Restriction of Imaging Radiation Dose and Improvement of Image Quality during Therapy Delivery

Abstract

To provide systems for minimizing the exposure to additional radiation by adjusting a field of view of a kV imaging source with a collimator.SOLUTION: A method includes imaging a first field of view (FOV) of a volume of interest (VOI) that includes a region of interest (ROI) from a first position, and imaging the first FOV of the VOI from a second position. The method includes receiving first identification information of a first portion of the imaged VOI designating the ROI to be imaged and second identification information of a second portion of the imaged VOI from the second position designating the ROI to be imaged. The method includes, in response to the first identification information, adjusting an aperture of a collimator of an imaging source to a second FOV corresponding to the ROI from the first position, and imaging the ROI using the second FOV. The method includes, in response to the second identification information, adjusting the aperture of the collimator to a third FOV corresponding to the ROI from the second position, and imaging the ROI using the third FOV.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] (Related Application) This application claims priority under 35 U.S.C. § 119(e) to U.S. Patent Application No. 15 / 922,688, filed March 15, 2018, entitled "Limiting Imaging Radiation Dose and Improving Image Quality During Therapy Delivery," the entire content of which is incorporated herein by reference.

[0002] Embodiments of the present disclosure relate to the field of radiation therapy delivery imaging.

Background Art

[0003] Intra-fraction tumor motion during radiation therapy treatment is a problem in recent image-guided radiation therapy. Providers of radiation oncology treatment systems have incorporated kV x-ray imaging systems to acquire 2D x-ray images of the radiation target and provide real-time information regarding tumor position. This information can be used by the treatment system to modify the delivery of the treatment dose and compensate for tumor motion.

[0004] In parallel with these developments, attention has come to be paid to the radiation dose absorbed by a patient from medical imaging techniques. Use of an x-ray imaging system in a radiation therapy technique increases the radiation dose absorbed by the patient.

Summary of the Invention

Means for Solving the Problems

[0005] In one embodiment, the apparatus comprises an x-ray imaging source of a helical delivery system, the x-ray imaging source including a variable aperture collimator. The collimator can comprise a multi-leaf collimator. Alternatively, the collimator can comprise an iris collimator.

[0006] In one embodiment, the method includes receiving an image from a treatment planning system having a volume of interest (VOI) that includes a region of interest (ROI) of a patient, and in response to receiving the image from the treatment planning system, adjusting an aperture of an x-ray imaging source to a first field of view (FOV) corresponding to the VOI. The method also includes imaging the first FOV of the VOI that includes the patient's ROI with an x-ray imager. The method also includes receiving identification information of the imaged VOI that designates the ROI to be imaged, and in response to receiving the identification information, adjusting an aperture of a collimator of the x-ray imaging source to a second FOV corresponding to the ROI, the second FOV being different from the first FOV. The method also includes imaging the patient's ROI using the second FOV. The method further includes receiving a setup image having a VOI that includes the patient's ROI, and in response to receiving the setup image, adjusting an aperture of a collimator of the x-ray imaging source to a third FOV corresponding to a portion of the VOI, and imaging the third FOV of the portion of the VOI that includes the patient's ROI.

[0007] In one embodiment, the method includes generating a pre-diagnosis (or pre-setup) scan of a volume of interest (VOI) that includes a region of interest (ROI) of a patient, and in response to receiving the pre-diagnosis scan, adjusting an aperture of a collimator of an x-ray imaging source to a first field of view (FOV) corresponding to the VOI. The method also includes imaging the first FOV of the VOI that includes the patient's ROI with an x-ray imager, and receiving second identification information of a first portion and a second portion of the imaged VOI that designates the ROI to be imaged. In response to receiving the second identification information, the method also includes adjusting an aperture of a collimator of the x-ray imaging source to a second FOV corresponding to the ROI and different from the first FOV, and imaging the patient's ROI using the second FOV.

[0008] In one embodiment, the method includes imaging a first field of view (FOV) of a volume of interest (VOI) including a region of interest (ROI) of a patient from a first position by a first X-ray imager including a first X-ray imaging source, and imaging a second FOV of a VOI including the ROI of the patient from a second position by a second X-ray imager including a second X-ray imaging source. The method also includes receiving first identification information of a first portion of the imaged VOI from the first position that designates the imaged ROI, and receiving second identification information of a second portion of the imaged VOI from the second position that designates the imaged ROI. The method also includes, in response to receiving the first identification information, adjusting an aperture of a collimator of the first X-ray imaging source to a third FOV corresponding to the ROI from the first position, different from the first FOV from the first position, and imaging the ROI of the patient from the first position using the third FOV. The method also includes, in response to receiving the second identification information, adjusting an aperture of a collimator of the second X-ray imaging source to a fourth FOV corresponding to the ROI from the second position, different from the second FOV from the second position, and imaging the ROI of the patient from the second position using the fourth FOV.

[0009] Embodiments of the present disclosure are shown by way of illustration and not limitation in the figures of the accompanying drawings.

Brief Description of the Drawings

[0010]

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DETAILED DESCRIPTION OF THE INVENTION

[0011] To control a radiotherapy technique, the position of a target region (e.g., a tumor) to be treated can be tracked using a kilovolt (kV) x-ray imaging system. This can be particularly important for targets that may move during treatment, such as targets in or near the lungs, heart, prostate, or other target regions. In some types of target regions, existing techniques for tracking the target region may not be optimal due to additional radiation exposure to the patient. For example, some target regions may require an increase in the energy of the imaging x-ray beam to obtain an x-ray image that can be used to expose the patient to a large amount of radiation. In another example, to accurately treat a target region that is moving within a patient, x-ray images of the target region may be generated at a frequency sufficient to verify the position of the target region, exposing the patient to additional radiation. Embodiments of the present disclosure relate to methods and systems for generating and using images of smaller regions of interest (ROIs) within a treatment volume of interest (VOI) of a patient during radiotherapy delivery to minimize the patient's exposure to additional radiation.

[0012] During treatment delivery, dynamic tracking of the ROI can be performed based on the use of x-ray images taken to identify the target region. Once the position of the target region is computed by a computer, the treatment delivery (e.g., the position of the radiation beam source of a radiotherapy delivery system) can be adjusted to compensate for the dynamic movement of the target. To accurately track the movement of the target region, x-ray images of the target within the patient can be continuously generated throughout the treatment using an x-ray imaging system. However, as a result, the patient may be exposed to additional radiation.

[0013] One embodiment of the present disclosure can minimize the above-mentioned additional radiation exposure problem by adjusting the field of view (FOV) of a kV imaging source to a smaller field of view with respect to a specific region of interest (ROI) around a treatment target by means of a collimator. For example, based on the identification information of the ROI in the full FOV of an X-ray imaging system, the aperture of the collimator of the kV imaging source can be adjusted to correspond to the size or shape of the ROI, thereby producing an X-ray image of the ROI that can have a smaller FOV than, for example, the full FOV X-ray image generated during the patient setup phase. This enables the generation of an X-ray image of the ROI that has the same or better quality as the X-ray image with the full FOV without exposing the healthy tissue surrounding the ROI to unwanted radiation, and can reduce the overall image radiation dose to the patient. In other words, the embodiments of the present disclosure can reduce the amount of tissue irradiated, thereby reducing scatter and thus improving the image quality of the reduced FOV imaged relative to the image quality of the region with a larger FOV (e.g., not collimated).

[0014] Note that in some embodiments described below, the same radiation source can be used to provide both high-energy therapeutic radiation and low-energy imaging radiation. In such embodiments, the radiation source can be a linear accelerator (LINAC) having a primary collimator and a secondary collimator. The primary collimator can have a fixed aperture and is positioned after the electron beam passes through the X-ray emission target. The secondary collimator can be positioned after the primary collimator and can have a variable aperture, as will be described in detail below.

[0015] Embodiments of the present disclosure are particularly applicable to radiosurgical treatment systems and methods, and in this context, these embodiments of the present disclosure will be described. However, it will be understood that the systems and methods according to the present disclosure have excellent utility for other types of treatments that require accurately positioning treatment at a target region within a patient in order to avoid damage to healthy tissue, such as other types of medical procedures using other types of medical devices.

[0016] Figure 1 shows a helical delivery system 100 according to an embodiment of the present disclosure. The helical delivery system 100 of FIG. 1 can include a linear accelerator (LINAC) 110 mounted on a ring gantry 120. By orienting an electron beam towards an X-ray emission target using the LINAC 110, a narrow intensity-modulated pencil beam (i.e., a treatment beam) can be generated. This treatment beam can deliver radiation to a target region (i.e., a tumor). The ring gantry 120 generally has a toroidal shape, within which the patient 130 extends through the bore of the ring / torus, with the LINAC 110 mounted on the outer periphery of the ring and rotating about an axis passing through the center to irradiate the target region with the beam being irradiated from one or more angles around the patient. During treatment, the patient 130 can simultaneously move through the bore of the gantry on a treatment couch 140.

[0017] The helical delivery system 100 of FIG. 1 includes a therapeutic imaging system that can include a kV imaging source 150 and an x-ray detector 170. Using the kV imaging source 150, an x-ray image of the ROI of the patient 130 can be generated by orienting a sequence of x-ray beams incident on the x-ray detector 170 on the opposite side of the kV imaging source 150 in the ROI and imaging the patient 130 in the setup to generate an in-treatment image. The therapeutic imaging system can further include a collimator 160. In one embodiment, the collimator 160 can be a variable aperture collimator as described in FIG. 7. In another embodiment, the collimator 160 can be a multi-leaf collimator (MLC). The MLC includes a housing that houses a plurality of leaves that are movable to adjust the aperture of the MLC to enable shaping of the imaging x-ray beam. In another embodiment, the variable aperture collimator 160 can be an iris collimator that includes a trapezoidal block that moves along a frame in a manner similar to a camera iris to generate a variable size aperture to enable shaping of the imaging x-ray beam. The kV imaging source 150 and the x-ray detector 170 can be mounted on the ring gantry 120 at right angles (e.g., separated by 90 degrees) to the LINAC 110 and can be positioned to illuminate the imaging surface of the detector 170 after projecting the imaging x-ray beam through the patient 130 at the target region. In some embodiments, the LINAC 110 and / or the kV imaging source 150 can be mounted in a cantilever-like fashion on a C-arm gantry that rotates the LINAC 110 and the kV imaging source 150 about an axis passing through the isocenter.

[0018] In one embodiment, the radiation therapy system 100 can include a motion detection device 180 that determines the movement of the target. The motion detection device 180 can detect the movement of the outer patient occurring within the imaging field (such as the movement of the chest during breathing). The motion detection device 180 can be any sensor or other device that can identify the movement of the target. The motion detection device 180 can be, for example, an optical sensor such as a camera, a pressure sensor, an electromagnetic sensor, or any other sensor (such as a sensor other than an X-ray imaging system) that can provide motion detection without delivering ionizing radiation to the patient 130. In one embodiment, the motion detection device 180 acquires measurement data indicating the movement of the target in real time. Alternatively, the measurement data can be acquired at a higher (possibly much higher) or more frequent rate than can be achieved by X-ray imaging (due to the ionizing radiation delivered to the patient 130 by each X-ray image). In one embodiment, the motion detection device 180 does not provide high absolute position accuracy. Instead, the motion detection device 180 can provide sufficient relative position accuracy to detect the movement of the patient and / or the movement of the target.

[0019] In one embodiment, the motion detection device 180 is an optical system such as a camera. The optical system can track the position of a light-emitting diode (LED) 190 located on the patient 130. Alternatively, the optical system can directly track the surface area (such as the skin surface) of the patient 130, which is distinguishable from the tracking of the LED 190 of the patient 130. A correlation relationship can exist between the movement of the target area described in detail in FIGS. 3-6 below and the movement of the LED and / or the surface area of the patient 130. A correlation model can be generated between the position of the target area and the tracked LED 190 and / or the surface area of the patient 130 to predict the position of the target area at a subsequent time point. Based on this prediction, the aperture of the collimator 160 of the kV imaging source 150 can be adjusted to correspond to the predicted position of the target area. The adjustment of the aperture of the collimator 160 will be described in detail in FIG. 7 below.

[0020] Figure 2 is a cross-section 200 of the treatment imaging system of FIG. 1. As described above, the kV imaging source 150 projects an imaging X-ray beam 210 through the bore 220 of the treatment system that illuminates the imaging surface of the X-ray detector 170 after passing through the patient. The kV imaging source 150 and the X-ray detector 170 can rotate along the circular track 230 of the ring gantry 120 around the bore 220 of the treatment system to generate X-ray images of the target region from a plurality of angles.

[0021] Figure 3 is a flowchart 300 showing a method for adjusting the aperture of the collimator of the kV imaging source to image a target region according to an embodiment of the present disclosure. The method of FIG. 3 enables identification information of a ROI including the target region from the full FOV image of the VOI. Using this identification information, the treatment imaging system adjusts the aperture of the collimator 160 to correspond to the identified ROI, minimizing the radiation exposure of the tissue surrounding the ROI. In block 302, the kV imaging source 150 and the X-ray detector 170 generate an image of the patient's VOI including the target region from a first angle. In block 304, after generating the X-ray image of the patient's VOI from the first angle, the kV imaging source 150 and the X-ray detector 170 can rotate to a second angle. In block 306, the kV imaging source 150 and the X-ray detector 170 generate an image of the patient's VOI including the target region from the second angle. In some embodiments, the first angle and the second angle can be determined prior to treatment using a treatment planning system. The image of the VOI can be captured in the full FOV, where the collimator device may not shape the imaging X-ray beam. In some embodiments, the ROI including the target region can be identified during the treatment planning phase, and the image of the VOI can be captured in a partial FOV corresponding to the ROI identified during the treatment planning.

[0022] In block 308, the treatment imaging system receives identification information of an ROI that includes the target region in the VOI image generated in block 302. In some embodiments, the target region can be identified by the user selecting the target region from the generated image. In other embodiments, the target region can be identified by the treatment imaging system using image recognition software or the like. In block 310, the treatment imaging system receives identification information of an ROI that includes the target region in the VOI image generated in block 306. The target region can be identified using a method similar to the method described in block 308. In block 312, the aperture of the collimator 160 of the kV imaging source 150 can be adjusted using the method described above to correspond to the ROI identified in block 308. Adjustment of the aperture can enable the kV imaging source 150 and the x-ray detector 170 to generate an image having a partial FOV smaller than the FOV in block 302. In block 314, the kV imaging source 150 and the x-ray detector 170 generate an image having a partial FOV of the ROI from a first angle, and the resulting image can correspond to the ROI identified in block 308. In block 316, after generating an x-ray image of the patient's ROI from a first angle, the kV imaging source 150 and the x-ray detector 170 can rotate to a second angle. In block 318, the aperture of the collimator 160 of the kV imaging source 150 can be adjusted using the method described above to correspond to the ROI identified in block 310. Adjustment of the aperture can enable the kV imaging source 150 and the x-ray detector 170 to generate an image having a partial FOV smaller than the FOV in block 306. In block 320, the kV imaging source 150 and the x-ray detector 170 generate an image having a partial FOV of the ROI from a second angle, and the resulting image can correspond to the ROI identified in block 310. Embodiments of the present invention describe imaging of an ROI having a partial FOV to reduce the radiation dose delivered to the patient 130.However, the actual tracking of the target region is used in conjunction with other techniques that use external markers attached to patient 130, and the movement of the external markers can be correlated with the movement of the target region. An example of one such system is the Synchrony™ breathing tracking system developed by Accuray.

[0023] FIG. 4 is a diagram 400 that generates an x-ray image having a full FOV from a first angle. The diagram shown in FIG. 4 can represent block 302 of the method of FIG. 3 according to an embodiment of the present disclosure. The kV imaging source 150 and the x-ray detector 170 generate an imaging x-ray beam 410 having a full FOV of the VOI of patient 130 that includes the target region 420 from a first angle. The imaging x-ray beam 410 passes through patient 130 and the target region 420 and is incident on the x-ray detector 170. The imaging x-ray beam 410 illuminates the imaging surface of the x-ray detector 170 after passing through patient 130, and this can be used by the treatment imaging system to generate an x-ray image of the VOI that includes the target region 420 at a first position from a first angle. When the x-ray image of the VOI from the first angle is acquired, the kV imaging source 150 and the x-ray detector 170 can be rotated along the circular track 230 to a second angle as described above in block 304.

[0024] When the kV imaging source 150 and the x-ray detector 170 reach the second angular position, an image can be generated that covers the full FOV of the VOI. The diagram 500 shown in FIG. 5 can represent block 306 of the method of FIG. 3 according to an embodiment of the present disclosure. The kV imaging source 150 and the x-ray detector 170 generate an imaging x-ray beam 510 having a full FOV of the VOI of patient 130 that includes the target region 420 from a second angle. The imaging x-ray beam 510 passes through patient 130 and the target region 420 and is incident on the x-ray detector 170. The imaging x-ray beam 510 illuminates the imaging surface of the x-ray detector 170 after passing through patient 130, and this can be used by the treatment imaging system to generate an x-ray image of the VOI that includes the target region 420 from a second angle.

[0025] FIG. 6A is a diagram of identification information of a region of interest (ROI) in the X-ray image generated in FIG. 4. The generated X-ray image 600 of the VOI from the first angle can include a target region 420 and an internal reference structure 620 positioned near the target region 420. In the illustrated embodiment, the internal reference structure 620 can be a fiducial marker embedded within or near the target region 420 and visible in the X-ray image 600. In another embodiment, the internal reference structure 620 can be a bone of the patient 130 positioned adjacent to the target region 420. In some embodiments, it can be possible to generate a visible X-ray image of the target region 420 and also perform direct target imaging of the target region 420. Then, the treatment system can receive identification information of the ROI 610 from the first angle, including the target region 420. As described above, in some embodiments, the identification information of the ROI can be based on the user's selection of the ROI. The user's selection of the ROI can be completed by the user selecting the ROI from the user interface of the helical delivery system. In other embodiments, the ROI can be automatically identified by the helical delivery system using image recognition software or the like. In other embodiments, the selection of the ROI can be received from a treatment planning system or a pre-diagnostic scan.

[0026] FIG. 6B is a diagram of identification information of the ROI in the X-ray image generated in FIG. 5. The generated X-ray image 620 of the VOI from the second angle can include the target region 420 and the VOI surrounding the target region. Then, the treatment system can receive identification information of the ROI 630 from the second angle, including the target region 420. The identification information of the ROI 630 can be completed using a method similar to the method described in FIG. 6A.

[0027] FIG. 7 is FIG. 700 of the collimator 160 of FIG. 1 according to an embodiment of the present disclosure. In one embodiment, the collimator 160 can be a variable aperture collimator. The aperture 750 of the collimator 160 of the kV imaging source 150 can be adjusted as described above with respect to block 312 and block 318 of FIG. 3. The size and / or shape of the aperture can be adjusted to correspond to the ROI identified in FIGS. 6A and 6B. The collimator 160 can be composed of a series of plates 710, 720, 730, 740, where the positioning of the plates creates an aperture 750 at the center of the plates. The imaging X-ray beam passes through the aperture 750, and the shape of the imaging X-ray beam can correspond to the shape of the aperture 750. Thus, the size and shape of the X-ray beam can be adjusted by changing the size and shape of the aperture 750 by moving the plates 710, 720, 730, 740 within the collimator 160. The plates 710, 720, 730, 740 can be made of a material that blocks the passage of radiation, such as lead. Plates 710 and 720 can be positioned on parallel planes within the collimator 160 and can move vertically independently of each other along the longitudinal axis. Plates 730 and 740 can be positioned on parallel planes within the collimator 160 and can move horizontally independently of each other along the transverse axis. In some embodiments, the plates 710, 720, 730, 740 can be moved by a series of actuators coupled to the plates 710, 720, 730, 740 that can extend or contract. In another embodiment, the plates can be manually moved by sliding the plates along the transverse or longitudinal axis by the user and fixing the plates 710, 720, 730, 740 in place with fasteners. Thus, the aperture 750 and the X-ray beam can be adjusted to various rectangular shapes having various sizes. As described above, in some embodiments, the collimator 160 can be a variable aperture collimator that includes a trapezoidal block that moves along a frame in a manner similar to a camera iris to produce a variable size aperture that enables shaping of the imaging X-ray beam.

[0028] FIG. 8 is a diagram 800 that generates an x-ray image having a partial FOV from a first angle. The diagram shown in FIG. 8 can represent block 314 of the method of FIG. 3, according to an embodiment of the present disclosure. Prior to imaging, the collimator 160 can adjust the aperture to correspond to the ROI identified in FIG. 6A using the method described in FIG. 7 and can create a partial FOV for the kV imaging source 150. The kV imaging source 150 can then generate an imaging x-ray beam 810 having a partial FOV of the ROI of the patient 130 that includes the target region 420 from a first angle. The imaging x-ray beam 810 passes through the patient 130 and the target region 420 and is incident on the x-ray detector 170. The imaging x-ray beam 810 illuminates the imaging surface of the x-ray detector 170 after passing through the patient 130, and the treatment imaging system can use this to generate an x-ray image of the ROI that includes the target region 420 from a first angle. When the x-ray image of the ROI from the first angle is acquired, the kV imaging source 150 and the x-ray detector 170 can rotate along the circular track 230 to a second angle.

[0029] When the kV imaging source 150 and the X-ray detector 170 reach the second angle, an image can be generated that covers the partial FOV of the ROI from the second angle. FIG. 900 shown in FIG. 9 can represent block 320 of the method of FIG. 3 according to an embodiment of the present disclosure. Prior to imaging, the collimator 160 can adjust the aperture to correspond to the ROI identified in FIG. 6B using the method described in FIG. 7 and create a partial FOV for the kV imaging source 150. Next, the kV imaging source 150 and the X-ray detector 170 can generate an imaging X-ray beam 910 having a partial FOV of the ROI of the patient 130 that includes the target region 420 from the second angle. The imaging X-ray beam 910 passes through the patient 130 and the target region 420 and is collected by the X-ray detector 170. The imaging X-ray beam 810 illuminates the imaging surface of the X-ray detector 170 after passing through the patient 130, and the treatment imaging system can use this to generate an X-ray image of the ROI that includes the target region 420 from the first angle. When the X-ray image of the ROI from the first angle is acquired, the kV imaging source 150 and the X-ray detector 170 can rotate along the circular track 230 back to the first angle, where the imaging sequence can be repeated.

[0030] FIG. 10 is a diagram 1000 of a method for adjusting the aperture of the collimator of the kV imaging source 150 while the kV imaging source 150 rotates from a first angle to a second angle. The kV imaging source 150 can be positioned at a first angle 1010 and can generate an imaging x-ray beam 810 having a FOV 1020 to image the ROI as shown in FIG. 8. After the x-ray image is captured, the kV imaging source 150 and the x-ray detector 170 can begin to rotate to the second angle. As the kV imager rotates towards the second angle, the aperture of the collimator of the kV imaging source 150 can begin to be adjusted according to the method described above. In one embodiment, at an angle 1030, the kV imager can be assumed to be in the process of rotation between the first angle and the second angle. The aperture of the collimator of the kV imaging source 150 can be adjusted to reduce the FOV 1050 with respect to the FOV 1020 at the first angle 1010. In another embodiment, when the kV imager reaches the second angle, the aperture of the collimator of the kV imaging source 150 can be adjusted. When the kV imager reaches the second angle 1060, the adjustment of the aperture of the collimator of the kV imaging source 150 to correspond to the ROI identified in FIG. 6B can be completed. The kV imager can then generate an imaging x-ray beam 910 having a FOV 1070 to image the ROI as shown in FIG. 9.

[0031] FIG. 11A is FIG. 1100 of the X-ray image from the first angle generated in FIG. 8. The X-ray image 1110 can correspond to the ROI identified in FIG. 6A and can include the target region 420 of the patient 130 from the first angle. FIG. 11B is FIG. 1120 of the X-ray image from the second angle generated in FIG. 9. The X-ray image 1130 can correspond to the ROI identified in FIG. 6B and can include the target region 420 of the patient 130 from the second angle. In some embodiments, the imaging sequence can be repeated during the treatment session using the ROI identified in FIGS. 6A and 6B. In other embodiments, the treatment imaging system can receive identification information of a new ROI in the X-ray images of FIGS. 11A and 11B using the method described above and can start a new imaging sequence.

[0032] FIG. 12 shows the configuration of an image-guided radiation therapy (IGRT) system 1200 capable of implementing an embodiment of the present disclosure. The IGRT system 1200 can include kV imaging sources 1202A and 1202B, which can be mounted on tracks 1222A and 1222B on the ceiling 1220 of the operating room and aligned to project imaging X-ray beams 1204A and 1204B from two different positions. As a result, the radiation 1212A of beam 1204A intersects the radiation 1212B of beam 1204B at the imaging center 1226 (i.e., the isocenter), providing a reference point for positioning the LINAC 1208 for generating treatment beams 1216A, 1216B, and 1216C and the patient 1210 on the treatment couch 1214 during treatment. After passing through the patient 1210, the imaging X-ray beams 1204A and 1204B can illuminate the respective imaging surfaces of X-ray detectors 1224A and 1224B that can be mounted substantially parallel to each other (e.g., within 5 degrees) near or on the floor 1218 of the operating room. The kV imaging sources 1202A and 1202B can be in substantially the same plane such that the imaging surfaces of the kV imaging sources 1202A and 1202B form a single imaging plane. In one embodiment, the kV imaging sources 1202A and 1202B can be replaced with a single kV imaging source. When an X-ray image of the patient 1214 is generated, the LINAC 1208 can rotate to generate treatment beams 1216 from different angles. While the LINAC 1208 rotates to different angles, the kV imaging sources 1202A and 1202B can move along the tracks 1222A and 1222B to generate X-ray images of the patient 1210 from new angles.

[0033] In some embodiments, the kV imaging source and the LINAC can be used in other types of gantry-based systems, such as the TrueBeam™ radiation therapy system manufactured by Varian Medical Systems shown in FIG. 13. The radiation therapy system 1300 can include a LINAC 1310 mounted on a C-arm gantry 1320 that rotates about an axis passing through the isocenter. The radiation therapy system can also include a treatment imaging system composed of a kV imaging source 1330 and an X-ray detector 1340. The kV imaging source 1330 having a variable aperture collimator and an X-ray detector 1340 is mounted on a robotic arm positioned on opposite sides of the isocenter of the C-arm gantry 1320 to enable imaging of the patient's VOI on the treatment couch 1350.

[0034] Embodiments of the present disclosure can be implemented in a portal imaging system 1400 as shown in FIG. 14. In the portal imaging system 1400, the beam energy of the LINAC can be adjusted during treatment to enable the use of the LINAC for both X-ray imaging and radiation therapy. The gantry-based radiation system 1400 includes a gantry 1410, a radiation source 1420 (i.e., LINAC), and a portal imaging device 1450. The gantry 1410 can be rotated to an angle corresponding to a selected projection and used to acquire an X-ray image of the patient's 1430 VOI on the treatment couch 1440. The radiation source 1420 can then generate an X-ray beam passing through the patient's 1430 VOI and incident on the portal imaging device 1450 to generate an X-ray image of the VOI. After the X-ray image of the VOI is generated, the beam energy of the radiation source 1420 is increased, whereby the radiation source 1420 can generate a treatment beam for treating the target region of the patient 1430.

[0035] Alternatively, the kV imaging source and operating method described herein can also be used in other types of gantry-based systems. In some gantry-based systems, the gantry rotates the kV imaging source and the LINAC around an axis passing through the isocenter. The gantry-based system includes a ring gantry having a generally toroidal shape in which the patient's body extends through the bore of the ring / torus, and the kV imaging source and the LINAC are mounted around the ring and rotate around an axis passing through the isocenter. The gantry-based system can further include a C-arm gantry, in which the kV imaging source and the LINAC are mounted in a cantilevered manner and rotate around an axis passing through the isocenter. In another embodiment, the kV imaging source and the LINAC can be used in a robotic arm-based system that includes a robotic arm to which the kV imaging source and the LINAC are mounted.

[0036] As is apparent from the above description, unless otherwise specified, terms such as "processing", "computing", "generating", "comparing", "determining", "calculating", "performing", "identifying", etc. can be understood to refer to the operations and processes of a computer system or a similar electronic computer device that manipulates data represented as physical (e.g., electronic) quantities in the registers and memories of the computer system and converts it into other data similarly represented as physical quantities in the memory or registers of the computer system or other such information storage or display devices. Embodiments of the methods described herein can be implemented using computer software. When written in programming compliant with an authorization standard, the instruction sequences designed to execute this method can be compiled for execution on a variety of hardware platforms and interfaces to a variety of operating systems. Additionally, embodiments of the present disclosure are not described with reference to any particular programming language. It will be understood that embodiments of the present disclosure can be implemented using a variety of programming languages.

[0037] Note that the methods and apparatuses described herein are not limited solely to use in medical diagnostic imaging and treatment. In alternative embodiments, the methods and apparatuses herein can be used in applications other than the medical technology field, such as industrial imaging and non-destructive testing of materials. In such applications, for example, "treatment" can generally refer to the achievement of an operation controlled by a treatment planning system, such as the application of a beam (e.g., radiation, sound, etc.), and "target" can refer to a non-anatomical object or region.

[0038] The foregoing description of illustrative embodiments of the disclosure, including what is set forth in the Summary, is not intended to be exhaustive or to limit the disclosure to the forms disclosed. Specific embodiments and examples of the disclosure are described herein for illustrative purposes, and various equivalent modifications are possible within the scope of the disclosure as will be understood by those skilled in the art. The word "example" or "exemplary" is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs. On the contrary, the use of the word "example" or "exemplary" is intended to present concepts in a clear fashion. The term "or" as used in this application is not an exclusive "or" but rather an inclusive "or". That is, unless otherwise indicated or otherwise apparent from the context, "X includes A or B" is intended to mean any of the inclusive permutations necessarily. That is, "X includes A or B" is satisfied under any of the following instances: X includes A; X includes B; or X includes both A and B. Additionally, the articles "a" and "an" as used in this application and the appended claims should generally be construed to mean "one or more than one" unless otherwise indicated or otherwise apparent from the context as being indicated in the singular form. Further, the use throughout of the terms "an embodiment" or "one embodiment" or "an implementation" or "one implementation" is not intended to mean the same embodiment or implementation unless so described. The terms "first", "second", "third", "fourth", etc. as used herein mean labels for distinguishing different elements and do not necessarily have the meaning of ordinal numbers following their numerical representation.

[0039] In the foregoing specification, the disclosure has been described with reference to specific exemplary embodiments. However, it will be apparent that various modifications and changes can be made to the disclosure without departing from the broad spirit and scope of the disclosure as set forth in the appended claims. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a limiting sense.

Claims

1. Receiving identification information of an internal target region of a patient; In response to receiving the identification information, adjusting an aperture of a collimator of an X-ray imaging source of an X-ray imager to a first field of view (FOV) corresponding to the internal target region; Generating internal position data regarding the internal target region using the first FOV by the X-ray imager; Generating external position data regarding movement outside an external surface region of the patient using a motion detection device; Generating a correlation model between positions of the internal target region and the external surface region using the external position data and the internal position data; Predicting a predicted position of the internal target region at a subsequent time point based on the correlation model; Adjusting the aperture of the collimator of the X-ray imaging source to a second FOV corresponding to the predicted position of the internal target region; A method comprising the above.

2. Imaging a volume of interest (VOI) using the first field of view (FOV) from a first position having the X-ray imaging source, wherein the VOI includes a region of interest (ROI) of the patient, and further wherein the region of interest (ROI) includes the internal target region; Adjusting the aperture of the collimator of the X-ray imaging source to a second field of view (FOV) corresponding to the predicted position of the internal target region, the second field of view (FOV) being smaller than the first field of view (FOV); Imaging the region of interest (ROI) using the second field of view (FOV) from a second position having the X-ray imaging source; The method according to claim 1, further comprising the above.

3. The step of adjusting the aperture of the X-ray imaging source includes adjusting the size of the aperture to correspond to the size of the ROI, The method according to claim 2.

4. The step of adjusting the aperture of the X-ray imaging source includes adjusting the shape of the aperture to correspond to the shape of the RO I, The method according to claim 2.

5. The ROI in the VOI of the patient includes at least one fiducial marker positioned within the VOI, The method according to claim 2.

6. The ROI in the VOI of the patient includes anatomical features positioned within the VOI, The method according to claim 2.

7. The aperture of the X-ray imaging source is adjusted while the position having the X-ray imaging source moves from the first position to the second position. The method according to claim 2.

8. The X-ray imaging source includes a kilovoltage (kV) X-ray imaging source. The method according to claim 1.

9. The X-ray imaging source includes a megavoltage (MV) X-ray imaging source. The method according to claim 1.

10. The motion detection device includes one or more light-emitting diodes (LEDs) attached to the external surface area of the patient. The method according to claim 1.

11. The motion detection device includes an optical system that tracks the positions of one or more light-emitting diodes (LEDs). The method according to claim 10.

12. The identification information of the internal target area is based on a user selection of the internal target area. The method according to claim 1.

13. The identification information of the internal target area is based on automatic identification information of the internal target area. The method according to claim 1.

14. A therapeutic imaging system comprising a processing device operably coupled to an X-ray imager including an X-ray imaging source, wherein the processing device is configured to cause the therapeutic imaging system to perform the method according to any one of claims 1 to 13.

15. A non-transitory computer-readable storage medium having instructions, wherein the instructions, when executed by a processing device of a therapeutic imaging system, cause the therapeutic imaging system to perform the method according to any one of claims 1 to 13. A non-transitory computer-readable storage medium. ​

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