Multiphase Computed Tomography Scanning for Improved Workflow and Performance

Abstract

An x-ray imaging apparatus and related method are provided to perform multi-pass imaging scans to improve quality and workflow. The imaging scan can be segmented into multiple passes that are faster than a full imaging scan. Data received from an initial scan pass can be utilized early in the workflow and have sufficient quality for treatment setup, including when data required to perform another scan pass to generate a higher quality image is needed, which may be required for treatment planning. In one embodiment, data acquisition and reconstruction techniques are used when the detector is offset in channels and / or axially during multi-pass for a large FOV.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of eleven U.S. Provisional Patent Applications, including: Application No. 62 / 773,712, filed on November 30, 2018 (Attorney Docket No. 38935 / 04001); Application No. 62 / 773,700, filed on November 30, 2018 (Attorney Docket No. 38935 / 04002); Application No. 62 / 796,831, filed on January 25, 2019 (Attorney Docket No. 38935 / 04004); Application No. 62 / 800,287, filed on February 1, 2019 (Attorney Docket No. 38935 / 04003); Application No. 62 / 801,260, filed on February 5, 2019 (Attorney Docket No. 38935 / 04006); Application No. 62 / 813,335, filed on March 4, 2019 (Attorney Docket No. 38935 / 04007); Application No. 62 / 821,116, filed on March 20, 2019 (Attorney Docket No. 38935 / 04009); Application No. 62 / 836,357, filed on April 19, 2019 (Attorney Docket No. 38935 / 04016); Application No. 62 / 836,352, filed on April 19, 2019 (Attorney Docket No. 38935 / 04017); Application No. 62 / 843,796, filed on May 6, 2019 (Attorney Docket No. 38935 / 04005); and Application No. 62 / 878,364, filed on July 25, 2019 (Attorney Docket No. 38935 / 04008). This application also relates to ten non-provisional U.S. Patent Applications filed on the same day, including: Attorney Docket No. 38935 / 04019, an application entitled "MULTIMODAL RADIATION APPARATUS AND METHODS"; Attorney Docket No. 38935 / 04020, an application entitled "APPARATUS AND METHODS FOR SCALABLE FIELD OF VIEW IMAGING USING A MULTI-SOURCE SYSTEM"; Attorney Docket No. 38935 / 04011, an application entitled "INTEGRATED HELICAL FAN-BEAM COMPUTED TOMOGRAPHY IN IMAGE-GUIDED RADIATION TREATMENT DEVICE"; Attorney Docket No. 38935 / 04010, an application entitled "COMPUTED TOMOGRAPHY SYSTEM AND METHOD FOR IMAGE IMPROVEMENT USING PRIOR IMAGE";Application with Attorney Docket No. 38935 / 04013, entitled "OPTIMIZED SCANNING METHODS AND TOMOGRAPHY SYSTEM USING REGION OF INTEREST DATA"; Application with Attorney Docket No. 38935 / 04015, entitled "HELICAL CONE-BEAM COMPUTED TOMOGRAPHY IMAGING WITH AN OFF-CENTERED DETECTOR"; Application with Attorney Docket No. 38935 / 04012, entitled "METHOD AND APPARATUS FOR SCATTER ESTIMATION IN CONE-BEAM COMPUTED TOMOGRAPHY"; Application with Attorney Docket No. 38935 / 04014, entitled "ASYMMETRIC SCATTER FITTING FOR OPTIMAL PANEL READOUT IN CONE-BEAM COMPUTED TOMOGRAPHY"; Application with Attorney Docket No. 38935 / 04018, entitled "METHOD AND APPARATUS FOR IMPROVING SCATTER ESTIMATION AND CORRECTION IN IMAGING"; and Application with Attorney Docket No. 38935 / 04022, entitled "METHOD AND APPARATUS FOR IMAGE RECONSTRUCTION AND CORRECTION USING INTER-FRACTIONAL INFORMATION". The content of all of the above (one or more) patent applications and (one or more) patents are hereby incorporated by reference in their entirety.; TECHNICAL FIELD

[0003] Aspects of the disclosed technology relate to computed tomography imaging and, more particularly, to apparatus and methods for multi-pass scanning associated with imaging, data reconstruction, and workflows, including when using an off-centered (offset) detector during helical cone-beam computed tomography scanning. BACKGROUND OF THE INVENTION

[0004] Computed tomography (CT) imaging, including cone beam computed tomography (CBCT), is a valuable tool in radiation diagnosis and treatment. It can be used for patient positioning and dose calculation. It also has the potential to allow doctors to perform adaptive radiation therapy, including in the context of image-guided radiation therapy (IGRT). IGRT can utilize medical imaging techniques such as CT to collect images of a patient before, during, and / or after treatment.

[0005] A popular form of data acquisition is circular scanning, where a central detector is used for scanning small objects (e.g., the head), and detectors that are off-center (offset or shifted) in the channel direction are used for scanning large objects (e.g., the abdomen). For most radiation therapy systems, circular scanning may be the only practical option because the gantry can only rotate a limited number of degrees in one direction, preventing these machines from using a helical source trajectory. Compared to circular scanning, helical scanning can provide higher quality images with fewer artifacts, reduced scatter, and faster scans, but the view completion is much more complex.

[0006] CT images acquired on an IGRT system have two main applications: (a) registration with planning CT images for patient treatment setup; and (b) adaptive planning and dose calculation. The requirements for CT images for the two applications can be different. For registration and treatment setup, absolute accuracy in CT quantification (e.g., CT numbers) is not as critical as in adaptive planning and dose calculation, yet a relatively large axial field of view (FOV) is allowed for registration and setup accuracy. Summary of the Invention

[0007] In one embodiment, a method of collecting imaging data during a multi-pass scan includes: moving a patient support relative to a rotatable gantry system during a first pass of an imaging scan, wherein a first radiation source and a radiation detector are coupled to the rotatable gantry system positioned at least partially around the patient support; receiving first projection data measured by the radiation detector during the first pass; moving the patient support relative to the rotatable gantry system during a second pass of the imaging scan; receiving second projection data measured by the radiation detector during the second pass; and reconstructing a patient image based on the first projection data and the second projection data.

[0008] Features described and / or illustrated with respect to one embodiment can be used in the same way or in a similar way for one or more other embodiments and / or combined with the features of other embodiments or replace the features of other embodiments.

[0009] The description of the present invention does not limit in any way the words used in the claims or the scope of the claims or the invention. The words used in the claims have their full ordinary meaning. Brief Description of the Drawings

[0010] In the drawings that are incorporated in and form a part of the specification, embodiments of the invention are shown, which, together with the general description of the invention given above and the detailed description given below, serve to illustrate embodiments of the invention. It will be understood that the element boundaries shown in the drawings (e.g., boxes, groups of boxes, or other shapes) represent one embodiment of the boundaries. In some embodiments, one element may be designed as multiple elements, or multiple elements may be designed as one element. In some embodiments, an element shown as an internal component of another element may be implemented as an external component, and vice versa. Additionally, the elements may not be drawn to scale.

[0011] Figure 1 is a perspective view of an exemplary x-ray imaging device according to one aspect of the disclosed technology;

[0012] Figure 2 is a schematic diagram showing an x-ray imaging device integrated in an exemplary radiological diagnostic and treatment device according to one aspect of the disclosed technology;

[0013] Figure 3 is a diagram of an exemplary x-ray imaging device shown in a defined world coordinate system.

[0014] Figure 4 is a diagram of an exemplary x-ray imaging device showing the patient support moving into the gantry during one scan pass.

[0015] Figure 5 is a diagram of an exemplary x-ray imaging device showing the patient support moving out of the gantry during another scan pass.

[0016] Figure 6 is a diagram of an exemplary trajectory associated with two interleaved scans during a dual-pass helical scan protocol with a large pitch for rapid scanning.

[0017] Figure 7 is a diagram of the 3D geometry of an exemplary data acquisition system.

[0018] Figure 8 is a diagram of the geometry of the data acquisition system in an exemplary (x, z) plane.

[0019] Figure 9A is a diagram of an exemplary scan trajectory and offset detector positions during a left-handed helix.

[0020] Figure 9B is a diagram of an exemplary scan trajectory and offset detector positions during a right-handed helix.

[0021] Figure 10 is in an exemplary transverse plane at Figure 9A and9B Illustration of data availability during the scan shown.

[0022] Figure 11 Shows the use of Figure 9A and 9B Exemplary reconstruction of a thoracic phantom scanned as shown.

[0023] Figure 12 Is a flowchart of an exemplary multi-pass imaging process.

[0024] Figure 13 Is a flowchart of another exemplary multi-pass imaging process.

[0025] Figure 14 Is a flowchart of another exemplary multi-pass imaging process.

[0026] Figure 15 Is a flowchart of another exemplary multi-pass imaging process.

[0027] Figure 16 Is a flowchart depicting an exemplary method of IGRT using a radiation therapy device.

[0028] Figure 17 Is a block diagram depicting an exemplary image-based pre-delivery step.

[0029] Figure 18 Is a block diagram depicting exemplary data sources that can be utilized during an imaging or image-based pre-delivery step. Detailed Description

[0030] The following includes definitions of exemplary terms that can be used throughout the disclosure. The singular and plural forms of all terms fall within each meaning.

[0031] As used herein, a "component" can be defined as a part of hardware, a part of software, or a combination thereof. A part of hardware can include at least a processor and a part of a memory, where the memory includes instructions to be executed. A component can be associated with a device.

[0032] As used herein, "logic" is synonymous with "circuitry" and includes, but is not limited to, hardware, firmware, software, and / or any combination of each that performs one or more functions or actions. For example, depending on the desired application or need, logic can include a software-controlled microprocessor, discrete logic such as an application specific integrated circuit (ASIC), or other programmed logic devices and / or controllers. Logic can also be embodied entirely as software.

[0033] As used herein, "processor" includes, but is not limited to, one or more of any number of processor systems or stand-alone processors, such as any combination of microprocessors, microcontrollers, central processing units (CPUs), and digital signal processors (DSPs). The processor may be associated with various other circuits that support the operation of the processor, such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), clock, decoder, memory controller, or interrupt controller, etc. These support circuits may be internal or external to the processor or its associated electronic package. The support circuits communicate operatively with the processor. The support circuits are not necessarily shown separately from the processor in a block diagram or other figure.

[0034] As used herein, "signal" includes, but is not limited to, one or more electrical signals, including analog or digital signals, one or more computer instructions, bits, or bitstreams, etc.

[0035] As used herein, "software" includes, but is not limited to, one or more computer-readable and / or executable instructions that cause a computer, processor, logic, and / or other electronic device to perform functions, actions, and / or behaviors in a desired manner. The instructions may be embodied in various forms, such as routines, algorithms, modules, or programs that include separate applications or code from dynamically linked sources or libraries.

[0036] Although the above exemplary definitions have been provided, it is the applicant's intention that the broadest reasonable interpretation consistent with this specification be used for these and other terms.

[0037] As discussed in more detail below, embodiments of the disclosed technology relate to a multi-pass scan for improved workflow and / or performance. In some embodiments, a radiation therapy delivery device and method may utilize an integrated low-energy radiation source for CT, for use in combination with or as part of IGRT. In particular, for example, a radiation therapy delivery device and method may combine a low-energy collimated radiation source for imaging in a gantry using rotational image acquisition with a high-energy radiation source for therapeutic treatment. In various embodiments, a low-energy radiation source (e.g., kV) may produce higher quality images compared to imaging via use of a high-energy radiation source (e.g., MV). Images generated with kV energy may have better tissue contrast than images generated with MV energy. High-quality volumetric imaging may be required for visualization of the target and organs at risk (OARS), for adaptive therapy monitoring, and for treatment planning / replanning. In some embodiments, a kV imaging system may also be used for localization, motion tracking, and / or characterization or correction capabilities.

[0038] Image acquisition methods can include or otherwise utilize multi-rotation scanning, which can be, for example, continuous scanning (e.g., having a helical source trajectory about a central axis and longitudinal movement of a patient support through a gantry aperture), discontinuous circular stop-and-reverse scanning with incremental longitudinal movement of the patient support, etc.

[0039] According to various embodiments, an x-ray imaging device collimates a radiation source, using, for example, a beamformer, to include, for example, a cone beam or a fan beam. In one embodiment, the collimated beam can be combined with a gantry that rotates continuously while the patient moves, resulting in helical image acquisition.

[0040] In some embodiments, the time associated with additional scan rotations to complete a high-quality volume image can be mitigated by high gantry rate / speed (e.g., using fast slip-ring rotation, including, for example, up to 10 revolutions per minute (rpm), up to 20 rpm, up to 60 rpm, or higher rpm), high kV frame rate, and / or sparse data reconstruction techniques to provide kV CT imaging on a radiation therapy delivery platform. Detectors (having various row / slice sizes, configurations, dynamic ranges, etc.), scan pitch, and / or dynamic collimation are additional features in various embodiments, including selectively exposing portions of the detector and selectively defining an effective readout region.

[0041] The helical scan trajectory has several advantages over circular scanning. For example, since helical scanning can provide more complete projection data for image reconstruction, cone beam artifacts are reduced. Also, helical scanning can acquire projection data with large longitudinal coverage and a narrow axial opening, which can substantially reduce scatter contamination in the projection data. The reconstructed images can have significantly improved image quality in terms of low-frequency artifacts and result in a great enhancement of soft tissue contrast. Additionally, helical scanning can increase the scan speed at a large pitch.

[0042] Reference Figure 1 and Figure 2 , shows an x-ray imaging device 10. It will be understood that the x-ray imaging device 10 can be associated with and / or integrated into a radiation therapy device (such as Figure 2As shown, the radiological diagnostic and therapeutic equipment can be used for various applications, including but not limited to IGRT. The x-ray imaging device 10 includes a rotatable gantry system, referred to as gantry 12, supported by or otherwise housed within a support unit or housing 14. As used herein, gantry refers to a gantry system that includes one or more gantries (e.g., rings or C-arm), which is capable of supporting one or more radiation sources and / or associated detectors when the one or more radiation sources and / or associated detectors rotate around a target. For example, in one embodiment, a first radiation source and its associated detector can be mounted to a first gantry of the gantry system, and a second radiation source and its associated detector can be mounted to a second gantry of the gantry system. In another embodiment, more than one radiation source and associated detector(s) can be mounted to the same gantry of the gantry system, including, for example, where the gantry system includes only one gantry. Various combinations of gantries, radiation sources, and radiation detectors can be combined into various gantry system configurations to image and / or treat the same volume within the same device. For example, kV and MV radiation sources can be mounted on the same or different gantries of the gantry system and selectively used for imaging and / or treatment as part of an IGRT system. If mounted on different gantries, the radiation sources can rotate independently, but still be able to image the same (or nearly the same) volume simultaneously. As described above, the rotatable ring gantry 12 is capable of reaching 10 rpm or higher. The rotatable gantry 12 defines a gantry aperture 16 through which a patient can move in and pass through, and be positioned for imaging and / or treatment. According to one embodiment, the rotatable gantry 12 is configured as a slip-ring gantry to provide continuous rotation of the imaging radiation source (e.g., x-ray) and the associated radiation detector, while providing sufficient bandwidth for high-quality imaging data received by the detector. The slip-ring gantry can eliminate gantry rotation in alternating directions in order to wind and unwind the cables carrying power and signals associated with the device. Even when integrated into an IGRT system, such a configuration will allow continuous helical (e.g., fan beam, cone beam, etc.) computed tomography.

[0043] The patient support 18 or the bed / couch is positioned adjacent to the rotatable gantry 12 and is configured to generally support the patient in a horizontal position for longitudinal movement into or within the rotatable gantry 12. The patient support 18 can move the patient, for example, in a direction perpendicular to the rotation plane of the gantry 12 (along or parallel to the rotation axis of the gantry 12). The patient support 18 can be operatively coupled to a patient support controller for controlling the movement of the patient and the patient support 18. The patient support controller can be synchronized with the rotatable gantry 12 and the radiation source mounted to the rotatable gantry for rotation about the patient's longitudinal axis according to commanded imaging and / or treatment planning. In some embodiments, once the patient support is in the aperture 16, the patient support can also be moved up and down, left and right within a limited range to adjust the patient position for optimal treatment.

[0044] As Figure 2 shown, the x-ray imaging device 10 includes an imaging radiation source 30 coupled to or otherwise supported by the rotatable gantry 12. The imaging radiation source 30 emits a radiation beam (generally designated 32) for generating high-quality images. In this embodiment, the imaging radiation source is an x-ray source 30, which is configured as a kilovolt (kV) source (e.g., a clinical x-ray source having an energy level in the range of about 20 kV to about 150 kV). In one embodiment, the kV radiation source includes a peak photon energy in kiloelectron volts (keV) of up to 150 keV. The imaging radiation source can be any type of transmission source suitable for imaging. For example, the imaging radiation source can be, for example, an x-ray generating source (including for CT) or any other means of generating photons having sufficient energy and flux (e.g., a gamma source (e.g., cobalt-57, energy peak at 122 keV), an x-ray fluorescence source (e.g., a fluorescence source via Pb k-lines, two peaks at approximately 70 keV and approximately 82 keV), etc.). The references herein to x-rays, x-ray imaging, x-ray imaging sources, etc. are exemplary for particular embodiments. In various other embodiments, other imaging transmission sources can be used interchangeably. An x-ray detector 34 (e.g., a two-dimensional planar detector or a curved detector) can be coupled to or otherwise supported by the rotatable gantry 12. The x-ray detector 34 is positioned to receive radiation from the second x-ray source 30 and can rotate along with the x-ray source 30. The detector 34 can detect or otherwise measure the amount of unattenuated radiation and thus infer the radiation actually attenuated by the patient or the associated patient ROI (by comparison with the initially generated radiation). As the x-ray radiation source 30 rotates around the patient and emits radiation towards the patient, the detector 34 can detect or otherwise collect attenuation data from different angles.

[0045] It will be understood that the x-ray detector 34 can be configured in several ways without departing from the scope of the disclosed technology. As Figure 2As shown, the x-ray detector 34 can be configured as a flat panel detector (e.g., a multi-row flat panel detector). According to another exemplary embodiment, the x-ray detector 34 can be configured as a curved detector. The detector 34 can be adjusted to an offset (i.e., shifted) position in the channel and / or axial direction.

[0046] Although Figure 1 and 2 FIG. depicts an x-ray imaging apparatus 10 having a radiation source 30 mounted to a gantry 12, other embodiments may include other types of rotatable imaging devices, such as those including C-arm gantries and robot arm-based systems. In a gantry-based system, the gantry rotates the imaging radiation source 30 about an axis passing through the isocenter. Gantry-based systems include C-arm gantries, where the imaging radiation source 30 is mounted in a cantilever fashion on an axis passing through the isocenter and rotates about that axis. Gantry-based systems also include ring gantries, such as a rotatable gantry 12 having a generally toroid shape, where the patient's body extends through the aperture of the ring / loop and the imaging radiation source 30 is mounted on the periphery of the ring and rotates about an axis passing through the isocenter. In some embodiments, the gantry 12 rotates continuously. In other embodiments, the gantry 12 utilizes a cable-based system that rotates and reverses repeatedly.

[0047] A collimator or beam former assembly (generally denoted as 36) is positioned relative to the x-ray source 30 to selectively control and adjust the shape of the radiation beam 32 emitted by the x-ray source 30 to selectively expose a portion or region of the active area of the x-ray detector 34. The beam former 36 can also control how the radiation beam 32 is positioned on the x-ray detector 34. In one embodiment, the beam former 36 can have one degree / dimension of motion (e.g., to form a thinner or thicker slit). In another embodiment, the beam former 36 can have two degrees / dimensions of motion (e.g., to form rectangles of various sizes). In other embodiments, the beam former 36 can have various other dynamically controlled shapes, including for example a parallelogram. All of these shapes can be adjusted dynamically during a scan. In some embodiments, the blocking portion of the beam former can rotate and translate.

[0048] The beam former 36 can be controlled to dynamically adjust the shape of the radiation beam 32 emitted by the x-ray source 30 in several geometries, including but not limited to a beam thickness (width) as low as one detector row width or a fan beam or cone beam including multiple detector rows, which will be only a part of the active area of the detector. In various embodiments, the thickness of the beam can expose a larger detector active area of several centimeters. For example, 3-4 centimeters (measured longitudinally in the detector plane) of a 5-6 centimeter detector can be selectively exposed to the imaging radiation 32. In this embodiment, 3-4 centimeters of projection image data can be captured at each readout, with an unexposed detector area of approximately 1-2 centimeters on one or each side, which can be used to capture scatter data, as described below.

[0049] In other embodiments, more or less of the portion of the active detector 34 can be selectively exposed to the imaging radiation. For example, in some embodiments, the beam thickness can be reduced to a range of about two centimeters, one centimeter, less than one centimeter, or similar dimensions, including using smaller detectors. In other embodiments, the beam thickness can be increased to a range of about 4 centimeters, 5 centimeters, greater than 5 centimeters or similar dimensions, including larger detectors. In various embodiments, the ratio of the exposed detector area to the active detector area can be 30-90% or 50-75%. In other embodiments, the ratio of the exposed detector area to the active detector area can be 60-70%. However, in other embodiments, various other dimensions of the exposed area and the active area or the ratio of the exposed detector area to the active detector area can be suitable. The beam and the detector can be configured such that the shadow area of the detector (active but not exposed to direct radiation) is sufficient to capture scatter data outside the penumbra region.

[0050] Various embodiments can include optimization of features that control the selective exposure of the detector 34 (e.g., beam size, beam / aperture center, collimation, pitch, detector readout range, detector readout center, etc.) such that the measured data is sufficient for the primary (exposed) region and the shadow region and is also optimized for speed and dose control. The shape / position of the beam former 36 and the readout range of the x-ray detector 34 can be controlled such that the radiation beam 32 from the x-ray source 30 covers as much or as little of the x-ray detector 34 as based on the particular imaging task being performed. The beam 32 can be shaped into various shapes, including for example a parallelogram. The beam former 36 can be configured to adjust the shape of the emitted beam 32 by rotation and / or translation of the x-ray attenuation material of the beam former 36.

[0051] The collimator / beamformer 36 can be configured in a variety of ways to allow it to adjust the shape of the radiation beam 32 emitted by the x-ray source 30. For example, the collimator 36 can be configured to include a set of jaws or other suitable members that define and selectively adjust the size of the aperture through which the radiation beam from the x-ray source 30 can pass. According to an exemplary configuration, the collimator 36 can include an upper jaw and a lower jaw, where the upper jaw and the lower jaw can be moved in different directions (e.g., parallel directions) to adjust the size of the aperture through which the radiation beam from the x-ray source 30 passes, and also to adjust the position of the beam relative to the patient to irradiate only the portion of the patient to be imaged, for optimizing imaging and minimizing patient dose.

[0052] According to one embodiment, the shape of the radiation beam 32 from the x-ray source 30 can be changed during image acquisition. In other words, according to an exemplary implementation, the blade positions and / or aperture widths of the beamformer 36 can be adjusted before or during the scan. For example, according to one embodiment, the beamformer 36 can be selectively controlled and dynamically adjusted during the rotation of the x-ray source 30 such that the radiation beam 32 has a shape with sufficient primary / shadow regions and is adjusted to include only the object of interest (e.g., the prostate) during imaging. The shape of the radiation beam 32 emitted by the x-ray source 30 can be changed during or after the scan depending on the desired image acquisition, which can be based on imaging and / or diagnostic feedback, as discussed in more detail below.

[0053] As Figure 2 shown, the x-ray imaging device 10 can be integrated with a radiation treatment device that includes a therapeutic radiation source 20 coupled to or otherwise supported by the rotatable gantry 12. According to one embodiment, the therapeutic radiation source 20 is configured as a source of therapeutic radiation, such as a high-energy radiation source for treating tumors in an area of interest within a patient. It will be understood that the source of therapeutic radiation can be a high-energy x-ray beam (e.g., a megavoltage (MV) x-ray beam) and / or a high-energy particle beam (e.g., an electron beam, a proton beam, or a beam of heavier ions, such as carbon) or other suitable forms of high-energy radiation. In one embodiment, the first radiation source 20 includes a peak photon energy of 1 MeV or greater in megaelectron volts (MeV). In one embodiment, the high-energy x-ray beam has an average energy greater than 0.8 MeV. In another embodiment, the high-energy x-ray beam has an average energy greater than 0.2 MeV. In another embodiment, the high-energy x-ray beam has an average energy greater than 150 keV. Generally, the first radiation source 20 has a higher energy level (peak and / or average, etc.) than the second radiation source 30.

[0054] In one embodiment, the therapeutic radiation source 20 is a linear accelerator (LINAC) that produces therapeutic radiation (e.g., an MV source), and the imaging system includes an independent x-ray imaging radiation source 30 (e.g., a kV source) that produces relatively low-intensity and low-energy imaging radiation. In other embodiments, the therapeutic radiation source 20 can be a radioisotope, such as cobalt-60, which typically has an energy of >1 MeV. The therapeutic radiation source 20 can emit one or more radiation beams (generally denoted by 22) according to a treatment plan into a region of interest (ROI) within a patient supported on the patient support 18. In some embodiments, the therapeutic radiation source 20 can be used for imaging.

[0055] The detector 24 can be coupled to or otherwise supported by the rotatable gantry 12 and is positioned to receive the radiation 22 from the therapeutic radiation source 20. The detector 24 can detect or otherwise measure the amount of unattenuated radiation and thus infer the radiation actually attenuated by the patient or the associated patient ROI (by comparison with the initially generated radiation). As the therapeutic radiation source 20 rotates around the patient and emits radiation at the patient, the detector 24 can detect or otherwise collect attenuation data from different angles.

[0056] It will also be understood that the therapeutic radiation source 20 can include a collimator or otherwise be associated with a collimator. The collimator associated with the therapeutic radiation source 20 can be configured in a variety of ways, similar to the collimator / beam former 36 associated with the imaging source 30. For example, the collimator / beam former can be configured as a multi-leaf collimator (MLC), which can include a plurality of interleaved blades that are operable to move to one or more positions between a minimum open or closed position and a maximum open position. It will be understood that the blades can be moved to a desired position to achieve a desired shape of the radiation beam emitted by the radiation source. In one embodiment, the MLC can have a target localization accuracy of sub-millimeters.

[0057] The therapeutic radiation source 20 can be mounted, configured, and / or moved into the same plane or a different plane (offset) as the imaging source 30. In some embodiments, the scatter caused by the simultaneous activation of the radiation sources 20, 30 can be gradually reduced by offsetting the radiation planes.

[0058] When integrated with a radiological diagnostic and treatment device, the x-ray imaging device 10 can provide images for setting (e.g., aligning and / or registering), planning, and / or guiding a radiation delivery process (treatment). A typical setting is accomplished by comparing the current (during treatment) image with pre-treatment image information. The pre-treatment image information can include, for example, computed tomography (CT) data, cone-beam CT data, magnetic resonance imaging (MRI) data, positron emission tomography (PET) data, or 3D rotational angiography (3DRA) data and / or any information obtained from these or other imaging modalities. In some embodiments, the x-ray imaging device 10 can track the in-treatment patient, target, or ROI movement.

[0059] The reconstruction processor 40 can be operatively coupled to the detector 24 and / or the x-ray detector 34. In one embodiment, the reconstruction processor 40 is configured to generate a patient image based on the radiation received by the x-ray detector 34 from the x-ray source 30. It will be understood that the reconstruction processor 40 can be configured to perform the methods described more fully below. The device 10 can also include a memory 44, which is adapted to store information, including but not limited to, processing and reconstruction algorithms and software, imaging parameters, image data from previously or otherwise previously acquired images (e.g., planning images), treatment planning, etc.

[0060] The x-ray imaging device 10 can include an operator / user interface 48, where the operator of the x-ray imaging device 10 can interact with or otherwise control the x-ray imaging device to provide inputs related to, for example, scan or imaging parameters, etc. The operator interface 48 can include any suitable input device, such as a keyboard, a mouse, a voice-activated controller, etc. The x-ray imaging device 10 can also include a display 52 or other human-readable element to provide an output to the operator of the x-ray imaging device 10. For example, the display 52 can allow the operator to observe the reconstructed patient image and other information related to the operation of the x-ray imaging device 10, such as imaging or scan parameters.

[0061] As Figure 2As shown, the x-ray imaging device 10 includes a controller (generally designated 60) operatively coupled to one or more components of the device 10. The controller 60 controls the overall function and operation of the device 10, including providing power and timing signals to the x-ray source 30 and / or the diagnostic radiation source 20, and a gantry motor controller that controls the rotational speed and position of the rotatable gantry 12. It will be understood that the controller 60 may include one or more of the following: a patient support controller, a gantry controller, a controller coupled to the diagnostic radiation source 20 and / or the x-ray source 30, a beamformer 36 controller, a controller coupled to the detector 24 and / or the x-ray detector 34, etc. In one embodiment, the controller 60 is a system controller that can control other components, devices, and / or controllers.

[0062] In various embodiments, the reconstruction processor 40, the operator interface 48, the display 52, the controller 60, and / or other components may be combined into one or more components or devices.

[0063] The device 10 may include various components, logic, and software. In one embodiment, the controller 60 includes a processor, a memory, and software. By way of example and not limitation, the x-ray imaging device and / or the radiation therapy system may include various other devices and components (e.g., a gantry, a radiation source, a collimator, a detector, a controller, a power supply, a patient support, etc.) that may implement one or more routines or steps related to imaging and / or IGRT for a particular application, where the routines may include imaging, image-based pre-delivery steps, and / or treatment delivery, including corresponding device settings, configurations, and / or positions (e.g., paths / trajectories) that may be stored in the memory. Additionally, the (one or more) controllers may directly or indirectly control one or more devices and / or components according to one or more routines or processes stored in the memory. Examples of direct control are setting various radiation source or collimator parameters (power, speed, position, timing, modulation, etc.) related to imaging or treatment. An example of indirect control is transmitting positions, paths, speeds, etc. to a patient support controller or other peripheral devices. The hierarchy of the various controllers that may be associated with the x-ray imaging device may be arranged in any suitable manner to transmit appropriate commands and / or information to the desired devices and components.

[0064] In addition, those skilled in the art will understand that other computer system configurations can be utilized to implement the system and method. The illustrated aspects of the present invention can be implemented in a distributed computing environment where certain tasks are performed by local or remote processing devices linked through a communication network. For example, in one embodiment, the reconstruction processor 40 can be associated with a separate system. In a distributed computing environment, program modules can be located in local and remote memory storage devices. For example, a remote database, a local database, a cloud computing platform, a cloud database, or a combination thereof can be utilized together with the x-ray imaging device 10.

[0065] The x-ray imaging device 10 can utilize an exemplary environment for implementing various aspects of the present invention, including a computer, where the computer includes a controller 60 (e.g., including a processor and a memory, which can be the memory 44) and a system bus. The system bus can couple system components including, but not limited to, the memory to the processor and can communicate with other systems, controllers, components, devices, and processors. The memory can include a read-only memory (ROM), a random access memory (RAM), a hard disk drive, a flash drive, and any other form of computer-readable medium. The memory can store various software and data, including routines and parameters, which can include, for example, treatment planning.

[0066] The diagnostic radiation source 20 and / or the x-ray source 30 can be operably coupled to the controller 60, which is configured to control the relative operation of the diagnostic radiation source 20 and the x-ray source 30. For example, the x-ray source 30 can be controlled and operated simultaneously with the diagnostic radiation source 20. Additionally, or alternatively, the x-ray source 30 can be controlled and operated sequentially with the diagnostic radiation source 20, depending on the specific treatment and / or imaging plan implemented.

[0067] It will be understood that the x-ray source 30 and the x-ray detector 34 can be configured to provide rotation around the patient in several ways during an imaging scan. In one embodiment, synchronizing the movement and exposure of the x-ray source 30 with the longitudinal movement of the patient support 18 can provide continuous helical acquisition of patient images during operation. In addition to the continuous rotation of the radiation sources 20, 30 and the detector(s) 24, 34 (e.g., continuous and constant rotation of the gantry with a constant patient movement speed), it will be understood that other variations can be employed without departing from the scope of the disclosed technology. For example, the rotatable gantry 12 and the patient support can be controlled such that when the support is controlled to move (at a constant or variable speed) relative to the rotatable gantry 12, the gantry 12 rotates around the patient supported on the patient support in a "back-and-forth" manner (e.g., alternating clockwise and counterclockwise rotation) (as described above, as opposed to "continuously"). In another embodiment, in a circular scan by continuous step-and-shoot, the movement (step) of the patient support 18 in the longitudinal direction alternates with the scan rotation of the rotatable gantry 12 (shoot) until the desired volume is captured.

[0068] Relative movement of the radiation source and the patient to generate projection data can be achieved using various other types of radiation sources and / or patient support movement. Discontinuous movement, continuous but variable / non-constant (including linear and non-linear) movement, speed, and / or trajectory, etc. of the radiation source and / or the patient support, and combinations thereof, including combinations with various embodiments of the above-described radiation diagnostic and treatment device 10, can be used.

[0069] In one embodiment, the gantry 12 rotation speed, the patient support 18 speed, the beamformer 36 shape, and / or the detector 34 readout can all be constant during one or more passes of image acquisition. In other embodiments, one or more of these variables can be changed dynamically during one pass of image acquisition or between multiple passes of image acquisition. The gantry 12 rotation speed, the patient support 18 speed, the beamformer 36 shape, and / or the detector 34 readout can be changed to balance different factors, including, for example, image quality and image acquisition time.

[0070] In other embodiments, these features can be combined with one or more other image-based activities or processes, including, for example, patient setup, adaptive diagnostic monitoring, treatment planning, etc.

[0071] Images are typically required at different stages during radiotherapy. For example, during a treatment fraction, they are used for patient positioning at an early stage and for dose calculation at a later stage. The image quality requirements for patient positioning are lower than those for dose calculation. As described above, the images acquired on an IGRT system have two main uses: treatment setup (e.g., registration with the planning CT image used for patient setup); and treatment planning (e.g., adaptive planning and / or dose calculation). The requirements for the images can be different for these two applications. For treatment setup, the accuracy of image quantification (e.g., CT numbers) is not as critical as for treatment planning. For example, imaging with a relatively large axial field of view (FOV) may be sufficient for treatment setup but not for treatment planning.

[0072] For a typical treatment, the total treatment time per delivery fraction can include CT scan time, CT reconstruction time, registration time of the CT image with the planning CT image, and treatment planning setup time. Conventional IGRT systems typically acquire a set of CT images for both treatment setup and treatment planning. In this way, the workflow for patient treatment may not be optimal because the image requirements for treatment setup may be less.

[0073] Most IGRT systems with CT scanning capabilities use CBCT scans with circular scans. When a relatively large axial range needs to be scanned, multiple circular scans can be performed with some overlap between adjacent scans. If the images are also used for dose calculation, sufficient scan time is required for each circular scan to make the images accurate for dose calculation. This workflow involves waiting until all circular scans are completed and reconstructing the resulting images before using the images for registration with the planning CT image and treatment setup. To improve the overall treatment workflow (minimize the total treatment time), one approach involves reducing the number of circular scans or reducing the scan time per circular scan to achieve a satisfactory compromise among the CT scan range, scan time, image quality, and total registration / setup time.

[0074] IGRT systems with helical CT scanning capabilities can perform continuous scans in the axial direction. However, overall workflow optimization may also require a compromise among the CT scan range, pitch, total scan time, image quality, and total registration / setup time.

[0075] As described herein, multi-pass imaging scans can be used to optimize the workflow, including for example reducing the time required for pre-delivery steps. This optimization can be applied via the use of an IGRT system having circular and / or helical CT scan capabilities. Generally, by dividing or segmenting the imaging scan into multiple passes, each pass acquiring / generating different and / or complementary data that can be used at different steps of the workflow, the pre-delivery (and overall treatment) workflow can be improved. The data can be used alone (e.g., for reconstruction) or in combination with earlier data. At least one pass is completed and utilized in less time than it takes to complete the entire imaging scan. The first pass can be optimized to generate the data required for the initial steps of the workflow, which can include treatment setup (e.g., registration) and / or any other treatment pre-planning activities. Once the first pass is completed, the initial steps of the workflow can begin based on the first pass data while the second pass of the imaging scan is being performed. The second pass (and any other subsequent passes) can generate the remaining data required for the remaining workflow steps. In some ways, the second pass can be considered dead time because the patient support must be moved off the gantry anyway - it can be better use of time to defer some scans during this movement.

[0076] In this way, the initial steps of the workflow can be started and completed earlier in the workflow (i.e., rather than waiting for a full scan). Additionally, in various embodiments, the total dose can be maintained or even reduced via optimization. The first pass data can be used to determine the scan parameters for subsequent passes, further optimizing time, image quality, dose, etc. In some embodiments, more than two passes can be utilized for various combinations and workflows with different improvements.

[0077] The different scans of the multi-pass technique can have different scan designs (e.g., different parameters). For example, dose, spectrum (dual energy), view sampling, detector position, detector resolution, collimation (e.g., narrow first and wide second), energy, scan speed (including for example pitch) and / or type (e.g., helical, step-and-shoot, etc.) etc. can vary between scans. The various combinations of these parameters are different in various embodiments.

[0078] The system for implementing the imaging scan can include a radiation source, which can be kV or MV, including having corresponding kV or MV detectors, as described above. The radiation source can also include different spectra, which can be for example a segmented or dual-beam setup using advanced collimator designs. In some exemplary embodiments, the system can operate at up to 10 rpm for imaging and 6 rpm for treatment. Conventional CT is too fast (e.g., approximately 200 rpm) to implement these techniques. Various beam shapes can be used, including fan beam and cone beam.

[0079] In some embodiments, the first pass is performed with a relatively short scan time, but has sufficient image quality for registration / treatment setup. Then, after the first pass and while processing (e.g., reconstructing and registering) the first pass data, a second pass can be performed for treatment setup, thus reducing the workflow time. A fast reconstruction algorithm and reconstruction parameters (e.g., image size) can be utilized to reconstruct the first pass data to minimize the reconstruction time. Data from all scan passes can be used to reconstruct the final image using an advanced reconstruction algorithm for treatment planning (e.g., dose calculation and adaptive planning).

[0080] For example, in one embodiment, the first pass uses a sparse scan protocol that acquires fewer data views than a traditional single scan, while the second pass acquires data in another set of views that are interleaved with the views from the first pass. The combined data from the two passes will have combined (e.g., full) views that can be equal to or greater than a traditional scan. In another embodiment, the second pass can use a different energy than the first pass, and the combined data from the two passes provides not only sufficient angular resolution but also spectral data. In another embodiment, the first pass and the second pass acquire different numbers of views such that the combined data has views that are evenly distributed angularly or has views that are denser in some angular regions than in other angular regions.

[0081] In some embodiments, the first pass image and the planning image can provide optimized scan parameters for the second pass scan when registered and analyzed. For example, the scan parameters can be optimized for the movement speed of the patient support, pitch, collimation, pulse rate of the imaging radiation, energy level (e.g., "color"), mA (e.g., number of x-rays), and / or gantry rotation speed. These parameters can also vary for different axial regions during the same pass.

[0082] In various embodiments, the movement of the imaging radiation source 30 and the radiation detector 34 via the movement of the gantry 12 can be coordinated with the movement of the patient support 18 to implement various imaging scan designs using multiple scan runs. These movements can be controlled according to various scan protocols, and the generated projection data is processed (e.g., including via the controller 60 and the processor 40) to perform various steps of the treatment workflow, including, for example, image reconstruction, registration, related data processing, storage, communication, etc. within the IGRT system for treatment setup, treatment planning, and / or treatment delivery. For example, in one embodiment, a step-and-shoot circular scan can be used. In another embodiment, the movement of the patient support 18 and the gantry 12 can be coordinated at a constant speed to perform a helical scan. In another embodiment, the patient support 18 and / or the gantry 12 move relative to each other at variable speeds. The speeds of the patient support 18 and the gantry 12 can vary such that the time required to complete the first run is less than the time required to complete the second run, including creating various pitches of the helical scan or the step distances of the circular scan.

[0083] For example, in one embodiment, the first run of the imaging scan is a fast helical CT scan, and the resulting image is reconstructed with sufficient image quality for treatment setup (e.g., registration). When the image is sent to the workstation for treatment setup, the second run of the imaging scan is another helical CT scan performed by reversing the direction of patient table movement. In this embodiment, the registration / treatment setup and the second run of the imaging scan can occur simultaneously, reducing the total workflow time compared to the conventional method of acquiring a set of high-quality CT images for treatment setup and treatment planning (for each treatment fraction).

[0084] In this embodiment, the second run scan can have the same scan range as the first run scan, and the total patient dose can be the same as or lower than the conventional method of acquiring a set of CT images during one run.

[0085] In some embodiments, according to the registration and / or setup results using the first run data, the second run scan parameters can be adjusted, including, for example, limiting the scan to only the axial range of interest, which can be one segment or multiple segments.

[0086] In other embodiments, the first run can also be used to adjust the imaging dose at different axial regions during the second run, thereby optimizing the dose distribution in the scan range to obtain the best image quality in regions of greater attenuation while maintaining the same total patient dose.

[0087] In some embodiments, according to the registration results with the planning CT and / or the treatment pre-planning results using the first run data, when higher resolution is required in certain axial ranges, the second run can use different scan parameters, including, for example, different or varying pitch sizes in different axial ranges of the second run.

[0088] In other embodiments, even if treatment planning does not begin until the imaging scan is complete, multi-pass imaging scans can be used to generate high-quality images more quickly, including, for example, by beginning reconstruction of the first-pass data during the second pass.

[0089] For example, the technique can be used to generate spectral images. Two or more helical scan passes at different tube energies can generate data / images from multiple CT passes, which can be used to generate spectral images, including electron density images, material decomposition images, etc. In one embodiment, the second pass can use a different kV energy than the first pass, such that the two scans allow spectral CT reconstruction. The resulting spectral CT can then be used to improve dose calculation and adaptive planning.

[0090] Reference Figure 3 , shows a diagram 300 of an x-ray imaging device 10 with a defined world coordinate system 310. The origin (denoted as O) is the isocenter of the gantry 12 and the unit vectors associated with the x, y, and z axes are shown respectively as e x , e y and e z . When viewed from the front of the gantry 12, the x-axis e x is horizontal and points to the right, the y-axis e y points into the gantry plane, and the z-axis e z is vertical and points to the top. The x, y, and z axes follow the right-hand rule.

[0091] In an exemplary embodiment, when viewed from the front of the gantry 12, the x-ray source 30 rotates clockwise. Figures 4 - 5 Shows the movement of the gantry 12 and the patient support 18 during an exemplary scan pass of an imaging scan. In particular, during the first pass of a dual-helical scan, when looking into the gantry 12, the patient support 18 moves into the gantry 12 (along the y-axis e y ), while the gantry rotates in an exemplary clockwise direction (about the y-axis e y ). During the second pass of the dual-helical scan, the patient support 18 moves out of the gantry 12 while the gantry rotates in the same exemplary clockwise direction. During the imaging scan, data acquisition in the axial direction can be offset, as discussed in more detail below. In other embodiments, any number of passes can be used to complete the imaging scan.

[0092] In one embodiment, for an improved workflow, a two-pass helical scan protocol can be used on an IGRT system with helical scan capabilities. In particular, after the patient is positioned on the patient support 18, a first-pass helical scan is performed while the patient support 18 is moved into the gantry 12 (e.g., as shown in Figure 4 ), generating first-pass projection data. Reconstructing the first-pass projection data into a first patient image can occur simultaneously with the first pass. After the first pass, by reversing the direction of movement of the patient support 18, a second-pass helical scan is performed such that the patient support 18 is moved out of the gantry 12 (e.g., as shown in Figure 5 ), and for example, while other scan parameters can remain the same, generating second-pass projection data. The first patient image from the first-pass helical scan can be used for registration with the planning image and treatment setup while performing the second-pass helical scan, reducing the total time for imaging scans and treatment setup, and thus improving the overall treatment workflow.

[0093] In another embodiment, a two-pass helical scan protocol can be used on an IGRT system with helical scan capabilities for differential axial scan optimization. In particular, when the patient support 18 is moved into the gantry 12 (e.g., as shown in Figure 4 ), a first-pass helical scan is performed, generating first-pass projection data. Reconstructing the first-pass projection data into a first patient image can occur simultaneously with the first pass. After the first scan, the first patient image is registered with the planning CT, and axial regions are identified to obtain better resolution or improved statistics. When the patient support 18 is moved out of the gantry 12 (e.g., as shown in Figure 5 ), this information can be used to set or adjust the scan parameters for the second-pass helical scan. The identified regions can have desired resolution and statistics to improve the accuracy of treatment planning, which includes for example dose calculation and adaptive planning.

[0094] In another embodiment, a multi-pass helical scan protocol can be used on an IGRT system with helical scan capabilities for spectral CT imaging. In particular, when the patient support 18 is moved into the gantry 12 (e.g., as shown in Figure 4 ), a first-pass helical CT scan is performed using one tube energy, while when the patient support 18 is moved out of the gantry 12 (e.g., as shown in Figure 5 ), another pass of the helical CT scan is performed using a different tube energy. The multi-pass provides data for spectral CT image reconstruction. The resulting spectral CT images can be used for treatment planning, including for example accurate dose calculation and adaptive planning.

[0095] In another embodiment, additionally referring to Figure 6, a fast scan can be performed using a two-pass helical scan protocol with a large pitch. In this embodiment, the beamformer aperture and the detector active area can be located on one side with a very large pitch such that during the second pass, the beamformer aperture and the detector active area are located on the other side with the same pitch relative to the first pass. Exemplary imaging scan design 600 shows the relative positions of the radiation source 30 and the radiation detector 34 during the two passes of the imaging scan. In particular, while the patient support 18 is moved into the gantry 12 (e.g., as Figure 4 shown) to expose the detector 34 shown at the first detector position 612 (detector position I), the first-pass helical CT scan 610 (scan I) of the imaging scan is performed. While the patient support 18 is moved out of the gantry 12 (e.g., as Figure 5 shown) to expose the detector 34 shown at the second detector position 622 (detector position II), the second-pass helical CT scan 620 (scan II) of the imaging scan is performed. A large pitch is used for each of the two passes 610, 620 of the imaging scan, but during the second pass 620, the detector 34 and the source 30 are moved in the axial direction (along the y-axis e y ) relative to the first pass 610 so that the data from the two passes can be interleaved. When the data from the two passes 610, 620 are used jointly, the data sufficiency of the complete imaging scan is improved compared to each of the two passes 610, 620, thus allowing high-quality image reconstruction. However, the first pass 610 with a large pitch allows for a faster (and earlier) scan and reconstruction, which can improve the workflow. For example, when the first-pass 610 data are used for treatment setup during the second pass 620, the workflow and the total treatment time are thereby reduced. In different embodiments, the CT scan system can be a cone-beam CT system with a flat-panel CT detector, a conventional multi-detector CT system, a single-row CT system, etc.

[0096] In another embodiment, the two passes of the imaging scan can include offset detectors in the scan design. Cone-beam CT (CBCT) is a prevalent imaging tool for IGRT. Typical CBCT systems employ flat-panel detectors 34, which are generally not large enough to enclose the entire cross-section of the patient. Eccentric or offset detectors can be used for circular scans with a large FOV. Using an eccentric detector configuration during helical scans involves substantially more lateral data truncation. Due to this severe lateral data truncation, the image quality depends largely on the helical pitch. Compared to helical scans without lateral data truncation, the maximum feasible pitch of helical scans with lateral truncation decreases significantly, and the scan speed also decreases significantly.

[0097] In this embodiment, the two-pass imaging scan for data acquisition consists of two helices. In the first pass, the patient support 18 is moved into the gantry 12 (e.g., asFigure 4 as shown), where the detector 34 is shifted to a lateral side. In the second pass, the patient support 18 is moved out of the gantry 12 (e.g., as Figure 5 shown), while the detector 34 is shifted to the opposite side. The lateral detector translation between the two helices is designed to improve the data availability for image reconstruction. The data acquired from the first pass can be reconstructed for patient positioning, while the data from both passes can be used for improved image reconstruction eligible for dose calculation. In various embodiments, this type of two-pass helical imaging scan design can be referred to as a dual-helix trajectory. However, this dual-helix trajectory requires a dedicated image reconstruction algorithm.

[0098] Figure 7 and 8 show the geometry of an exemplary data acquisition system for this embodiment. As Figure 3 introduced in, the world coordinate system 310 is spanned by the (x, y, z) axes. Figure 7 shows a diagram 700 of the 3D geometry of an exemplary data acquisition system. Figure 8 shows a diagram 800 of the geometry of the data acquisition system in an exemplary (x, z) plane. In one exemplary embodiment, when viewed from the front of the gantry 12, the x-ray source 30 rotates clockwise, and the viewing angle λ is defined as the angular distance from the x-axis e x to the virtual line 702 connecting the source 30 and the rotation axis, when viewed from the front of the gantry 12, in a clockwise manner, and its vector position is represented as a(λ). The rotation axis is along the world coordinate y-axis e y . The detector 34 is positioned such that it is perpendicular to the plane defined by the source 30 and the rotation axis, its channels are parallel to the rotation axis, and its rows are perpendicular to the rotation axis. The piercing point of the line 702 connecting the source 30 and the isocenter O at the detector 34 is defined as the origin of the detector coordinate system 710, which is represented by O d .

[0099] As Figure 7 shown, the exemplary data acquisition system involves two coordinate systems. In particular, the data acquisition reference origin is at O in the world coordinate system 310 and at O d in the detector coordinate system 710. As described above, the detector coordinate system 710 is defined by the basis vectors e u (in the channel direction), e v in the plane of the detector 34 (in the row direction), and e w (perpendicular to the plane of the detector 34 and pointing from O d to a ). Here, O dis defined as along e w the line 702 that connects the source 30 (having a vector position a (λ)) and O and extends to the piercing point on the detector 34. And α (λ,u,v) is the unit vector 704 from the source 30 vector position a (λ) pointing to the detector 34 element at the coordinates [u, v] in the detector coordinate system 710.

[0100] Figure 8 shows the geometry 800 of the data acquisition system in an exemplary (x, z) plane. The x-ray source 30 is located in the (x, z) plane and rotates clockwise about the y-axis. The source-to-isocenter distance (SID) is denoted by R. The viewing angle or rotation angle is denoted by λ, which is defined as the clockwise angular distance from the x-axis. The x-ray source 30 is represented by a (λ). The detector 34 is placed 180° from the x-ray source with respect to the rotation axis. The source-to-detector distance (SDD) is denoted by D. The detector 34 is perpendicular to the plane connecting the source 30 and the y-axis, and its channels are parallel to the y-axis. The detector plane is indexed by the (u, v) coordinate system, where u is for the detector channel position and v is for the detector row position.

[0101] In this system, the x-ray detector 34 is an exemplary flat panel detector, and the basis vectors e u and e v span the 2D panel, where e u is for the channel direction, e v is for the row direction. The v-axis points in the same direction as the y-axis, and the u-axis points in the same direction as the rotational angular velocity. To extend the detector coordinate system to 3D, a w-axis can be introduced such that the (v, u, w) axes follow the right-hand rule.

[0102] As described above, the dual-helix scan design includes two complementary passes having a helical trajectory. Figure 9A shows the trajectory of an exemplary left-handed helix (LHH) 910, and Figure 9BShows the trajectory of an exemplary right - hand helix (RHH) 920, both are shown with a detector 34 offset. The LHH 910 is formed by moving the patient support (not shown) into the gantry and shifting the detector 34 to the +u axis, while the RHH 920 is formed by moving the patient support out of the gantry and shifting the detector 34 to the -u axis. As shown in this embodiment, the offset detector 34 is large enough such that the central x - ray (through the y - axis) is detected and the projection to the end of the offset direction is not truncated. The pitch of the two helices 910, 920 can generally be different, but is shown as the same here.

[0103] Regarding image reconstruction, it can be shown that for points within the convex hull of the helix, only one π - line is available, and if the point is visible along the entire π - segment, then exact image reconstruction of the points along the π - line is possible. For a typical helical scan without data truncation in the transverse direction, this condition is met as long as the detector is large enough to enclose the Tam - Danielsson (TD) window in the axial direction. For a large number of points in the scan field of view (SFOV) of a helical scan with an offset detector, this condition is not met.

[0104] Consider an exemplary dual - helix scan design with Figure 9A and 9B the trajectories 910, 920 shown, Figure 10 Figure 1000 shows an illustration of data availability in an exemplary transverse plane. The descriptions of the detector 34 during an exemplary left - hand helix (LHH) 910 pass and an exemplary right - hand helix (RHH) 920 pass are superimposed in the same transverse (x, z) plane 1010. The SFOV consists of a fully illuminated region 1020 and a partially illuminated region 1030. By construction, only the fully illuminated region 1020 is fully visible at all azimuth angles, while the partially illuminated region 1030 is only visible at some azimuth angles. For a single - helix scan with an offset detector, it can be shown that a large number of points in the partially illuminated region 1030 may not be fully visible along their only π - segment and thus cannot be accurately and stably recovered. It can also be shown that for such a trajectory with a large pitch, some points do not even have 180 - degree data (relative to the point itself) for back - projection, which may cause even greater difficulties in the reconstruction task due to the limited - angle problem.

[0105] The limited - angle problem can be avoided in a dual - helix trajectory, and thus the pitch requirement is relaxed compared to the single - helix case. One criterion for pitch selection in a dual - helix trajectory is that for any point in the ROI, there is always a large enough azimuth - angle range such that 180 - degree data is available for back - projection.

[0106] Based on the above observations, in this embodiment, the reconstruction algorithm includes backprojecting all available data using a weighting mechanism such that all backprojection weightings at the same azimuth and conjugate azimuth are normalized to 1. This weighting mechanism can be implemented via a pair of weighting functions for LHH and RHH denoted by w L and w R respectively. The reconstruction algorithm is based on the filtered backprojection (FBP) framework. Let and be the images reconstructed using data from LHH and RHH respectively. Let be the final reconstruction result.

[0107] The LHH reconstruction is described in Equation 1 below:

[0108]

[0109] where (u*, v*) is the stitching point of the x-ray passing through x at the detector 34. The term in Equation 1 is defined as follows in Equation 2:

[0110]

[0111] where h H (u) is the Hilbert transform and, according to Equation 3:

[0112]

[0113] where α (λ, u, v) refers to the unit vector from the source a(λ) to the detector point (u, v), and is the projection data with lateral truncation data estimated from adjacent rotations using known methods, and is the view-dependent differentiation that can be implemented using known schemes.

[0114] The reconstruction according to RHH can be obtained using the same equations (1, 2, 3) with R replacing the superscript L. According to Equation 4, the final image reconstruction of the double helix trajectory can be obtained as the sum of and :

[0115]

[0116] Figure 11Exemplary reconstructions 1100 of a thoracic phantom using a dual - helix scan design and the above - described reconstruction techniques using computer simulation are shown. In particular, 1110 is a reconstruction of a left - hand helix (LHH), 1120 is a reconstruction of a right - hand helix (RHH), and 1130 is a reconstruction of a dual - helix. 1140 is noiseless data, and 1150 is noisy data. The display window is 1000 HU. In this exemplary embodiment, a modified version of the FORBILD thoracic phantom is used for computer simulation. The SID and SDD are 1080 mm and 1620 mm, respectively. The detector 34 consists of 480 channels and 120 rows, with a pixel size of [0.9 mm, 0.9 mm]. The detector 34 is symmetric about the u - axis and is eccentric along u the axis. For the RHH and LHH, the channel offsets are set to 49.75 and 429.75, respectively. The starting viewing angles for the LHH and RHH are 0 and π, respectively. The two helices consist of 3 rotations with a longitudinal extent of 216 mm. For each detector pixel, the line integral is calculated as the average of four rays passing through its corner. Both the LHH and RHH use 480 views per rotation with a pitch of 1. Poisson noise (using 55k photon counts) and electronic noise (using 5 counts) are added to the projection data. For image reconstruction, the resolution parameter ε is set to 0.05. The image voxels are isotropic with an edge size of 1 mm. These reconstruction results show that the reconstruction algorithm can recover the FORBILD thoracic phantom with satisfactory image quality.

[0117] In this way, a dual - helix trajectory for imaging, including CBCT during IGRT, can be reconstructed. Compared with a single helix with a laterally - eccentric detector, the dual - helix trajectory can improve data availability, increase the scan speed, and reduce image noise. The configuration relationship between the two helices can significantly affect data availability and should be optimized.

[0118] The included flowcharts and block diagrams illustrate exemplary configurations and methods associated with multi - pass imaging scans according to the systems described herein. The exemplary methods can be executed in logic, software, hardware, or a combination thereof. Additionally, although the processes and methods are presented in a certain order, the blocks can be executed in a different order, including serially and / or in parallel. Moreover, additional steps or fewer steps can be used.

[0119] Figure 12is a flow diagram of an exemplary multi-pass imaging process 1200. Process 1200 may utilize the imaging system and scan design described above. An exemplary pre-delivery step of the workflow is shown as 1202. In this embodiment, the imaging scan includes at least two passes, where each pass acquires a portion of the data required for a full imaging scan. Each pass may be performed faster than a full scan. At step 1210, the system performs the first pass of the imaging scan (e.g., while moving the patient support into the gantry), generating first-pass data 1215. At step 1220, the system performs the second pass of the imaging scan (e.g., while moving the patient support out of the gantry), generating second-pass data 1225.

[0120] In this embodiment, the system may process (e.g., reconstruct) the first-pass data 1215 generated / received during the first pass 1210 while the system performs the second pass 1220. Next, at step 1230, the system may proceed with various data / image processing and image-based pre-delivery steps (e.g., see Figures 16 - 18 below), including treatment setup (e.g., reconstruction, registration, alignment, etc.) and treatment planning (e.g., dose calculation, adaptive planning, etc.). In this way, since the image processing of the first-pass data 1215 can occur during the second pass 1220, and since the time associated with returning from inside the gantry to the patient support can be used as scan time in 1220, the pre-delivery step 1202 can be completed faster using a multi-pass imaging scan (relative to a single-pass scan). After the treatment setup / planning 1230 is completed, the process may proceed to treatment delivery at step 1240, including as part of IGRT.

[0121] In one embodiment, the first pass 1210 may include a first tube energy of the imaging radiation source, and the second pass 1220 may include a second tube energy of the imaging radiation source. The first-pass data 1215 may be reconstructed into a first patient image, and the second-pass data 1225 may be reconstructed into a second patient image, such that the combined reconstructed first and second patient images produce a spectral patient image useful for the various treatment setup and treatment planning tasks described above.

[0122] In other embodiments, the imaging scan includes more than two passes 1210, 1220. Optional additional passes 1222 and additional associated pass data 1227 are shown in Figure 12 to represent that the imaging scan in these embodiments may include any number of scan passes.

[0123] Figure 13is a flow diagram of another exemplary multi-pass imaging process 1300. Process 1300 may utilize the imaging system and scan design described above. An exemplary pre-delivery step of the workflow is shown as 1302. In this embodiment, the imaging scan includes at least two passes, where each pass acquires a portion of the data required for a full imaging scan. Each pass may be performed faster than a full scan. At step 1310, the system performs the first pass of the imaging scan (e.g., while moving the patient support into the gantry), generating first-pass data 1315. In this embodiment, the system may utilize the first-pass data 1315 generated / received during the first pass 1310 before or simultaneously with the system performing the second pass 1320.

[0124] In various embodiments, the original and / or processed (e.g., reconstructed) first-pass data 1315 may be used before or simultaneously with the system performing the second pass 1320 to determine / adjust scan parameters associated with the second pass 1320 (as described above) and for various data / image processing and image-based pre-delivery steps (see, for example, Figures 16 - 18 below), including treatment setup 1330 (e.g., reconstruction, registration, alignment, etc., as described above) and / or treatment pre-planning 1335 (e.g., any treatment planning activities that may be initiated and / or based on the first-pass data 1315).

[0125] At step 1320, the system performs the second pass of the imaging scan (e.g., while moving the patient support out of the gantry), generating second-pass data 1325. In this embodiment, the system may begin and / or continue processing the first-pass data 1315 generated / received during the first pass 1310 while the system performs the second pass 1320.

[0126] Next, at step 1340, the system may utilize the first-pass data 1315 and / or the second-pass data 1325 (generated / received during the first pass 1310 and the second pass 1320, respectively) to continue various data / image processing and image-based pre-delivery steps (see, for example, Figures 16 - 18 below), including treatment planning (e.g., dose calculation, adaptive planning, etc.). In some embodiments, the system may complete tasks initiated at step 1330 and / or 1335 at step 1340, including, for example, treatment pre-planning 1335 that requires the second-pass data 1325 for final treatment planning 1340.

[0127] In this manner, since image processing and utilization of the first pass data 1315 can occur before and / or during the second pass 1320, and since the time associated with the return of the patient support from within the gantry can be used as the scan time in 1320, the pre-delivery step 1302 can be completed more quickly using multi-pass imaging scanning (relative to single-pass scanning). After the treatment planning 1340 is completed, the process can proceed to treatment delivery at step 1350, including as part of IGRT.

[0128] In one embodiment, the first pass data 1315 has sufficient quality for treatment setup 1330 such that during the second pass 1320, reconstruction and registration of the patient image (based on the first pass data 1315) with previous data is in progress and / or has been completed. After the second pass 1320 is completed, the workflow can proceed directly to treatment planning 1340 based on the first pass data 1315 and the second pass data 1325.

[0129] In other embodiments, the imaging scan consists of more than two passes 1310, 1320. Optional additional (one or more) passes 1312, 1322 and additional associated pass data 1317, 1327 are shown in Figure 13 to represent that the imaging scan in these embodiments can include any number of scan passes at different points in the workflow sequence. Additionally, in various embodiments, the raw and / or processed data from one or more of these passes can be used before or simultaneously with the system performing a subsequent pass to determine / adjust scan parameters associated with the subsequent pass and / or various data / image processing and image-based pre-delivery steps, where the image-based pre-delivery steps include treatment setup 1330 and / or treatment pre-planning 1335. For example, two passes can be performed to generate pass data that can be used to determine scan parameters for a subsequent pass, and then the next pass can generate pass data that is then combined with the previous pass data for treatment setup. As can be appreciated, any number of scan passes can generate pass data that can be used in various combinations for any workflow step.

[0130] Figure 14 is a flowchart of another exemplary multi-pass imaging process 1400. Process 1400 can utilize the imaging system and scan design described above. In this embodiment, the imaging scan includes at least two passes, where each pass acquires a portion of the data required for a full imaging scan. Each pass can be performed more quickly than a full scan. At step 1410, the system performs the first pass of the imaging scan (e.g., while moving the patient support into the gantry), generating first pass data 1415. In this embodiment, the system can utilize the first pass data 1415 generated / received during the first pass 1410 before or simultaneously with the system performing the second pass 1420.

[0131] In this embodiment, before and / or simultaneously with the system performing the second pass 1420, the original and / or processed (e.g., reconstructed) first pass data 1415 is used for treatment setup 1430 (e.g., registering a first patient image (based on the first pass data 1415) with the prior data 1405). Optionally (depicted by the dashed line in Figure 14 ), in some embodiments, the original and / or processed first pass data 1415 may also be used, before the system performs the second pass 1420, to determine / adjust the scan parameters associated with the second pass 1320 (as discussed above).

[0132] In step 1420, the system performs a second pass of the imaging scan (e.g., when moving the patient support out of the gantry), generating second pass data 1425. In this embodiment, the system may start and / or continue treatment setup 1430 using the first pass data 1415 generated / received during the first pass 1410 while the system performs the second pass 1420.

[0133] Next, in step 1440, the system uses the first pass data 1415 and the second pass data 1425 for treatment planning (e.g., dose calculation, adaptive planning, etc.). In some embodiments, the prior data 1405 is also used for the treatment planning 1440 task.

[0134] In this way, since treatment setup 1430 utilizes the first pass data 1415 before and / or during the second pass 1420, and since the time associated with returning the patient support from inside the gantry can be used as the scan time in 1420, the pre-delivery workflow steps of treatment setup 1430 and treatment planning 1440 are completed more quickly using the multi-pass imaging scan (1410 + 1420) than a single-pass scan. After treatment planning 1440 is completed, the process may continue with treatment delivery, including as part of IGRT.

[0135] Figure 15 is a flowchart of another exemplary multi-pass imaging process 1500. Process 1500 may utilize the imaging system and scan design described above. In this embodiment, the imaging scan includes at least two passes, where each pass acquires a portion of the data required for a full imaging scan. Each pass may be performed more quickly than a full scan. In step 1510, the system performs a first pass of the imaging scan (e.g., when moving the patient support into the gantry), generating first pass data 1515. In this embodiment, the system may utilize the first pass data 1515 generated / received during the first pass 1510 before and / or simultaneously with the system performing the second pass 1520.

[0136] In this embodiment, at step 1520, the first-pass data 1515 is reconstructed using a reconstruction technique suitable for the projection data 1515 to generate a patient image 1525. Next, at step 1530, the patient image 1525 is registered with the previous image data 1505 for treatment planning before and / or simultaneously with the system performing the second pass 1540. Optionally (depicted by the dashed line in Figure 15 ), in some embodiments, before the system performs the second pass 1540, the projection data 1515, the patient image 1525, and / or the registered image from 1530 may also be used to determine / adjust the scan parameters associated with the second pass 1540 (as described above).

[0137] At step 1540, the system performs the second pass of the imaging scan (e.g., while moving the patient support out of the gantry), generating second-pass data 1545. In this embodiment, the system may use the first-pass data 1515 generated / received during the first pass 1510 to initiate and / or continue the reconstruction 1520 and / or registration 1530 while the system performs the second pass 1540.

[0138] Next, at step 1550, the system reconstructs the patient image 1555 using the first-pass data 1515 and the second-pass data 1545. At step 1560, the treatment dose is calculated using the patient image 1555. In some embodiments, the previous data 1505 is also used for the dose calculation 1560.

[0139] In this way, since the reconstruction 1520 and registration 1530 steps utilize the first-pass data 1515 before and / or during the second pass 1540, and since the time associated with returning the patient support from inside the gantry can be used as the scan time in 1540, the pre-delivery workflow steps 1520, 1530, 1550, 1560 are completed more quickly using the multi-pass imaging scan (1510 + 1540) than using a single-pass scan. After the dose calculation 1560 is completed, the process may continue to treatment delivery, including as part of IGRT.

[0140] In all of these embodiments, a variety of scan designs can be used, including various designs for procedures including imaging scans. For example, as described above, the patient support 18 can move in a first longitudinal direction (e.g., into the gantry 12) during a first procedure and move in a second longitudinal direction (e.g., out of the gantry 12) during a second procedure, where the second direction is opposite the first direction. However, in other embodiments, different procedures can be in the same direction. The procedures can include different patient support 18 and / or gantry 12 speeds, both of which can be constant or variable. These procedures can also be completed at the same or different times (e.g., where the first procedure is completed in less time than the second procedure). These procedures can also include more or fewer views than other procedures. The procedure trajectory can be helical and / or circular (e.g., step-and-shoot, where a series of steps / shots includes a procedure). The procedure can include periods of time when the imaging radiation source is not activated, including effectively skipping portions of the patient.

[0141] In some embodiments, the axial positions of the imaging radiation source 30 and the detector 34 are shifted between procedures, including cases where data from different procedures are complementary during reconstruction of the patient image. In one embodiment, the detector 34 is offset in one transverse axis direction during a first procedure and in the opposite transverse axis direction during a second procedure, including accommodating a large FOV.

[0142] These techniques can be used for IGRT workflow improvement and optimization as well as CT image quality and quantification improvement for dose calculation and adaptive planning.

[0143] Figure 16is a flowchart depicting an exemplary method 1600 of IGRT using a radiation treatment device (including, for example, an x-ray imaging device 10). Prior data 1605 may include images of the patient (e.g., prior images, which may be previously acquired planning images, including prior CT images, as described above), treatment plans, phantom information, models, prior information, etc. In some embodiments, the prior data 1605 is generated by the same radiation treatment device, but at an earlier time. At step 1610, the patient is imaged (including multi-pass imaging) using a low-energy radiation source (e.g., kV radiation from the x-ray source 30). In various embodiments, the imaging includes a helical or circular scan having a fan or cone geometry. Step 1610 may produce high-quality (HQ) (one or more) images or imaging data 1615 using the techniques described above. In some embodiments, the image quality may be adjusted to optimize the balance between image quality / resolution and dose. In other words, not all images need to have the highest quality, or the image quality may be adjusted to optimize or trade off the balance between image quality / resolution and image acquisition time. The imaging step 1610 may also include image processing 1620 to generate a patient image based on the imaging / scan data 1615 (e.g., according to the embodiments described above). Although the image processing step 1620 is shown as part of the imaging step 1610, in some embodiments, the image processing step 1620 is a separate step, including performing image processing by a separate device.

[0144] Next, at step 1630, one or more image-based pre-delivery steps discussed below are performed, at least in part, based on the imaging data 1615 from step 1610. As discussed in more detail below, step 1630 may include determining various parameters associated with diagnostic treatment and (subsequent) imaging planning. In some embodiments, the image-based pre-delivery step (1630) may require additional imaging (1610) prior to treatment delivery (1640). Step 1630 may include adjusting the treatment plan based on the high-quality imaging data 1615 as part of an adaptive radiation treatment routine. In some embodiments, the image-based pre-delivery step 1630 may include real-time treatment planning. Embodiments may also include simultaneous, overlapping, and / or alternating activation of the imaging and diagnostic radiation sources. Real-time treatment planning may involve any or all of these types of imaging and diagnostic radiation activation techniques (simultaneous, overlapping, and / or alternating).

[0145] Next, at step 1640, a diagnostic treatment delivery is performed using a high-energy radiation source (e.g., MV radiation from the diagnostic radiation source 20). Step 1640 delivers a treatment dose 1645 to the patient according to the treatment plan. In some embodiments, the IGRT method 1600 may include returning to step 1610 for additional imaging at various intervals, followed by image-based pre-delivery steps (1630) and / or treatment delivery (1640) as needed. In this way, high-quality imaging data 1615 can be generated and utilized during IGRT using one device 10 capable of performing adaptive diagnostics. As described above, steps 1610, 1630, and / or 1640 may be performed simultaneously, overlapped, and / or alternately.

[0146] IGRT can include at least two general goals: (i) delivering a highly conformal dose distribution to the target volume; and (ii) delivering the treatment beam with high precision in each treatment fraction. A third goal may be to accomplish the two general goals in as little time as possible per fraction. Precise delivery of the treatment beam requires the ability to use high-quality images to identify and / or track the position of the target volume intrafraction. The ability to increase the delivery speed requires the ability to perform imaging 1610, image-based pre-delivery steps 1630, and treatment delivery 1640 accurately, precisely, and quickly, including moving the radiation source according to the treatment plan.

[0147] The imaging and processing techniques described above that support a faster pre-delivery workflow include multi-pass imaging scans, treatment setup, treatment pre-planning, and treatment planning steps, which are included in the imaging 1610 and image-based delivery pre-transfer steps 1630 described herein, including as part of the IGRT workflow.

[0148] Figure 17 FIG. 1700 is a block diagram depicting an exemplary image-based pre-delivery step / option that may be associated with the above step 1630. It will be understood that the above x-ray imaging device 10 (e.g., as part of a diagnostic device) may generate kV images, which may be used in a variety of ways, including for the image-based pre-delivery step (1630), without departing from the scope of the invention. For example, the image 1615 generated by the diagnostic radiation device may be used to align the patient (1710) prior to treatment. Patient alignment may include correlating or registering the current imaging data 1615 with imaging data associated with an earlier pre-treatment scan and / or plan that includes the treatment plan. Patient alignment may also include feedback regarding the physical position of the patient relative to the radiation source to verify that the patient is physically within the range of the delivery system. If needed, the patient may be adjusted accordingly. In some embodiments, the patient alignment imaging may deliberately have lower quality to minimize dose, but provide sufficient alignment information.

[0149] The images generated by the x-ray imaging device 10 can also be used for treatment planning or replanning (1720). In various embodiments, step 1720 may include validating a treatment plan, modifying a treatment plan, generating a new treatment plan, and / or selecting a treatment plan from a set of treatment plans (sometimes referred to as a "same-day plan"). For example, if the imaging data 1615 shows that the target volume or ROI is the same as when the treatment plan was developed, the treatment plan can be validated. However, if the target volume or ROI is not the same, a re-planning of the diagnostic treatment may be required. In the case of re-planning, due to the high quality of the imaging data 1615 (generated by the x-ray imaging device 10 in step 1610), the imaging data 1615 can be used for treatment planning or replanning (e.g., generating a new or modified treatment plan). In this way, pre-treatment CT imaging via a different device is not required. In some embodiments, validation and / or re-planning can be an ongoing process before and / or after various treatments.

[0150] According to another exemplary use case, the images generated by the x-ray imaging device 10 can be used to calculate the imaging dose (1730), which can be used for the ongoing determination of the total dose to the patient and / or for subsequent imaging planning. The quality of subsequent imaging can also be determined as part of the treatment planning, e.g., to balance quality and dose. According to another exemplary use case, the images generated by the x-ray imaging device 10 can be used to calculate the treatment dose (1740), which can be used for the ongoing determination of the total dose to the patient and / or can be included as part of a treatment plan or replanning.

[0151] According to other exemplary use cases, the images generated by the x-ray imaging device 10 can be used in combination with planning or adjusting other imaging (1750) and / or other treatment (1760) parameters or plans, including, for example, as part of an adaptive diagnostic and / or treatment plan generation. According to another exemplary use case, the images generated by the x-ray imaging device 10 can be used in combination with adaptive diagnostic monitoring (1770), which can include monitoring treatment delivery and adapting as needed.

[0152] It should be understood that the image-based pre-delivery steps (1630) are not mutually exclusive. For example, in various embodiments, calculating the treatment dose (1740) can be a separate step and / or can be part of the adaptive diagnostic monitoring (1770) and / or treatment planning (1720). In various embodiments, the image-based pre-delivery steps (1620) can be performed automatically and / or manually with human participation.

[0153] The above-described devices and methods including an offset detector and data processing techniques can provide improved kV-generated images with higher quality than those of imaging systems in conventional therapies.

[0154] Figure 18 FIG. 1800 is a block diagram depicting exemplary data sources that can be utilized during imaging (1610) and / or subsequent image-based pre-delivery steps (1630). Detector data 1810 represents all data received by the image radiation detector 34. Projection data 1820 is data generated by radiation incident on the collimated beam region. Penumbra data 1830 is data generated by radiation incident on the penumbra region. Scatter data 1840 is data generated by radiation incident on the peripheral region outside the penumbra region, which may be referred to as the (one or more) shadow regions.

[0155] In one embodiment, the penumbra data 1830 can be used to separate or identify projection and / or scatter data. In some embodiments, the scatter data 1840 can be used to estimate scattered radiation in the projection data 1820. In another embodiment, when two sources 20, 30 are operated simultaneously or in an interleaved manner, the scatter data 1840 can be used to determine the residual effects of scatter from the therapeutic radiation source 20 (e.g., MV).

[0156] In this manner, the penumbra data 1830 and / or the scatter data 1840 can be utilized to improve the quality of the images generated by the imaging step 1610. In some embodiments, the penumbra data 1830 and / or the scatter data 1840 can be combined with the projection data 1820 and / or analyzed in view of applicable imaging settings 1850, treatment settings 1860 (e.g., if imaging and therapeutic radiation are simultaneous), and any other data 1870 associated with the x-ray imaging device 10 when collecting data at the imaging detector 34. In other embodiments, the data can be used for the treatment planning step 1630.

[0157] Although the disclosed technology has been shown and described with respect to specific aspects, embodiments, or multiple embodiments, it is apparent that equivalent changes and modifications will occur to those skilled in the art upon reading and understanding this specification and the drawings. In particular, with respect to the various functions performed by the above-described elements (components, assemblies, devices, members, compositions, etc.), unless otherwise indicated, the terms used to describe these elements (including references to "means") are intended to correspond to any element that performs the specified function of the described element (i.e., functionally equivalent), even if structurally not equivalent to the disclosed structure that performs the function in the exemplary aspects, one or more embodiments of the technology disclosed herein. Additionally, although a particular feature of the disclosed technology may have been described above with respect to only one or more of several illustrated aspects or embodiments, this feature may be combined with one or more other features of other embodiments, as may be desired and advantageous for any given or particular application.

[0158] While the embodiments discussed herein relate to the systems and methods discussed above, these embodiments are intended to be exemplary and are not intended to limit the applicability of these embodiments to only those discussions set forth herein. Although the present invention has been illustrated by the description of the embodiments of the present invention and although the embodiments have been described in considerable detail, the intention of the applicant is not to limit or in any way restrict the scope of the appended claims to such details. Additional advantages and modifications will readily occur to those skilled in the art. Thus, the present invention in its broader aspects is not limited to the specific details, representative devices and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's general inventive concept.

Claims

1. An x-ray imaging device for multi-pass scanning, comprising: A rotatable gantry system that is positioned at least partially around a patient support; A first radiation source coupled to the rotatable gantry system, the first radiation source being configured as an imaging radiation source; A radiation detector coupled to the rotatable gantry system and positioned to receive radiation from the first radiation source during an imaging scan; A controller configured to: Move the patient support relative to the rotatable gantry system during a first pass of the imaging scan; Move the patient support relative to the rotatable gantry system during a second pass of the imaging scan; A data processing system configured to: Receive first imaging data measured by the radiation detector during the first pass; Receive second imaging data measured by the radiation detector during the second pass; Combine the first imaging data and the second imaging data into a combined imaging data set; and Use the combined imaging data set to reconstruct a second patient image; Wherein the relative axial position of the first radiation source and the radiation detector is shifted during the second pass relative to the first pass, and wherein the first imaging data and the second imaging data are jointly used during the reconstruction of the second patient image.

2. The device according to claim 1, wherein the data processing system is further configured to reconstruct a first patient image based on the first imaging data, wherein the first patient image is reconstructed during the second pass.

3. The device according to claim 1, wherein the scan parameters for the second pass are determined based on the first imaging data.

4. The device according to claim 3, wherein the data processing system is further configured to reconstruct a first patient image based on the first imaging data, and wherein the first patient image is registered with a planning image to determine the scan parameters.

5. The device according to claim 3, wherein the scan parameters include at least one of the following: pitch, energy level, tube potential, tube current, pulse width, beam filter, or speed.

6. The device according to claim 1, wherein the first pass includes a first tube energy of the first radiation source, and the second pass includes a second tube energy of the first radiation source, and wherein the second patient image includes a spectral patient image.

7. The device according to claim 1, wherein the data processing system is further configured to reconstruct a first patient image based on the first imaging data, wherein the first patient image and the second patient image are used for image-based pre-delivery steps, wherein the pre-delivery steps include treatment setup and treatment planning, and wherein the treatment setup is based on the first patient image, and the treatment planning is based on the second patient image.

8. The device according to claim 7, wherein the treatment setup includes registering the first patient image with a planning image.

9. The device according to claim 1, wherein the patient support moves in a first longitudinal direction during the first pass and in a second longitudinal direction during the second pass, and wherein the second longitudinal direction is opposite to the first longitudinal direction.

10. The device according to claim 1, wherein the patient support moves at a first speed during the first pass and at a second speed during the second pass, and wherein the first speed is faster than the second speed.

11. The device according to claim 1, wherein the first pass and the second pass comprise helical scans.

12. The device according to claim 1, wherein the first pass is completed within a first time and the second pass is completed within a second time, and wherein the second time is longer than the first time.

13. The device according to claim 1, wherein the second pass comprises more views than the first pass.

14. The device according to claim 1, wherein the radiation detector is offset in one transverse axis direction during the first pass and in the opposite transverse axis direction during the second pass.

15. The device according to claim 1, further comprising a second radiation source coupled to the rotatable gantry system, the second radiation source being configured as a treatment radiation source, wherein the second radiation source delivers a dose of radiation calculated based on a second patient image.

16. A method of collecting imaging data during a multi-pass scan, comprising: Moving a patient support relative to a rotatable gantry system during a first pass of an imaging scan, wherein a first radiation source and a radiation detector are coupled to the rotatable gantry system, the rotatable gantry system being positioned at least partially around the patient support; Receiving first imaging data measured by the radiation detector during the first pass; Moving the patient support relative to the rotatable gantry system during a second pass of the imaging scan; Receiving second imaging data measured by the radiation detector during the second pass; Combining the first imaging data and the second imaging data into a combined imaging data set; and Using the combined imaging data set to reconstruct a second patient image; Reconstructing a first patient image based on the first imaging data; Registering the first patient image with a planning image for treatment setup; and Calculating a treatment radiation dose based on the second patient image.

17. The method according to claim 16, wherein the patient support moves in a first longitudinal direction during the first pass and in a second longitudinal direction during the second pass, and wherein the second longitudinal direction is opposite to the first longitudinal direction.

18. A radiation treatment delivery device, comprising: A rotatable gantry system positioned at least partially around a patient support; A first radiation source coupled to the rotatable gantry system, the first radiation source being configured as an imaging radiation source; A second radiation source coupled to the rotatable gantry system, the second radiation source being configured as a treatment radiation source; A radiation detector, which is coupled to the rotatable gantry system and is positioned to receive radiation from the first radiation source during an imaging scan; A controller, which is configured to: Move the patient support relative to the rotatable gantry system during a first leg of the imaging scan; Move the patient support relative to the rotatable gantry system during a second leg of the imaging scan; A data processing system, which is configured to: Receive first projection data measured by the radiation detector during the first leg; Reconstruct a first patient image based on the first projection data; Receive second projection data measured by the radiation detector during the second leg; And Reconstruct a second patient image based on the first projection data and the second projection data; wherein a treatment setup is based on the first patient image, and wherein the second radiation source delivers a dose of radiation calculated based on the second patient image during adaptive IGRT.

Images