin Med Phys 20: 29; International Atomic Energy Agency (2004) “Commissioning and Quality Assurance of Computerized Planning Systems for Radiation Treatment of Cancer” IAEA Technical Reports Series No.430; and Arjomandy et al. (2019) “AAPM task group 224: Comprehensive proton therapy machine quality assurance” Med Phys 46: e678 (also known as “TG-224”), each of which is incorporated herein by reference. Previous technologies provide separate QA devices for precision measurements of beam position, shape, and size and for daily QA testing and validation of beam energy and range. See, for instance, the LYNX and SPHINX devices available commercially from IBA Dosimetry and the phantoms available commercially from Logos Systems International. However, integrated radiotherapy systems would benefit from a comprehensive QA technology that obviates the need to use, prepare, and configure multiple devices. ASTO-43522.601 SUMMARY Accordingly, provided herein is technology relating to quality assurance programs for external radiation therapy beam delivery systems and particularly, but not exclusively, to integrated devices and systems for daily quality assurance testing and validation of beam energy and range and for high precision measurements of beam position, shape, and size. The integrated QA devices and systems may also find use in quality assurance testing and validation of daily patient set up using high-resolution diagnostic imaging provided by the CT scanner and optical surface guidance systems for image guided radiation therapy, e.g., as described in Int’l Pat. App. No. PCT / US2024 / 026297, which is incorporated herein by reference. The QA devices and systems described herein find use in calibrating beam delivery, performing acceptance testing, and commissioning of beam delivery systems. Further, the technology described herein provides a cost effective and affordable technology that reduces the costs of radiotherapy facilities. In some embodiments, the technology described herein relates to a quality assurance (QA) device. In some embodiments, the QA device comprises a housing comprising a posterior side and an anterior side; a scintillator screen; a number of beam degrader wedges; a first mirror that is radiolucent; a second mirror; and a camera. In some embodiments, the first mirror comprises a plastic (e.g., a radiolucent plastic). In some embodiments, housing comprises radiolucent materials (e.g., a radiolucent plastic). In some embodiments, the housing is light-tight. In some embodiments, the QA device has a mass of less than 15 Kg (e.g., less than approximately 15.0, 14.5, 14.0, 13.5, 13.0, 12.5, 12.0, 11.5, 11.0, 10.5, or 10.0 Kg). In some embodiments, the scintillator screen is mounted on an internal surface of the posterior side of the housing; the first mirror is oriented to reflect light produced by the scintillator screen toward the second mirror; and the second mirror is oriented to reflect light produced by the scintillator screen and reflected by the first mirror toward the camera. In some embodiments, the first mirror is oriented (e.g., essentially or substantially oriented) at a 45-degree angle with respect to the scintillator screen. In some embodiments, the first mirror is oriented (e.g., essentially or substantially oriented) at approximately a 45-degree angle with respect to the scintillator screen. In some embodiments, the QA device further comprises a computerized tomography phantom. In some embodiments, the QA device further comprises an ion chamber (e.g., a parallel plate ion chamber). In some embodiments, the QA device comprises an ion chamber on the internal surface of anterior side of the housing. In ASTO-43522.601 some embodiments, the QA device further comprises visible lines on an external surface of the housing. In some embodiments, the visible lines mark the center of the radiolucent mirror, the scintillator screen, and / or the plane of the scintillator screen. In some embodiments, the camera is a high-resolution power-over-Ethernet camera. In some embodiments, the scintillator screen has an active measurement area of approximately 20 cm × 20 cm (e.g., approximately 15.0, 15.1, 15.2, 15.3, 15.4, 15.5, 15.6, 15.7, 15.8, 15.9, 16.0, 16.1, 16.2, 16.3, 16.4, 16.5, 16.6, 16.7, 16.8, 16.9, 17.0, 17.1, 17.2, 17.3, 17.4, 17.5, 17.6, 17.7, 17.8, 17.9, 18.0, 18.1, 18.2, 18.3, 18.4, 18.5, 18.6, 18.7, 18.8, 18.9, 19.0, 19.1, 19.2, 19.3, 19.4, 19.5, 19.6, 19.7, 19.8, 19.9, 20.0, 20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 21.0, 21.1, 21.2, 21.3, 21.4, 21.5, 21.6, 21.7, 21.8, 21.9, 22.0, 22.1, 22.2, 22.3, 22.4, 22.5, 22.6, 22.7, 22.8, 22.9, 23.0, 23.1, 23.2, 23.3, 23.4, 23.5, 23.6, 23.7, 23.8, 23.9, 24.0, 24.1, 24.2, 24.3, 24.4, 24.5, 24.6, 24.7, 24.8, 24.9, or 25.0 cm × approximately 15.0, 15.1, 15.2, 15.3, 15.4, 15.5, 15.6, 15.7, 15.8, 15.9, 16.0, 16.1, 16.2, 16.3, 16.4, 16.5, 16.6, 16.7, 16.8, 16.9, 17.0, 17.1, 17.2, 17.3, 17.4, 17.5, 17.6, 17.7, 17.8, 17.9, 18.0, 18.1, 18.2, 18.3, 18.4, 18.5, 18.6, 18.7, 18.8, 18.9, 19.0, 19.1, 19.2, 19.3, 19.4, 19.5, 19.6, 19.7, 19.8, 19.9, 20.0, 20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 21.0, 21.1, 21.2, 21.3, 21.4, 21.5, 21.6, 21.7, 21.8, 21.9, 22.0, 22.1, 22.2, 22.3, 22.4, 22.5, 22.6, 22.7, 22.8, 22.9, 23.0, 23.1, 23.2, 23.3, 23.4, 23.5, 23.6, 23.7, 23.8, 23.9, 24.0, 24.1, 24.2, 24.3, 24.4, 24.5, 24.6, 24.7, 24.8, 24.9, or 25.0 cm). In some embodiments, the beam degrader wedges are made from a plastic (e.g., polyethylene). In some embodiments, the QA device comprises 1, 2, 3, 4, or 5 beam degrader wedges. In some embodiments, the QA device comprises 3 beam degrader wedges. In some embodiments, the first mirror reflects visible light (e.g., having a wavelength of between approximately 380 nm and approximately 750 nm or having an energy of approximately 1.6 eV to approximately 3.3 eV) and transmits a high-energy radiation beam (e.g., having a wavelength of less than 10 nm or an energy of more than 100 eV, more than 1000 eV, more than 10 MeV, or more than 100 MeV). In some embodiments, the high-energy radiation beam comprises x-rays or hadrons. The technology provided herein relates also to methods of performing quality assurance for a radiotherapy system. For instance, in some embodiments, methods comprise providing a quality assurance (QA) device comprising: a housing comprising a posterior side and an anterior side; a scintillator screen; a number of beam degrader wedges; a first mirror that is radiolucent; a second mirror; and a camera; contacting the posterior side of the QA device to provide high precision measurements of beam position, shape, and / or size; and contacting the anterior side of the QA device to provide periodic ASTO-43522.601 measurements of beam energy and / or range. In some embodiments, the periodic measurements are for daily QA testing. In some embodiments, the periodic measurements are for weekly QA testing, monthly QA testing, or yearly QA testing. In some embodiments, the high precision measurements are for calibrating beam delivery, performing acceptance testing, and / or commissioning of a beam delivery system. In some embodiments, the QA device further comprises a computerized tomography phantom. In some embodiments, methods further comprise performing QA testing of a computerized tomography scanner. In some embodiments, methods further comprise testing image guided radiotherapy positioning. In some embodiments, methods further comprise positioning the QA device using or a radiation-based image guidance system. In some embodiments, methods further comprise testing an optical guidance system. In some embodiments, methods further comprise validating a patient set-up system. In some embodiments, methods further comprise placing the QA device on a patient positioning system. In some embodiments, methods further comprise testing laser alignment. In some embodiments, methods comprise providing a quality assurance (QA) device comprising: a housing comprising a posterior side and an anterior side; a scintillator screen; a number of beam degrader wedges; a first mirror that is radiolucent; a second mirror; and a camera; and one or more of: measuring a beam spot size in two dimensions; measuring a beam spot position in two dimensions; measuring the beam spot in air in two dimensions; measuring a beam energy; measuring a monitor unit linearity; measuring an illuminance of a beam spot; measuring a dose uniformity; and / or comparing a test beam parameter value to a baseline beam parameter value or an average of multiple beam parament values acquired over a period of days, weeks, or months. The technology described herein also relates to a quality assurance (QA) system. For example, in some embodiments, systems comprise a quality assurance device comprising a housing comprising a posterior side and an anterior side; a scintillator screen; a number of beam degrader wedges; a first mirror that is radiolucent; a second mirror; and a camera; and a computer. In some embodiments, systems further comprise a computer-readable medium containing computer program code for controlling the system in a QA mode or a precision mode. In some embodiments, systems further comprise a computer-readable medium containing computer program code for acquiring an image from the camera; applying a lens distortion correction to the image; denoising the image; subtracting a background from the image; and applying a pixel correction to the image. In some embodiments, the computer program code for controlling the system ASTO-43522.601 in a QA mode is configured to compare a test image with a reference image; find a centroid, horizontal width, and / or vertical width of a beam spot; and determine a test Bragg peak curve from intensities measured for a beam. In some embodiments, the computer program code for controlling the system in precision mode is configured to acquire an image from the camera; and find a centroid, horizontal width, and / or vertical width of a beam spot in the image. In some embodiments, systems further comprise a computer-readable medium comprising computer program code for a user interface to control the system and / or to accept comparison tolerances for beam spot centroids, horizontal widths, and vertical widths; and for Bragg peak curves. Some portions of this description describe the embodiments of the technology in terms of algorithms and symbolic representations of operations on information. These algorithmic descriptions and representations are commonly used by those skilled in the data processing arts to convey the substance of their work effectively to others skilled in the art. These operations, while described functionally, computationally, or logically, are understood to be implemented by computer programs or equivalent electrical circuits, microcode, or the like. Furthermore, it has also proven convenient at times to refer to these arrangements of operations as modules, without loss of generality. The described operations and their associated modules may be embodied in software, firmware, hardware, or any combinations thereof. Certain steps, operations, or processes described herein may be performed or implemented with one or more hardware or software modules, alone or in combination with other devices. In some embodiments, a software module is implemented with a computer program product comprising a computer-readable medium containing computer program code, which can be executed by a computer processor for performing any or all steps, operations, or processes described. In some embodiments, systems comprise a computer and / or data storage provided virtually (e.g., as a cloud computing resource). In particular embodiments, the technology comprises use of cloud computing to provide a virtual computer system that comprises the components and / or performs the functions of a computer as described herein. Thus, in some embodiments, cloud computing provides infrastructure, applications, and software as described herein through a network and / or over the internet. In some embodiments, computing resources (e.g., data analysis, calculation, data storage, application programs, file storage, etc.) are remotely provided over a network (e.g., the internet; and / or a cellular network). ASTO-43522.601 Embodiments of the technology may also relate to an apparatus for performing the operations herein. This apparatus may be specially constructed for the required purposes (e.g., an application-specific integrated circuit or a field-programmable gate array) and / or it may comprise a general-purpose computing device (e.g., a microcontroller, microprocessor, and the like) selectively activated or reconfigured by a computer program stored in the computer. The apparatus may be configured to perform one or more steps, actions, and / or functions described herein, e.g., provided as instructions of a computer program. Such a computer program may be stored in a non- transitory, tangible computer readable storage medium or any type of media suitable for storing electronic instructions, which may be coupled to a computer system bus. Furthermore, any computing systems referred to in the specification may include a single processor or may be architectures employing multiple processor designs for increased computing capability. Additional embodiments will be apparent to persons skilled in the relevant art based on the teachings contained herein. BRIEF DESCRIPTION OF THE DRAWINGS The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee. These and other features, aspects, and advantages of the present technology will become better understood with regard to the following drawings. FIG. 1A is a schematic drawing of an embodiment of a QA device provided herein. FIG. 1B is a schematic drawing of the QA device of FIG.1A showing the orientation of the QA device relative to the beam direction for use in QA mode (e.g., to measure beam energy and range) and for use in high precision mode (e.g., to measure beam position, shape, and size). FIG. 1C shows use of a QA device in high precision mode. As shown in FIG. 1C, the beam is directed at the QA device from the left toward the posterior side of the QA device and irradiates the scintillator screen. Light produced by the scintillator screen is reflected by the mirrors to the camera. FIG. 1D shows use of a QA device in QA mode. As shown in FIG.1D, the beam is directed at the QA device from the right toward the anterior side of the QA device and passes through beam disrupting devices (e.g., wedges) prior to contacting the scintillator ASTO-43522.601 screen. Light produced by the scintillator screen is reflected by the mirrors to the camera. FIG. 2A shows a QA image (left) and a line profile (right) used for validation of beam energy. A measurement line was placed across a feature in the QA image and the beam intensity was plotted as a function of the distance along the measurement line. FIG. 2B shows a QA image (left) and a box profile (right) used for validation of beam energy. A measurement box was placed across the same feature in the QA image shown in FIG.2B and the beam intensity integrated across the height of the measurement box was plotted as a function of the distance along the width of the measurement box. FIG. 2C is a plot comparing the beam intensity from the measurement line of FIG. 2A and the measurement box of FIG.2B. FIG. 2D shows the QA image shown in FIG.2A and FIG.2B and a measurement of beam spot height and beam spot width. FIG. 3A shows an image acquired using the QA device of FIG. 1A for high- precision beam measurements as a result of a posterior beam exposure (e.g, from the left in FIG.1A). FIG. 3B shows a measurement of beam spot height and beam spot width for the image shown in FIG.3A. It is to be understood that the figures are not necessarily drawn to scale, nor are the objects in the figures necessarily drawn to scale in relationship to one another. The figures are depictions that are intended to bring clarity and understanding to various embodiments of apparatuses, systems, and methods disclosed herein. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. Moreover, it should be appreciated that the drawings are not intended to limit the scope of the present teachings in any way. DETAILED DESCRIPTION Provided herein is technology relating to quality assurance programs for external radiation therapy beam delivery systems and particularly, but not exclusively, to integrated devices and systems for daily quality assurance testing and validation of beam energy and range and for high precision measurements of beam position, shape, and size. In this detailed description of the various embodiments, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding ASTO-43522.601 of the embodiments disclosed. One skilled in the art will appreciate, however, that these various embodiments may be practiced with or without these specific details. In other instances, structures and devices are shown in block diagram form. Furthermore, one skilled in the art can readily appreciate that the specific sequences in which methods are presented and performed are illustrative and it is contemplated that the sequences can be varied and still remain within the spirit and scope of the various embodiments disclosed herein. All literature and similar materials cited in this application, including but not limited to, patents, patent applications, articles, books, treatises, and internet web pages are expressly incorporated by reference in their entirety for any purpose. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which the various embodiments described herein belongs. When definitions of terms in incorporated references appear to differ from the definitions provided in the present teachings, the definition provided in the present teachings shall control. The section headings used herein are for organizational purposes only and are not to be construed as limiting the described subject matter in any way. Definitions To facilitate an understanding of the present technology, a number of terms and phrases are defined below. Additional definitions are set forth throughout the detailed description. Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrase “in one embodiment” as used herein does not necessarily refer to the same embodiment, though it may. Furthermore, the phrase “in another embodiment” as used herein does not necessarily refer to a different embodiment, although it may. Thus, as described below, various embodiments of the invention may be readily combined, without departing from the scope or spirit of the invention. In addition, as used herein, the term “or” is an inclusive “or” operator and is equivalent to the term “and / or” unless the context clearly dictates otherwise. The term “based on” is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meaning of “a”, “an”, and “the” include plural references. The meaning of “in” includes “in” and “on.” ASTO-43522.601 As used herein, the terms “about”, “approximately”, “substantially”, and “significantly” are understood by persons of ordinary skill in the art and will vary to some extent on the context in which they are used. If there are uses of these terms that are not clear to persons of ordinary skill in the art given the context in which they are used, “about” and “approximately” mean plus or minus less than or equal to 10% of the particular term and “substantially” and “significantly” mean plus or minus greater than 10% of the particular term. As used herein, disclosure of ranges includes disclosure of all values and further divided ranges within the entire range, including endpoints and sub-ranges given for the ranges. As used herein, the disclosure of numeric ranges includes the endpoints and each intervening number therebetween with the same degree of precision. For example, for the range of 6–9, the numbers 7 and 8 are contemplated in addition to 6 and 9, and for the range 6.0–7.0, the numbers 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are explicitly contemplated. As used herein, the suffix “-free” refers to an embodiment of the technology that omits the feature of the base root of the word to which “-free” is appended. That is, the term “X-free” as used herein means “without X”, where X is a feature of the technology omitted in the “X-free” technology. For example, a “calcium-free” composition does not comprise calcium, a “mixing-free” method does not comprise a mixing step, etc. Although the terms “first”, “second”, “third”, etc. may be used herein to describe various steps, elements, compositions, components, regions, layers, and / or sections, these steps, elements, compositions, components, regions, layers, and / or sections should not be limited by these terms, unless otherwise indicated. These terms are used to distinguish one step, element, composition, component, region, layer, and / or section from another step, element, composition, component, region, layer, and / or section. Terms such as “first”, “second”, and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first step, element, composition, component, region, layer, or section discussed herein could be termed a second step, element, composition, component, region, layer, or section without departing from technology. As used herein, the word “presence” or “absence” (or, alternatively, “present” or “absent”) is used in a relative sense to describe the amount or level of a particular entity (e.g., component, action, element). For example, when an entity is said to be “present”, it means the level or amount of this entity is above a pre-determined threshold; conversely, when an entity is said to be “absent”, it means the level or amount of this ASTO-43522.601 entity is below a pre-determined threshold. The pre-determined threshold may be the threshold for detectability associated with the particular test used to detect the entity or any other threshold. When an entity is “detected” it is “present”; when an entity is “not detected” it is “absent”. As used herein, an “increase” or a “decrease” refers to a detectable (e.g., measured) positive or negative change, respectively, in the value of a variable relative to a previously measured value of the variable, relative to a pre-established value, and / or relative to a value of a standard control. An increase is a positive change preferably at least 10%, more preferably 50%, still more preferably 2-fold, even more preferably at least 5-fold, and most preferably at least 10-fold relative to the previously measured value of the variable, the pre-established value, and / or the value of a standard control. Similarly, a decrease is a negative change preferably at least 10%, more preferably 50%, still more preferably at least 80%, and most preferably at least 90% of the previously measured value of the variable, the pre-established value, and / or the value of a standard control. Other terms indicating quantitative changes or differences, such as “more” or “less,” are used herein in the same fashion as described above. As used herein, a “system” refers to a plurality of real and / or abstract components operating together for a common purpose. In some embodiments, a “system” is an integrated assemblage of hardware and / or software components. In some embodiments, each component of the system interacts with one or more other components and / or is related to one or more other components. In some embodiments, a system refers to a combination of components and software for controlling and directing methods. For example, a “system” or “subsystem” may comprise one or more of, or any combination of, the following: mechanical devices, hardware, components of hardware, circuits, circuitry, logic design, logical components, software, software modules, components of software or software modules, software procedures, software instructions, software routines, software objects, software functions, software classes, software programs, files containing software, etc., to perform a function of the system or subsystem. Thus, the methods and apparatus of the embodiments, or certain aspects or portions thereof, may take the form of program code (e.g., instructions) embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, flash memory, or any other machine-readable storage medium wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the embodiments. In the case of program code execution on programmable computers, the computing device generally includes a processor, a storage medium ASTO-43522.601 readable by the processor (e.g., volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device. One or more programs may implement or utilize the processes described in connection with the embodiments, e.g., through the use of an application programming interface (API), reusable controls, or the like. Such programs are preferably implemented in a high-level procedural or object-oriented programming language to communicate with a computer system. However, the program(s) can be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language, and combined with hardware implementations. As used herein, the term “structured to [verb]” means that the identified element or assembly has a structure that is shaped, sized, disposed, coupled, and / or configured to perform the identified verb. For example, a member that is “structured to move” is movably coupled to another element and includes elements that cause the member to move, or the member is otherwise configured to move in response to other elements or assemblies. As such, as used herein, “structured to [verb]” recites structure and not function. Further, as used herein, “structured to [verb]” means that the identified element or assembly is intended to, and is designed to, perform the identified verb. As used herein, the term “number” shall mean one or an integer greater than one (e.g., a plurality). As used herein, and when used in reference to communicating data or a signal, “in electronic communication” includes both hardline and wireless forms of communication. As used herein, “in electric communication” or “in electrical communication” means that a current passes, or can pass, between the identified elements. Being “in electric communication” is further dependent upon an element's position or configuration. For example, in a circuit breaker, a movable contact is “in electric communication” with the fixed contact when the contacts are in a closed position. The same movable contact is not “in electric communication” with the fixed contact when the contacts are in the open position. As used herein, the term “radiation source” or “source” refers to an apparatus that produces radiation (e.g., ionizing radiation) in the form of photons (e.g., x-rays) or particles (e.g., protons, neutrons, antiprotons, carbon ions, helium ions, neon ions, pions), e.g., a beam delivery system. In some embodiments, a radiation source comprises a linear accelerator (“linac”) that produces a beam of photons or electrons that finds use in treating a cancer patient by contacting a tumor with the photon or electron beam. In ASTO-43522.601 some embodiments, the source produces electromagnetic waves, e.g., in the form of x- rays or gamma rays having a wavelength in the range of approximately 1 pm to approximately 1 nm). While it is understood that radiation can be described as having both wave-like and particle-like aspects, it is sometimes convenient to refer to radiation in terms of waves and sometimes convenient to refer to radiation in terms of particles. Accordingly, both descriptions are used throughout without limiting the technology and with an understanding that the laws of quantum mechanics provide that every particle or quantum entity is described as either a particle or a wave. As used herein, the term “computed tomography” is abbreviated “CT” and refers both to tomographic and non-tomographic radiography. For instance, the term “CT” refers to numerous forms of CT, including but not limited to x-ray CT, positron emission tomography (PET), single-photon emission computed tomography (SPECT), and photon counting computed tomography. Generally, computed tomography (CT) comprises use of an opposed x-ray source and detector that revolve around a patient and subsequent reconstruction of images into different planes. In embodiments of CT (e.g., devices, apparatuses, and methods provided for CT) described herein, the x-ray source is a static source and the patient is rotated with respect to the static source. Currents for x-rays used in CT describe the current flow from a cathode to an anode and are typically measured in milliamperes (mA). As used herein, the term “beam” refers to a stream of radiation (e.g., electromagnetic wave and / or or particle radiation). In some embodiments, the beam is produced by a source and is restricted to a small-solid angle. In some embodiments, the beam is collimated. In some embodiments, the beam is generally unidirectional. In some embodiments, the beam is divergent. In some embodiments, the beam is a photon beam (e.g., an x-ray beam). In some embodiments, the beam is a particle beam (e.g., a proton beam). In some embodiments, the beam is a neutron, antiproton, hadron, carbon ion, helium ion, neon ion, or pion beam. As used herein, the term “radiolucent” refers to a material that is transparent to a radiotherapy beam, e.g., a material that does not inhibit or substantially inhibit the passage of a radiotherapy beam passing through the material. The term radiolucent may refer to a material that is transparent to a photon beam (e.g., an x-ray beam) or to a material that is transparent to a particle beam (e.g., a proton beam). As used herein, the term “patient” or “subject” refers to a mammalian animal that is identified and / or selected for imaging and / or treatment with radiation. Accordingly, in some embodiments, a patient or subject is contacted with a beam of ASTO-43522.601 radiation, e.g., a primary beam produced by a radiation source. In some embodiments, the patient or subject is a human. In some embodiments, the patient or subject is a veterinary or farm animal, a domestic animal or pet, or animal used for clinical research. In some embodiments, the subject or patient has a disease (e.g., a cancer) and / or the subject or patient has either been recognized as having or at risk of having a disease (e.g., a cancer). QA devices In some embodiments, the technology provides a quality assurance (QA) device. For instance, as shown in FIG. 1A, the technology provides a quality assurance device comprising a housing 110, a first mirror 121, a second mirror 122, a camera 130, a scintillator screen 140, and a number of (e.g., three) beam degrader wedges 150. In some embodiments, the QA device further comprises a parallel plate ion chamber 160. In some embodiments, the QA device further comprises a CT phantom 170. The housing comprises an anterior wall 111, a bottom 112, a posterior wall 113, a top 114, a first lateral wall 114, and a second lateral wall (not present in FIG.1A to show the internal components of the QA device). In some embodiments, the housing of the QA device comprises radiolucent materials. In some embodiments, the housing of the QA device consists or consists essentially of radiolucent materials. In some embodiments, the QA device does not comprise a metal or other high-Z material, e.g., the QA device does not comprise a material that causes CT artifacts, impacts CT image quality, or adversely affects Hounsfield units (HU) accuracy tests. Accordingly, in some embodiments, the QA device is high-Z-material-free. In some embodiments, the housing is sturdy, e.g., a force of approximately 5 Kg applied in any direction to the device does distort the device or deflect any surface of the device more than approximately 1 mm. Further, all components of the device are mounted rigidly within the housing, e.g., the alignment and respective positions of the components are maintained when the device is exposed to a moderate trauma, e.g., falling a distance of approximately 30 cm onto a hard surface. The housing 110 of the QA device is light-tight and thus minimizes and / or eliminates the entrance of external ambient light into the internal space of the device. The outside of the housing 110 comprises visible lines (e.g., approximately 1 mm wide) to indicate the center of the first mirror 121 and the scintillator screen 140 and to indicate the plane of the scintillator screen 140. In some embodiments, the visible lines ASTO-43522.601 are used to align the QA device to the beam using external lasers or other optical guidance systems. As shown in FIG.1A, the QA device comprises a camera 130. In some embodiments, e.g., as shown in FIG. 1A, the camera 130 is mounted to an internal surface of the anterior wall 111 of the housing 110. In some embodiments, the camera 130 is mounted to an internal surface of the anterior wall 111 of the housing near a corner where the anterior wall 111 of the housing 110 meets the bottom 112 of the housing 110. In some embodiments, the camera 130 is a high-resolution power-over- Ethernet (POE) camera. In some embodiments, the camera has an integration mode (e.g., “bulb mode”). In some embodiments, the QA device comprises a cable (e.g., an Ethernet cable) providing power to the camera 130 from an external power source and / or providing communication between the camera 130 and an external host computer. In some embodiments, the QA device comprises a cable connector (e.g., a 5- pin M12 connector) provided in the anterior wall 111, the bottom 112, the posterior wall 113, the top 114, the first lateral surface 114, or the second lateral surface, and the cable is connected to the cable connector. As shown in FIG.1A, the QA device comprises a scintillator screen 140 mounted on the internal surface of the posterior wall 113 of the housing 110. Accordingly, the scintillator screen 140 is positioned perpendicularly to the direction of the beam when the QA device is used in high precision mode as shown in FIG.1B or when the QA device is used in QA mode as shown in FIG. 1B. The scintillator screen 140 is positioned to produce light toward the first mirror 121 as described further below. In some embodiments, the scintillator screen has an active measurement area of approximately 20 cm by approximately 20 cm. As shown in FIG.1A, the QA device comprises a first mirror 121 at a 45-degree angle. The first mirror 121 comprises a radiolucent material (e.g., a plastic) so that a beam entering the QA device through the anterior wall 111 (e.g., when the QA device is used in QA mode) passes through the first mirror 121 to irradiate the scintillator screen 140. The mirror is provided with a first end at or near a corner where the top 114 of the housing 110 meets the posterior wall 113 of the housing 110 and a second end at or near the anterior wall 111 of the housing 110. Accordingly, as shown in FIG.1B, the first mirror 121 is provided at an angle of 45 degrees with respect to the scintillator screen 140 and thus the first mirror 121 reflects light produced by the scintillator screen 140 toward the second mirror 122 and camera 130. Thus, the beam passes through the first mirror 121 and the light produced by the scintillator screen 140 is reflected by the first ASTO-43522.601 mirror 121. In some embodiments, the QA device comprises a first mirror support 180 upon which is mounted the first mirror 121. As shown in FIG.1A, the QA device comprise a second mirror 122 at a 45-degree angle. Accordingly, the second mirror 122 and the first mirror 121 are parallel. As shown in FIG.1A and FIG. 1B, the scintillator screen 140, the first mirror 121, the second mirror 122, and the camera are arranged so that light produced by the scintillator screen 140 is directed by the first mirror 121 and the second mirror 122 toward the camera 130. In some embodiments, the camera 130 comprises a lens (e.g., a 12-mm lens) that allows the camera 130 to image the entire scintillator screen 140 in the field of view of the camera 130. In some embodiments, the camera integrates the scintillation light produced by the scintillation screen 140 for up to approximately 10 minutes. As shown in FIG.1A and FIG. 1B, the QA device comprises a number of beam degrader wedges 150. In an exemplary embodiment, the QA device comprises three beam degrader wedges, e.g., three 50-mm-thick, 45-degree angle beam degrader wedges made of polyethylene. As described herein, the beam degrader wedges 150 find use when the QA device is used in QA mode to verify the energy related parameters of the beam, e.g., beam energy and range. In some embodiments, wedge 1 is provided for high energy measurements and has a side length of approximately 24 cm; wedge 2 is provided for medium energy measurements and has a side length of approximately 18 cm; and wedge 3 is provided for low energy measurements and has a side length of approximately 10 cm. In some embodiments, the QA device comprises a CT phantom. In some embodiments, the QA device comprises a CT phantom 170 on an external surface, e.g., on the top 114 of the housing 110. In some embodiments, the QA device comprises a CT phantom in the internal space of the device. In some embodiments, the CT phantom comprises a number of precisely machined plastic CT QA disks (e.g., a first disk having a 10-cm diameter and, optionally, a second disk having a 20-cm diameter) and the CT QA disks comprise CT contrast features, e.g., embedded within the plastic disks. In some embodiments, the CT QA disks are mounted on the top 114 of the QA device, e.g., as shown in FIG.1A. In some embodiments, e.g., as shown in FIG.1A, the QA device comprises an ionization chamber 160, e.g., a parallel plate ion chamber. In some embodiments, the QA device comprises a triax low-noise cable connector to operate the ionization chamber. ASTO-43522.601 In some embodiments, the QA device comprises an indicator that produces light when the QA device is supplied with power. In some embodiments, the total mass of the device is less than 15 Kg. In some embodiments, the device (e.g., the housing) is no larger than approximately 50 cm (height) × 28 cm × 31 cm. Accordingly, the QA device provides a technology that can be irradiated by a beam from two directions. When irradiated from a first direction, the QA device provides high precision size, shape, and position measurements of a minimally perturbed beam. When irradiated from a second direction, the QA device provides QA measurements of a beam passing through certain objects to perturb the beam, e.g., a set of plastic wedges to measure beam energy and range. The scintillation light is produced when any radiation beam irradiates the scintillator screen and is reflected to the camera by the two 45- degree mounted mirrors. Use of QA devices The QA device finds use in quality assurance testing and validation of beam energy and range and for high precision measurements of beam position, shape, and size. The integrated QA devices and systems also find use in quality assurance testing and validation of daily patient set up using high-resolution diagnostic imaging provided by the CT scanner and optical surface guidance systems for image guided radiation therapy. The QA devices and systems described herein find use in calibrating beam delivery, performing acceptance testing, and commissioning of beam delivery systems. In some embodiments, the QA device is configured to be positioned on a patient support system, e.g., as described in U.S. Pat. No.11,529,109 (entitled “Patient Positioning Apparatus”), in U.S. Pat. App. Pub. No.20230172566 (entitled “Patient Positioning System”), or in Int’l Pat. App. Pub. No. WO 2024 / 151806 (entitled “Patient Immobilization”), each of which is incorporated herein by reference. For instance, in some embodiments, the QA device is configured to be placed on a seat member of a patient support and contact a back rest of the patient support. In particular, e.g., as shown in FIG. 1C and FIG.1D, the QA device may be used in a high precision mode and in a QA mode. FIG.1C shows use of the QA device in a high precision mode for high precision measurements appropriate for beam calibration procedures, acceptance testing, and commissioning measurements. As shown in FIG. 1C, the beam enters the QA device through a thin light tight entrance window provided in the posterior side to minimize scattering of the beam by the entrance window that ASTO-43522.601 would increase the spot size of the beam. FIG.1D shows use of the QA device in a QA mode for regular (e.g., daily, weekly, monthly, yearly) QA testing. As shown in FIG.1D, the beam enters the QA device through a light tight window provided in the anterior side and passes through a number of plastic beam-disrupting wedges of different sizes to measure beam energies in three test energies or test energy ranges. The test energies are selected such that the beam does not pass through the thicker portion of each wedge and thus beam thus stops within wedge. The scintillation light emitted from the scintillator screen beyond the wedges is captured by the camera. Plotting the light intensity resembles the Bragg peak. See, e.g., FIG. 2A, FIG.2B, and FIG.2C. In some embodiments, the QA device comprises a parallel plate ionization chamber to provide an accurate measure of the total imparted energy in QA mode. In some embodiments, the beam for QA testing with the QA device is configured using a treatment planning system. In some embodiments, a CT scan of the device is imported into the treatment planning system. In some embodiments, the QA device measures beam spot position in two dimensions (e.g., X and Y) that are normal to the direction of beam propagation (e.g., Z). In some embodiments, the QA device measures beam spot position in two dimensions (e.g., X and Y) with a tolerance of 0.1 mm in each dimension. In some embodiments, methods comprise determining the centroid of a gaussian fit to the beam spot profile in the X and Y directions. In some embodiments, the QA device measures beam spot size in air (e.g., sigma X and sigma Y). In some embodiments, the QA device measures beam spot size in air (e.g., sigma X and sigma Y) with a tolerance of 0.1 mm in each dimension. with a tolerance of 0.1 mm. In some embodiments, methods comprise determining the sigma of the gaussian fit to the beam spot profile in the X and Y directions. In some embodiments, the QA device measures a beam energy. In some embodiments, the QA device measures a monitor unit (MU) linearity. In some embodiments, the QA device measures a monitor unit (MU) linearity with a tolerance of ± 0.5%. In some embodiments, methods comprise measuring the illuminance from each beam spot. In some embodiments, the QA device measures dose uniformity. In some embodiments, the QA device measures dose uniformity with a tolerance of ± 2%. In some embodiments, methods comprise performing trend analysis by comparing the daily beam parameters to baseline values or an average of multiple values acquired for a period of time (e.g., days, weeks, years). ASTO-43522.601 In some embodiments, the QA device is used to test and validate image guided radiotherapy positioning. In some embodiments, the QA device is used to test and validate image guided radiotherapy positioning with a tolerance of ± 0.25 mm. In some embodiments, methods comprise obtaining a CT scan of the QA device and using an image guided radiotherapy system to position the QA device in the beam. In some embodiments, the QA device is used to test optical positioning. In some embodiments, the QA device is used to test optical positioning with a tolerance of ± 0.50 mm. In some embodiments, methods comprise using an optical guidance system to position the QA device in the beam. In some embodiments, the QA device is used to test laser alignment. In some embodiments, the QA device is used to test laser alignment with a tolerance of ± 0.5 mm. In some embodiments, methods comprise using the device to verify treatment room lasers with respect to lines provided on the QA device when the QA device has been positioned. In some embodiments, the QA device is configured to be positioned and / or set up in less than 2 minutes. In some embodiments, methods comprise positioning the QA device on a patient positioning system. In some embodiments, the beam is delivered in a time that is less than 30 seconds. In some embodiments, the analysis of data acquired from the QA device is completed in a time that is less than 30 seconds. QA systems The technology provides embodiments of QA systems. For example, in some embodiments, the technology provides a system comprising a QA device as described herein, a computer, and computer software (e.g., control software). In some embodiments, the control software comprises a “QA” mode (e.g., for measuring beam energy and range) and a “Precision Beam Data Acquisition” mode (e.g., for measuring beam position, size, and shape). In some embodiments, the QA device is connected to the computer by a cable. In some embodiments, the cable provides communication between the QA device (e.g., the camera of the QA device) and / or provides power to the QA device (e.g., to the camera and / or scintillation screen). In some embodiments, the cable is an Ethernet cable (e.g., a CAT 5 or CAT 6 Ethernet cable). In some embodiments, the external host computer is configured to control the QA device and to acquire data from the device using control software. The control software connects automatically to the camera on powerup of the system. In addition, the control software provides a user interface for a user to operate the system. The control software ASTO-43522.601 provides a “QA” mode and a “Precision Beam Data Acquisition” mode. The control software is configured to control the camera iris opening or to control the amplification of the signal from the camera sensor (“gain”). The control software is configured to start and / or stop a measurement. For example, the control software is configured to perform one or more functions including acquiring an image (e.g., a background image, a reference image, and / or a test image) from the camera; selecting a working directory (e.g., according to user input); and saving the image (e.g., the background image, the reference image, and / or the test image) to the working directory. The control software may be configured to acquire a background image for a selectable time. The control software is configured to apply a lens distortion correction to an image (e.g., a background image, a reference image, and / or a test image). The control software is configured to subtract a background image from a test image or from a reference image. The control software is configured to denoise an image (e.g., with a 5- pixel median filter). The control software is configured to apply a pixel and / or mm correction to the pixel values of an image to provide accurate distance measurements at the plane of the scintillator screen, and / or save all the calculated metrics characterizing an image in a text or comma-separated value format. The QA Mode of operation of the control software is configured to compare a test image with a reference image, e.g., by displaying a visual overlay of the test image and the reference image, calculating a translational offset of the test image relative to the reference image, calculating a rotational offset of the test image relative to the reference image, calculating a magnification difference (e.g., a dilation) of the test image relative to the reference image, and displaying the translational offset (e.g., in mm), the rotational offset (e.g., in degrees), and / or the magnification difference (e.g., as a scale factor or an estimated difference in the distance from the beam source point for the test image and the reference image). The QA Mode of operation of the control software is further configured to find the centroids, horizontal widths, and vertical widths (e.g., within one sigma (e.g., within 66.7%) of the maximum intensity) of beam spots in a predetermined beam spot region of a test image or of a reference image; compare the beam spot centroids, horizontal widths, and vertical widths of the test image beam spots with the beam spot centroids, horizontal widths, and vertical widths of the reference image beam spots; identify (e.g., color code) differences between the beam spot centroids, horizontal widths, and vertical widths of the test image and the beam spot centroids, horizontal widths, and vertical ASTO-43522.601 widths of the reference image that are larger than set comparison tolerances for beam spot centroids, horizontal widths, and vertical widths; and compare the average intensity values and the peak intensity values for each test image beam spot with the average intensity values and the peak intensity values for each corresponding beam spot in the reference image. The QA Mode of operation of the control software is further configured to determine test Bragg peak curves from intensities measured for a beam after having passed through the plastic wedges; compare the test Bragg peak curves with the corresponding reference Bragg peak curves determined previously from a reference image; calculate differences (e.g., in mm) at the 50% level for the test Bragg peak curves and the reference Bragg peak curves in the distal regions; compare the positions of peaks in the test Bragg peak curves and the reference Bragg peak curves; and identify (e.g., color code) differences between the test Bragg peak curves and the reference Bragg peak curves that are larger than set comparison tolerances for Bragg peak curves. The user interface provides a configuration tab to enter and adjust comparison tolerances for beam spot centroids, horizontal widths, and vertical widths; and for Bragg peak curves. The Precision Beam Data Acquisition Mode of operation of the control software is configured to acquire an image from the camera; select a directory; and save the image (e.g., with a user-input name) to the directory. The Precision Beam data Acquisition Mode of operation of the control software may also provide as option to find the centroids, horizontal widths, and vertical widths (e.g., within one sigma (e.g., within 66.7%) of the maximum intensity) of beam spots in the image. Although the disclosure herein refers to certain illustrated embodiments, it is to be understood that these embodiments are presented by way of example and not by way of limitation. Examples Example 1 – design and construction of a QA device and system During the development of embodiments of the technology described herein, a quality assurance (QA) device was designed and constructed essentially according to the drawing shown in FIG.1A. The QA device comprised a housing in which were mounted a scintillator screen, a first mirror, a second mirror, and plastic beam degrader wedges arranged as shown in FIG.1A. ASTO-43522.601 Further, during the development of embodiments of the technology described herein, a system comprising the QA device, an external host computer, and a control software was constructed and tested. The system comprised the QA device connected by an Ethernet cable to the external host computer on which was installed operating system software (e.g., MICROSOFT WINDOWS 10) and a control software. The housing of the QA device was made from radiolucent materials. Further, the QA device comprised no metal or other high-Z material, e.g., that could cause CT artifacts, impact CT image quality, or adversely affect Hounsfield units (HU) accuracy tests. Accordingly, the QA device was high-Z-material-free. The housing dimensions were 26 cm × 31 cm × 46 cm. The housing was sturdy such that a force of 5 Kg applied in any direction to the device did not distort the device or deflect any surface of the device more than 1 mm. Further, all components of the device were mounted rigidly within the housing such that the alignment and respective positions of the components are maintained should the device be exposed to a moderate trauma, e.g., falling a distance of approximately 30 cm onto a hard surface. The housing of the device is light-tight. The outside of the housing was marked with visible lines (e.g., 1 mm wide) to indicate the center of the mirror and the scintillator screen and to indicate the plane of the scintillator screen. The visible lines are used to align the device to the beam using external lasers or other optical guidance systems. The scintillator screen was a Kodak Lanex Regular Screen having a size of 21 × 21 cm2, and the scintillator screen was mounted perpendicular to the beam direction when the QA device is in use. As described herein, the scintillator screen may be irradiated by radiation from two opposed directions that are essentially normal to the scintillator screen surface. The camera was a high-resolution power-over-Ethernet (POE) camera having an integration mode (e.g., “bulb mode”). A 12-mm lens was mounted on the camera to image the entire scintillator screen in the field of view. The camera was able to integrate the scintillation light for up to 10 minutes. The first radiolucent mirror was mounted at 45 degrees to the beam direction and was arranged to deflect the scintillator light produced by the scintillator screen to the camera. The second mirror was arranged to deflect the light through 90 degrees to shorten the total height of the device. The QA device comprised three 50-mm-thick, 45- degree angle beam degrader wedges made of polyethylene for verifying the energy related parameters of the beam. Wedge 1 for high energy measurements had a side ASTO-43522.601 length of 24 cm; wedge 2 for medium energy measurements had a side length of 18 cm; and wedge 3 for low energy measurements had a side length of 10 cm. The device comprised a single CAT 6 cable connector (e.g., a 5-pin M12 connector) to which a cable was connected to connect the camera to the external host computer. The cable connector may be located at any location on the housing, e.g., on one of the sides near the bottom. The device may be adapted to accommodate a triax low-noise cable connector to operate an ionization chamber mounted in the beam. The device was powered by 24 volts of direct current (± 5%) at a maximum power of 20 watts. The device included an indicator light (e.g., a light emitting diode) that produced a green light when the device was supplied with power. The device may comprise a computerized tomography (CT) QA phantom on the top surface of the device or, alternatively, a CT QA phantom may be housed within the device. The total mass of the device was less than 15 Kg. The external host computer was configured to control the device and acquire data from the device using control software and a user interface to operate the system. The control software provided a “QA” mode and a “Precision Beam Data Acquisition” mode. Example 2 – Data provided by the QA device and system During the development of embodiments of the technology provided herein, the QA device and system of Example 1 were used to acquire QA data. First, the QA device was used in QA mode to measure beam characteristics. Three monoenergetic planar proton beams (low, middle, and high energy) were directed toward the anterior side of the QA device. The three monoenergetic planar proton beams passed through the three plastic wedges prior to irradiating the scintillator screen. In addition, spot beams of varying energies were directed toward the anterior side of the QA device. The spot beams were unperturbed by the QA device prior to irradiating the scintillator screen. The light produced by the scintillator screen was reflected by the mirrors and recorded by the camera. FIG. 2A and FIG.2B show scintillation light produced by the monoenergetic planar proton beams after passing through the plastic wedges and by the unperturbed spot beams. The longitudinal patterns were produced by the three monoenergetic planar proton beams (top, medium energy beam; middle, high energy beam; bottom, low energy beam) directed at the three plastic wedges, respectively. The circular spots were produced by the unperturbed spot beams directed at the scintillator screen. Each beam spot had a different energy. ASTO-43522.601 The longitudinal patterns were analyzed by measuring the pixel intensities along a line (FIG. 2A) or integrated within a measurement box (FIG. 2B). Data produced from the single-line profile and integrated measurements resemble the proton Bragg peak. The single line profile had a less defined peak (FIG.2A) because the protons scatter out of the beam as the beam energy decreases when degraded by the increasing thicknesses of the wedges. When the data are integrated over the entire intensity profile (FIG.2B), then all scattered protons are measured and a more pronounced peak is observed. The two measured curves are compared in FIG. 2C, which shows that both data analysis methods produce a similar distal edge beam profile. The distal edge beam profile is used in QA validation to identify relevant changes in the beam energy. The size of a spot produced by a spot beam increases as a function of decreasing beam energy. Accordingly, the data collected by the QA device were used to verify that the beam tune (i.e., the spot focus) was correct for each beam energy by measuring the sizes and shapes of the spots produced by each spot beam. The position of each spot beam (i.e., as produced by the scanning magnets) was verified by calculating a centroid of each spot on the scintillator screen and thus measure each beam spot position in the beam coordinate system. The spot size and position analyses are shown in FIG.2D. Second, the QA device was used in high precision mode to measure beam spot position and beam spot size. Twenty-five beams were produced on a 20 cm × 20 cm grid using the same beam energy for each beam. The beams were directed toward the posterior side of the QA device and irradiated the scintillator screen. The light produced by the scintillator screen was reflected by the mirrors and recorded by the camera. FIG. 3A shows the scintillation light produced by the scintillator screen. The spot size and spot position were measured for each beam spot using the QA system software. See FIG. 3B. The spot sizes and spot positions were used to verify that all beam spots had the correct shape (i.e., circular or elliptical), had an equal size, and were equidistant from each other. All publications and patents mentioned in the above specification are herein incorporated by reference in their entirety for all purposes. Various modifications and variations of the described compositions, methods, and uses of the technology will be apparent to those skilled in the art without departing from the scope and spirit of the technology as described. Although the technology has been described in connection with specific exemplary embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various ASTO-43522.601 modifications of the described modes for carrying out the invention that are obvious to those skilled in the art are intended to be within the scope of the following claims.

Claims

ASTO-43522.601 CLAIMS WE CLAIM:

1. A quality assurance (QA) device comprising: a housing comprising a posterior side and an anterior side; a scintillator screen; a number of beam degrader wedges; a first mirror that is radiolucent; a second mirror; and a camera.

2. The QA device of claim 1, wherein the first mirror comprises a plastic.

3. The QA device of claim 1, wherein the housing comprises radiolucent materials.

4. The QA device of claim 1, wherein the housing is light-tight.

5. The QA device of claim 1, wherein the QA device has a mass of less than 15 Kg.

6. The QA device of claim 1, wherein the scintillator screen is mounted on an internal surface of the posterior side of the housing; the first mirror is oriented to reflect light produced by the scintillator screen toward the second mirror; and the second mirror is oriented to reflect light produced by the scintillator screen and reflected by the first mirror toward the camera.

7. The QA device of claim 1, wherein the first mirror is oriented at a 45-degree angle with respect to the scintillator screen.

8. The QA device of claim 1, further comprising a computerized tomography phantom.

9. The QA device of claim 1, further comprising an ion chamber.ASTO-43522.601 10. The QA device of claim 1, further comprising visible lines on an external surface of the housing, said visible lines marking the center of the radiolucent mirror, the scintillator screen, and / or the plane of the scintillator screen.

11. The QA device of claim 1, wherein the camera is a high-resolution power-over- Ethernet camera.

12. The QA device of claim 1, wherein the scintillator screen has an active measurement area of approximately 20 cm × 20 cm.

13. The QA device of claim 1, wherein the beam degrader wedges are made from polyethylene.

14. The QA device of claim 1, comprising three beam degrader wedges.

15. The QA device of claim 1, wherein the first mirror reflects visible light and transmits a high-energy radiation beam.

16. The QA device of claim 15, wherein the high-energy radiation beam comprises x- rays or hadrons.

17. A method of performing quality assurance for a radiotherapy system, said method comprising: providing a quality assurance (QA) device comprising: a housing comprising a posterior side and an anterior side; a scintillator screen; a number of beam degrader wedges; a first mirror that is radiolucent; a second mirror; and a camera; contacting the posterior side of the QA device to provide high precision measurements of beam position, shape, and / or size; and contacting the anterior side of the QA device to provide periodic measurements of beam energy and / or range.ASTO-43522.601 18. The method of claim 17, wherein said periodic measurements are for daily QA testing.

19. The method of claim 17, wherein said periodic measurements are for weekly QA testing, monthly QA testing, or yearly QA testing.

20. The method of claim 17, wherein said high precision measurements are for calibrating beam delivery, performing acceptance testing, and / or commissioning of a beam delivery system.

21. The method of claim 17, wherein said QA device further comprises a computerized tomography phantom.

22. The method of claim 21, wherein the method further comprises performing QA testing of a computerized tomography scanner.

23. The method of claim 21, further comprising testing image guided radiotherapy positioning.

24. The method of claim 21, further comprising positioning the QA device using or a radiation-based image guidance system.

25. The method of claim 17, further comprising testing an optical guidance system.

26. The method of claim 17, further comprising validating a patient set-up system.

27. The method of claim 17, further comprising placing the QA device on a patient positioning system.

28. The method of claim 17, further comprising testing laser alignment.

29. A method of performing quality assurance for a radiotherapy system, said method comprising: providing a quality assurance (QA) device comprising: a housing comprising a posterior side and an anterior side;ASTO-43522.601 a scintillator screen; a number of beam degrader wedges; a first mirror that is radiolucent; a second mirror; and a camera; and one or more of: measuring a beam spot size in two dimensions; measuring a beam spot position in two dimensions; measuring the beam spot in air in two dimensions; measuring a beam energy; measuring a monitor unit linearity; measuring an illuminance of a beam spot; measuring a dose uniformity; and / or comparing a test beam parameter value to a baseline beam parameter value or an average of multiple beam parament values acquired over a period of days, weeks, or months.

30. A quality assurance (QA) system comprising: a quality assurance device comprising: a housing comprising a posterior side and an anterior side; a scintillator screen; a number of beam degrader wedges; a first mirror that is radiolucent; a second mirror; and a camera; and a computer.

31. The QA system of claim 30, further comprising a computer-readable medium containing computer program code for controlling the system in a QA mode or a precision mode.

32. The QA system of claim 30, further comprising a computer-readable medium containing computer program code for acquiring an image from the camera; applying a lens distortion correction to the image; denoising the image; subtracting a background from the image; and applying a pixel correction to the image.ASTO-43522.601 33. The QA system of claim 31, wherein the computer program code for controlling the system in a QA mode is configured to compare a test image with a reference image; find a centroid, horizontal width, and / or vertical width of a beam spot; and determine a test Bragg peak curve from intensities measured for a beam.

34. The QA system of claim 31, wherein the computer program code for controlling the system in precision mode is configured to acquire an image from the camera; and find a centroid, horizontal width, and / or vertical width of a beam spot in the image.

35. The QA system of claim 30, further comprising a computer-readable medium comprising computer program code for a user interface to control the system and / or to accept comparison tolerances for beam spot centroids, horizontal widths, and vertical widths; and for Bragg peak curves.

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