Imaging systems and methods

An image acquisition apparatus includes: a positioner controller communicatively coupled to a positioner, wherein the positioner controller is configured to generate a control signal to cause the positioner to rectilinearly translate a patient support relative to an imager, and/or to rectilinearly translate the imager relative to the patient support; an imaging controller configured to operate the imager to generate a first plurality of two-dimensional images for a patient while the patient is supported by the patient support, and while the positioner rectilinearly translates the patient support and/or the imager; and an image processing unit configured to obtain the first plurality of two-dimensional images and arrange the two-dimensional images relative to each other to obtain a first composite image.

FIELD

The field of the application relates to medical imaging, and more particularly, to systems and methods for imaging a patient before and/or during treatment.

BACKGROUND

Image guidance in radiation therapy is an essential tool to provide high quality treatments by aligning the patient's current anatomy with a planned configuration. The field of view of existing imaging modalities (e.g., 2D planar, CBCT imaging, etc.) may be restricted by the size of the image receptor to about 30 cm or less in length at isocenter level. To be able to treat longer patient volumes, image guidance needs to provide a longer field of view to provide sufficient confidence in the patient's alignment with respect to planned configuration. In some cases, the longitudinal field of view of CBCT may be extended by combining separate CBCT scan acquisitions from different couch positions. However, this approach may not be desirable because of its long acquisition time and because it results in high amount of non-treatment radiation dose being delivered to the patient.

SUMMARY

An image acquisition apparatus includes: a positioner controller communicatively coupled to a positioner, wherein the positioner controller is configured to generate a control signal to cause the positioner to rectilinearly translate a patient support relative to an imager, and/or to rectilinearly translate the imager relative to the patient support; an imaging controller configured to operate the imager to generate a first plurality of two-dimensional images for a patient while the patient is supported by the patient support, and while the positioner rectilinearly translates the patient support and/or the imager; and an image processing unit configured to obtain the first plurality of two-dimensional images and arrange the two-dimensional images relative to each other to obtain a first composite image.

An imaging method performed by an image acquisition apparatus, includes: generating a control signal by a positioner controller that is communicatively coupled to a positioner, wherein the control signal is generated to cause the positioner to rectilinearly translate a patient support relative to an imager, and/or to rectilinearly translate the imager relative to the patient support; operating the imager to generate a first plurality of two-dimensional images for a patient while the patient is supported by the patient support, and while the positioner rectilinearly translates the patient support and/or the imager; and arranging, by an image processing unit, the two-dimensional images relative to each other to obtain a first composite image.

Other and further aspects and features will be evident from reading the following detailed description.

DETAILED DESCRIPTION

FIG.1illustrates a treatment system10. The system10is a radiation treatment system that includes a gantry12, a patient support14for supporting a patient28, and a control system18for controlling an operation of the gantry12. The gantry12is in a form of an arm, but in other embodiments, the gantry12may have other forms (such as a ring form, etc.). The system10also includes a radiation source20that projects a beam26of radiation towards a patient28while the patient28is supported on support14, and a collimator system22for controlling a delivery of the radiation beam26. The collimator22may be configured to adjust a cross sectional shape of the beam26. The radiation source20can be configured to generate a cone beam, a fan beam, or other types of radiation beams in different embodiments.

As shown in the figure, the system10also includes an imager80, located at an operative position relative to the source20(e.g., under the support14). In the illustrated embodiments, the radiation source20is a treatment radiation source for providing treatment energy. In such cases, the treatment energy may be used by the imager80to obtain images. In order to obtain imaging using treatment energies, the imager80is configured to generate images in response to radiation having treatment energies (e.g., MV imager). In other embodiments, in addition to being a treatment radiation source, the radiation source20can also be a diagnostic radiation source for providing diagnostic (imaging) energy for imaging purpose. In further embodiments, the system10may include the radiation source20for providing treatment energy, and one or more other radiation sources for providing diagnostic energy. In some embodiments, the treatment energy is generally those energies of 160 kilo-electron-volts (keV) or greater, and more typically 1 mega-electron-volts (MeV) or greater, and diagnostic energy is generally those energies below the high energy range, and more typically below 160 keV. Also, in some embodiments, a treatment energy may be 6 MV or higher (e.g., 25 MV). In other embodiments, the treatment energy and the diagnostic energy can have other energy levels, and refer to energies that are used for treatment and diagnostic purposes, respectively. In some embodiments, the radiation source20is able to generate X-ray radiation at a plurality of photon energy levels within a range anywhere between approximately 10 keV and approximately 20 MeV. In other embodiments, the radiation source20may be configured to generate radiation at other energy ranges, such as a range that is below 160 keV, a range from 1 MeV to 12 MeV or less, etc.

In the illustrated embodiments, the control system18includes a processing unit54, such as a computer processor, coupled to a control40. The control system18may also include a monitor56for displaying data and an input device58, such as a keyboard or a mouse, for inputting data. The operation of the radiation source20and the gantry12are controlled by the control40, which provides power and timing signals to the radiation source20, and controls a rotational speed and position of the gantry12, based on signals received from the processing unit54. In some cases, the control40may also control the collimator system22and the position of the patient support14. In addition, in some embodiments, the control40may be configured to control an operation of the imager80. Although the control40is shown as a separate component from the gantry12and the processor54, in alternative embodiments, the control40can be a part of the gantry12or the processing unit54.

In some embodiments, the system10may be a treatment system configured to deliver a treatment radiation beam towards the patient28at different gantry angles. During a treatment procedure, the source20rotates around the patient28and delivers a treatment radiation beam from different gantry angles towards the patient28. While the source20is at different gantry angles, the collimator22is operated to change the shape of the beam to correspond with a shape of the target tissue structure. For example, the collimator22may be operated so that the shape of the beam is similar to a cross sectional shape of the target tissue structure. In another example, the collimator22may be operated so that different portions of the target tissue structure receive different amount of radiation (as in an IMRT procedure).

In the illustrated embodiments, the system10also includes an imaging device150having an imaging source152and an imager154. The imaging device150is configured to obtain one or more images of an internal part of the patient28. The image(s) obtained by the imaging device150may be used to setup the patient28, monitor a position of the patient28, track a target within the patient28, or any combination of the foregoing. In some cases, the imaging device150may be configured to obtain images of an internal fiducial90of the patient28. The internal fiducial90may be an internal structure inside the patient28. In some embodiments, the internal structure may move in correspondence (e.g., in sync) with a target of the patient28that is desired to be treated. In such cases, the internal structure may be used as a surrogate for determining a position and/or movement of the target during treatment of the patient28, and motion management based on the surrogate may be employed in some cases. Thus, the internal fiducial90may be imaged by the imaging device150(and/or by the radiation source20and imager80) that functions as a position monitoring system during a treatment of the patient28. By means of non-limiting examples, the internal fiducial90may be an anatomical surrogate, such as bony structure, a vessel, a natural calcification, or any other items in a body. As discussed, the imaging device150and/or the imager80may also be used for target tracking and/or patient positioning. In some embodiments, the control40may be configured to control an operation of the imaging device150and/or the patient support14. For example, the control40may provide one or more control signals to activate the imaging source152, and/or to operate a readout and control circuit in the imager154. The control40may also operate a positioner to move the patient support14and/or the imaging device150.

In some embodiments, the imaging device150may be a x-ray device. In such cases, the imaging source152comprises a radiation source (e.g, a kV source). In other embodiments, the imaging device150may have other configurations, and may be configured to generate images using other imaging techniques. For example, in other embodiments, the imaging device150may be an ultrasound imaging device, a MRI device, a tomosynthesis imaging device, or any of other types of imaging devices. Also, in the above embodiments, the imaging device150is illustrated as being integrated with the treatment machine. In other embodiments, the imaging device150may be a separate device that is separate from the treatment machine. In addition, in some embodiments, the imaging device150may be a room-based imaging system or a couch based imaging system. In either case, the imaging device150may provide any form of imaging, such as x-ray imaging, ultrasound imaging, MRI, etc. Furthermore, in other embodiments, the imaging device150may provide in-line imaging in the sense that it may be configured to acquire images along the same direction as the treatment beam. For example, a dual-energy source (integrating the treatment source20and the imaging source152) may be provided to provide imaging energy for generating an image, and to provide treatment energy to treat a patient along the same direction. In such cases, the imager154may replace the imager80, or may be integrated with the imager80to form a hybrid-imager, which is configured to provide kV and MV imaging. In still further embodiments, the imaging device150and/or the imaging device80may be configured to provide dual energy imaging and any form of energy-resolved imaging to increase contrast in x-ray images. For example, a first part of an image may be generated using a first energy, and a second part (e.g., a more relevant part that includes a target) of the same image may be generated using a second energy that is higher than the first energy. As a result, the second part of the image may have higher contrast compared to the first part. However, the overall dose involved in generating the whole image may be reduced compared to the situation in which the entire image is generated using the second energy.

FIG.2illustrates an example of an imager200. The imager200may implement as the imager154or the imager80ofFIG.1in some embodiments. The imager200is configured to receive imaging radiation from an imaging source (e.g., source152or20), and generates image signals in response to the imaging radiation. The imager200includes a layer202of scintillator (or scintillator layer202) configured to receive the imaging radiation, and to generate light in response to the imaging radiation. The scintillator layer202may be pixelated or non-pixelated. The imager200also includes an array204of imager elements206. Each imager element206is configured to generate image signal(s) in response to light received from the scintillator layer202. Scintillators for imagers are known in the art, and any of such scintillators may be used to implement the imager200.

In some embodiments, each imager element206may include one or more amorphous silicon (a:Si) detector. Also, in some embodiments, the imager element206may be implemented using a photodiode. In this specification, the term “photodiode” refers to one or more electrical circuit element(s) on a detector pixel that are associated with converting photon energy into electrical signals. This can include, but is not limited to, photodiode(s), switching transistor(s), amplification transistor(s), direct conversion element, indirect conversion elements, photon counting elements, or a combination thereof. In some embodiments, the electrical circuit element(s) of the imager element206is designed (e.g., being made from radiation resistant material, and/or having a configuration) to be radiation hard. The scintillator layer202is configured to receive radiation and generate photons in response to the radiation. The photodiode element of the imager element206is configured to generate electrical signals in response to the photons provided from the scintillator layer202. The electrical signals are then read out by readout and control circuit230, and are digitized to form an image. In the illustrated embodiments, the readout and control circuit230is designed (e.g., being made from radiation resistant material, and/or having a configuration) to be radiation hard. In some embodiments, the readout and control circuit230is communicatively connected to the control40, or another separate control, for controlling an operation of the readout and control circuit230.

In some embodiments, signal from each photodiode of each imager element206forms a pixel in an image. In other embodiments, a binning circuit is optionally provided to combine the signals from two or more photodiodes of two or more respective imager elements206to form each pixel in the image. For example, the binning circuit of the imager200may be configured to provide 2×2 binning, 3×3 binning, 4×4 binning, 1×2 binning, 1×4 binning or binning of other number of pixels. In some embodiments, the binning circuit may be designed (e.g., being made from radiation resistant material, and/or having a configuration) to be radiation hard. For example, the binning circuit may include circuit components configured to withstand radiation. The binning circuit may be implemented as a part of the access and control circuit230in some embodiments.

As shown inFIG.2, the imager200further includes a glass substrate220, wherein the array204of imager elements206is secured to the glass substrate220. In the illustrated embodiments, the glass substrate220has a first side222and an opposite second side224, wherein the first side222is closer to a radiation source than the second side224. In some embodiments, the array204of imager elements206is located closer to the first side222of the glass substrate220than the second side224. In other embodiments, the substrate220may be made from other materials that are different from glass. For example, in other embodiments, the substrate220may be made from plastic.

FIG.3depicts one exemplary configuration of electrical components for the imager200in accordance with some embodiments. The imager200includes a plurality of imager elements304(i.e.,304a-304d) having respective photodiodes306(i.e.,306a-306d). The photodiodes306form part of the imager element206ofFIG.2. Each of the photodiodes306is configured to generate an electrical signal in response to a light input. The photodiode306receives light input from the scintillator layer202that generates light in response to x-rays. The photodiodes306are connected to an array bias voltage322to supply a reverse bias voltage for the imager elements304. A transistor308(such as a thin-film N-type FET) functions as a switching element for each imager element304. When it is desired to capture image data from the imager elements304, control signals314are sent to a gate driver312to “select” the gate(s) of transistors308. The gate driver312is connected to a low gate voltage327and high gate voltage source that drives the gate control lines326a,326b. In particular, the gate driver312provides drive signals to the gate control lines326a,326b. In response to the drive signals, electrical signals from the photodiodes306are passed through lines316(i.e.,316a-316d) to corresponding charge amplifiers310a-310d, which are connected to a reference voltage via lines370a-370d, respectively. The output of the charge amplifiers310is sent via outputs320(e.g.,320a-320d) to a “sample and hold” stage for further image processing/display. In one embodiment, the gate driver312is a part of the readout and control circuit230ofFIG.2, which may be located along one or more side(s) of the imager200. The readout and control circuit230may include one or more of the components shown inFIG.3, such as the gate driver312, the charge amplifiers310, the outputs320, gate control lines326, lines316, lines370, reference voltage source and/or conductor of the reference voltage, array bias voltage and/or conductor of the array bias voltage, high and low gates voltage source and/or conductor of the high and low gates voltage, the digital control circuits, or any combination of the foregoing. In some embodiments, one or more (e.g., all) of the above components of the readout and control circuit230may be radiation hard. In addition, in some embodiments, the readout and control circuit230may be a part of an integrated circuit, wherein a part or an entirety of the integrated circuit may be radiation hard. Such circuit may include any of the components of the readout and control circuit230described above, including but not limited to gate driver312, charge amplifiers310, digital control circuits, etc.

WhileFIG.3only shows four imager elements304a-304d, those skilled in the art understand that the imager200may include many such imager elements304, depending upon the size and resolution of the imaging device. In addition, although only two gate control lines326aand326bfor accessing image signals from imager elements304are shown, the imager200may include more than two gate control lines326. In the illustrated embodiments, the gate driver312has multiple outputs362accessing respective gate control lines326, one line at a time. In other embodiments, the gate driver312may be configured to access multiple (e.g., two, four, six, etc.) gate control lines326simultaneously. For example, each output362of the gate driver312may connect to multiple gate control lines326for accessing the multiple gate control lines326simultaneously. Such configuration allows image signals to be collected from two or more lines of imager elements304simultaneously, thereby increasing the signal collection process. For a given configuration of the imager200, a signal readout time for each gate control line326of imager elements304depends on the time it takes to turn on a pixel and discharge a corresponding image signal. As such, by configuring the imager200to allow image signals from two or more lines of imager elements304to be read simultaneously or in parallel, the time it takes to readout image signals from all the lines of the imager200can be reduced. This in turn, improves the frame rate (i.e., number of image frames that can be generated by the imager200per second) of the imager200.

It should be noted that the electrical components and the electrical layout of the imager200should not be limited by the example shown inFIG.3, and that in other embodiments, the imager200may have electrical component(s) and/or electrical layout that is different from that shown inFIG.3.

It should be noted that the imager200described herein is not limited to withstand radiation resulted from treatment beam generated by electrons striking a target. In other embodiments, the imager200described herein may be for withstanding radiation resulted from other types of particle beams, such as proton beams. For example, the imager200described herein may be used with a proton treatment machine. In such cases, the features described herein may allow the imager200to withstand radiation resulted from the delivery of proton treatment beam.

Furthermore, the imager200is not limited to having the scintillator layer202. In other embodiments, the imager200may be other types of imager, such as those that may not require any scintillator layer. For example, as discussed, in other embodiments, the imager200may include a conversion layer that is configured to generate electron-hole pairs in response to radiation. In such cases, image signals are generated directly by the conversion layer, and the imager200may not include any scintillator layer. Also as similarly discussed, in further embodiments, the imager200may include photon counters configured to generate image(s) based on photon counting. Imagers with conversion layers and photon counters are known in the art, and any of such imagers may be used to implement the imager200. The imager200may be any other type of imager in other embodiments.

Imagers in radiation therapy systems and in diagnostic radiation system are well known in the art, and any of such imagers may be used to implement the imager200.

FIG.4illustrates an image acquisition apparatus400in accordance with some embodiments. The image acquisition apparatus400may be implemented in the treatment system10ofFIG.1. For example, the image acquisition apparatus400may be implemented as a part of the processing unit54, or as a separate component that is communicatively coupled to the processing unit54and/or the control40. The image acquisition apparatus400includes: a positioner controller402communicatively coupled to a positioner404, wherein the positioner controller402is configured to generate a control signal to cause the positioner404to rectilinearly translate the patient support14relative to the imager154and the imaging source152, and/or to rectilinearly translate the imager154and the imaging source152relative to the patient support14. The image acquisition apparatus400also includes an imaging controller410configured to operate the imager154to generate a first plurality of two-dimensional images420for a patient while the patient is supported by the patient support14. The image acquisition apparatus400further includes an image processing unit430configured to obtain the first plurality of two-dimensional images420and arrange the two-dimensional images420relative to each other to obtain a first composite image440.

In some embodiments, the positioner controller402is configured to operate the positioner404to rectilinearly translate the patient support14or the imaging device150in a direction that corresponds with (e.g., parallel to) a longitudinal axis of the patient28. In one implementation, as the patient support14is being rectilinearly translated, the imaging device150remains stationary (e.g., the imaging source152and the imager154does not rotate nor translate). In another implementation, as the imaging device150is being rectilinearly translated, the patient support14remains stationary. In a further implementation, the patient support14and the imaging device150may be rectilinearly translated in opposite directions. In some cases, the positioner controller402is configured to generate the control signal to cause the positioner404to translate the patient support14at a rate that is at least 80% of the maximum speed of the patient support14, and/or the imaging device150at a rate that is at least 80% of the maximum speed of the imaging device150. This allows different parts of the patient supported by the patient support14to be imaged by the imaging device150quickly. In other embodiments, the positioner404may translate the patient support14at other speeds, which may be below 80% of the maximum speed of the patient support14. Also, in other embodiments, the positioner404may translate the imaging device150at other speeds, which may be below 80% of the maximum speed of the imaging device150.

The positioner controller402may also operate the positioner404to rotate the imaging device150(the imaging source152and the imager154) around the patient so that the imaging device150can image the patient from a different angle. As used in this specification, the term “positioner” may refer to one or more mechanical movers. For example, the positioner404may be a first mechanical component attached to the patient support14for moving the patient support, may be a second mechanical component attached to the imaging device150for moving the imaging device150or part(s) thereof, or may be both the first and second mechanical components.

The imaging controller410is configured to operate the imaging source152and/or the imager154to generate two-dimensional images420for a patient while the patient is supported by the patient support14. The imaging controller410may communicatively couple to readout and control circuit (e.g., readout and control circuit230) of the imager154. The imaging controller410may also communicatively couple to the imaging source152. In some embodiments, as the positioner404rectilinearly translates the patient support14relative to the imaging source152and the imager154, the imaging controller410generates signals to operate the imaging source152and the imager154to image different parts of the patient along a longitudinal axis of the patient. In other embodiments, as the positioner404rectilinearly translates the imaging source152and the imager154relative to the patient support14, the imaging controller410generates signals to operate the imaging source152and the imager154to image different parts of the patient along a longitudinal axis of the patient. In either case, the imaging of the patient results in multiple two-dimensional images of different parts of the patient that are along a longitudinal axis of the patient. The imaging planes of the respective two-dimensional images are parallel with respect to each other and all lie within the same plane. This allows the image processing unit430to stitch the two-dimensional images together in some embodiments to form the composite image440.

In some embodiments, the imaging controller410is configured to operate the imager154to generate the plurality of two-dimensional images420within 20 seconds or less. Accordingly, the patient only needs to be imaged for 20 seconds or less, and the image acquisition apparatus400will have sufficient image data to create the composite image440for the patient. Due to the advantage of such short imaging time, the patient may be instructed to perform breath hold while the imager154generates the two-dimensional images420. Also, in some embodiments, the two-dimensional images420that are generated within 20 seconds or less (e.g., within 15 seconds, within 12 seconds, within 10 seconds, etc.) collectively cover a length of the patient that is at least 50 cm or more, 60 cm or more, 70 cm or more, 80 cm or more, 90 cm or more, or 100 cm or more. In some embodiments, the first plurality of two-dimensional images420comprises at least 50 images, at least 60 images, at least 70 images, at least 80 images, at least 90 images, at least 100 images, or more. Furthermore, in some embodiments, the imaging controller410is configured to operate the imager154to generate the first plurality of two-dimensional images420at 10 frames per second or higher, 20 frames/sec or higher, 30 frames/sec or higher, or 40 frames/sec or higher.

In some embodiments, the image acquisition apparatus400may be configured to operate the imager154in a full resolution imaging mode (i.e., no binning of image data). In such cases, the imager154is operated at a first frame rate (e.g., 10 frames/second) that is less than a maximum frame rate. In such example, the patient travel distance per frame may be 1 cm/frame for example. In other embodiments, the image acquisition apparatus400may be configured to operate the imager154in reduced longitudinal resolution (e.g., 1×4 binning). This may allow higher readout mode to be implemented. In some cases, a shorter travel distance of 0.33 cm/frame can be achieved with a higher frame rate (e.g., 30 frames/second). In further embodiments, the imaging acquisition apparatus400may operate the imager154in full resolution imaging mode for this higher frame rate.

Also, in the illustrated embodiments, the imaging controller410is configured to control the imaging source152to deliver imaging energy (e.g., radiation) in pulses. In some cases, the imaging source152may deliver imaging energy in pulses that are synchronized to the imager's154frame rate. In other embodiments, the imaging controller410is also configured to control the imaging source152to deliver imaging energy (e.g., radiation) continuously—e.g., for at least 2 seconds, at least 4 seconds, at least 5 seconds, or at least 6 seconds. While the imaging source152is “on” continuously, the patient support14is translated relative to the imaging source152and the imager154to allow the imager154to image different parts of the patient. Alternatively, while the imaging source152is “on” continuously, the imaging source152and the imager154are translated relative to the patient support14to allow the imager154to image different parts of the patient. In further embodiments, the imaging source152may be selectively operated in a pulse mode (in which imaging energy is delivered in pulses) or a continuous mode (in which imaging energy is delivered continuously).

The image processing unit430is configured to obtain the plurality of two-dimensional images420and arrange the two-dimensional images420relative to each other to obtain a first composite image440. In some embodiments, the image processing unit430is configured to obtain the composite image440by performing image stitching using the two-dimensional images420. In one implementation, the image processing unit430is configured to identify overlapping regions of at least two adjacent two-dimensional images420. In such cases, the stitching of the two adjacent two-dimensional images420may be performed based on the identified overlapping regions. Also in some embodiments, the image processing unit430is configured to obtain couch positions for the patient support14or imager positions for the imager154, and utilize the couch positions and/or the imager positions to arrange the two-dimensional images420with respect to a reference coordinate for the composite image440to be formed. As used in this specification, the term “couch position” refers to a position of a patient support (e.g., bed) that is for supporting a patient, wherein the position may be a location and/or an orientation of the patient support. The image processing unit430may also be configured to obtain meta data for the respective two-dimensional images420, and utilize the meta data to map the two-dimensional images420to the reference coordinate for the composite image440to be formed. By means of non-limiting examples, the meta data may be positions of the imager154that correspond with the respective two-dimensional images420, positions of the patient support14that correspond with the respective two-dimensional images420, relative positions between the patient support14and the imager154that correspond with the respective two-dimensional images420, time stamps of the respective two-dimensional images420indicating when they are generated, or any combination of the foregoing. In some embodiments, the composite image440created from the two-dimensional images420may cover (span) at least a portion of the patient that is at least 50 cm or more, 60 cm or more, 70 cm or more, 80 cm or more, 90 cm or more, or 100 cm or more, in length.

In some embodiments, an arbitrary reference couch position may be specified. In such cases, all metadata of the acquired two-dimensional images420may be set with respect to the specified reference couch position. For example, for each acquired two-dimensional image420, the imager position of the imager154relative to the reference couch position at the time of acquisition may be used to determine the relative position of the two-dimensional image420with respect to the reference couch position. In other embodiments, instead of a reference couch position, any arbitrary reference position or reference coordinate frame may be set. In such cases, the positions of the two-dimensional images420may be determined with respect to such arbitrary reference position or reference coordinate frame. In some embodiments, the positions of the two-dimensional images420may be used to stitch the two-dimensional images420to create the composite image440. In other embodiments, the determining of the positions of the two-dimensional images420itself may be considered a stitching of the two-dimensional images420. In some embodiments, the reference coordinate frame may have a width and height defined for the composite image440to be formed, wherein such width and height are selected to span the maximum extent of all acquired two-dimensional images420. Image information for each two-dimensional image420is copied or placed into the reference coordinate frame at its corresponding relative position within the reference coordinate frame. Redundant image information in the overlap areas between adjacent images420may be combined to produce a continuous image.

In some embodiments, the composite image440may comprise a left or right side view of the patient. In other embodiments, the composite image440may comprise a top or bottom view of the patient. In further embodiments, the image acquisition apparatus400may be configured to create two or more composite images440. For example, the image acquisition apparatus400may operate the positioner404to place the imaging device150at a first orientation with respect to the patient to image from a left or right side of the patient. The image acquisition apparatus400may then operate the imaging device150to create a first plurality of two-dimensional images having side views of the patient. The image processing unit430then creates a first composite image440based on the first plurality of two-dimensional images. For example, the image processing unit430may arrange the two-dimensional images420in the first plurality of two-dimensional images420relative to each other to obtain the first composite image440. The image acquisition apparatus400may then operate the positioner404to place the imaging device150at a second orientation with respect to the patient to image from a top or bottom side of the patient. The image acquisition apparatus400may then operate the imaging device150to create a second plurality of two-dimensional images having top or bottom views of the patient. The image processing unit430then creates a second composite image440based on the second plurality of two-dimensional images. For example, the image processing unit430may arrange the two-dimensional images420in the second plurality of two-dimensional images420relative to each other to obtain the second composite image440.

In some cases, the plurality of two-dimensional images420is obtained at a same isocenter position associated with a treatment machine, such as that shown inFIG.1. This is advantageous in that bending of the patient support due to weight of the patient may not need to be accounted for.

Also, in some embodiments, the image acquisition apparatus400may implement an imager readout mode that allows readout of regions-of-interest (ROIs) with reduced height to achieve a higher frame rate (e.g., 30 fps) at native pixel size resolution. This technique may reduce or eliminate merge artifacts. In one implementation, the imaging source152may be vertically collimated to provide only a strip of imaging radiation with reduced height that corresponds with a desired height of a region-of-interest (ROI). This has the benefit of reducing dose delivered to the patient. Also, in some embodiments, information from overlapping scans may be utilized to reduce noise and/or to increase spatial resolution, in order to improve image quality. In further embodiments, auto-exposure mechanism may be employed to improve or optimize image contrast and/or to reduce excessive dose.

As shown inFIG.4, the image acquisition apparatus400includes a non-transitory medium450for storing the composite image(s)440. The non-transitory medium450may also store different sets of the two-dimensional images420that correspond with the respective composite images440. In some embodiments, the two-dimensional images420may be stored in the non-transitory medium450in association with their respective meta data, such as time stamps indicating when the images420were created, positions of the imager154and/or the patient support14when the respective images420were created, etc. The non-transitory medium450may include one or more storage device(s), and is not limited to a single storage device. In some embodiments, the two-dimensional images420and/or the composite image(s)440may also be outputted by the image acquisition apparatus400for display and presentation to a user.

After the composite image(s)440have been generated by the image processing unit430, the composite image(s)440may be utilized for various purposes. In some embodiments, the composite image(s)440may be used to align the patient with respect to the treatment system10. In one implementation, the alignment of the patient with respect to the treatment system10may be performed based on a comparison of at least a part of the composite image440with at least a part of a reference image. As used in this specification, the term “reference image” refers to any image that is generated ahead of time for use as a reference (e.g., for comparison with another later generated image, for processing with a later generated image, etc.). The reference image may be a CT image, a section of a CT image, an x-ray image, or any other types of image that was generated during treatment planning. The reference image is registered with the treatment plan and it indicates a desired positioning of the patient with respect to a treatment scheme. As shown inFIG.4, the image acquisition apparatus400also includes an image comparator460configured to compare at least a part of the composite image440with at least a part of a reference image to align the at least a part of the composite image440with the at least a part of the reference image. In some embodiments, the positioner controller402is configured to move the patient support14to place the patient at a desired position with respect to the treatment system10based on an alignment between at least a part of the composite image440and the at least a part of the reference image.

The composite image(s)440may also be used to form volumetric image(s) in some embodiments. As shown inFIG.4, the image acquisition apparatus400further includes a volumetric image processor470configured to construct a volumetric image based on the composite image440. For example, in some embodiments, the composite image440may contain information (e.g., geometry of anatomy, including sizes and shapes of various anatomical structures in the patient, etc.) that is useful in the generation of the volumetric image. In such cases, the volumetric image processor470will obtain the composite image440(either from the image processing unit430or from the medium450), and consider the information in the composite image440in the construction of the volumetric image. The volumetric image generated by the volumetric image processor470based on the plurality of two-dimensional images420may be a CT image or a tomosynthesis image.

Also, in some embodiments, the composite image(s)440may be used as prior information for generation of a stitched cone beam computed tomography (CBCT) image. For example, the volumetric image processor470may be configured to use the composite image440as a map for stitching different CBCT images together to form a composite CBCT image (e.g., super-CBCT image). Techniques for stitching CBCT images are known in the art, and therefore will not be described in further detail herein.

FIG.5illustrates an imaging scheme. The imaging scheme may be implemented using the image acquisition apparatus400. As shown in the figure, in one implementation, the patient support14is rectilinearly translated while the patient is being supported thereon. The movement of the patient support14may be achieved by a positioner that mechanically couples to the patient support14. The patient support14is translated in a direction so that different parts of the patient can be imaged by the imaging device150(comprising the imaging source152and the imager154). In the illustrated example, the direction of translation corresponds (e.g., is parallel, or form an angle that is less than 10° with respect) to a longitudinal axis500of the patient/the patient support14. In other examples, the direction of translation may be perpendicular to the longitudinal axis500, or form other angles (that are different from 0°, 90°, and 180°) with respect to the longitudinal axis500. Also, in the illustrated example, the imager154is at the right side of the patient, which allows the imager154to image the patient from the right side. Alternatively, the imager154may be placed at the left side of the patient to image the patient from the left side. In addition, in some embodiments, the imager154may be placed above the patient to image the patient from the front of the patient. Alternatively, the imager154may be placed under the patient to image the patient from the back of the patient. In other embodiments, instead of translating the patient support14, the imaging device150may be rectilinearly translated relative to the patient to image different parts of the patient. In such cases, the movement of the imaging device150may be achieved by a positioner that mechanically couples to the imaging device150. In further embodiments, both the patient support14and the imaging device150may be moved relative to each other to image different parts of the patient.

In the illustrated example shown inFIG.5, while the imaging device150is at different imaging positions with respect to the patient, the image acquisition apparatus400generates control signals to operate the imaging source152and the imager154to image different parts of the patient14along the axis500to create a plurality of two-dimensional images. The image acquisition apparatus400may then create a composite image based on the two-dimensional images. In one implementation, the two-dimensional images are stitched together to form the composite image.

In some embodiments, the image acquisition apparatus400may be configured to operate the imaging device150so that it creates two composite images of the patient. For example, the image acquisition apparatus400may create a first composite image based on the imaging scheme shown inFIG.5. The image acquisition apparatus400may also operate a positioner to rotate the imaging device150to place the imager154and the imaging source152at another position with respect to the patient. For example, the imager154and the imaging source152may be rotated about the axis500by 90°, so that the imager154can image the patient from the front or back of the patient. After the imaging device150has been moved, the image acquisition apparatus400can then rectilinearly translate the imaging device150(imaging source152and the detector154), rectilinearly translate the patient support14, or both the imaging device150and the patient support14, to generate a second plurality of two-dimensional images. The image acquisition apparatus can then generate the second composite image based on the second plurality of two-dimensional images.

The imaging scheme described herein results in a sequence of overlapping images.FIG.6illustrates a sequence600of overlapping two-dimensional images602. The two-dimensional images602collectively form a composite image610. The two-dimensional images602may be examples of the images420discussed with reference toFIG.4, and the composite image610may be an example of the composite image discussed with reference toFIG.4. As shown inFIG.6, each of the images602has one or more overlapping regions620with adjacent image(s). In some embodiments, the image processing unit430of the image acquisition apparatus400is configured to identify the overlapping region620between each adjacent pair of images602, and align the adjacent pair of images602with respect to each other based on the identified overlapping region620. The aligning of the adjacent images602may be accomplished by moving an image602in one or more directions within a plane of the image602(e.g., along an x-axis and/or along an y-axis). Also, in some embodiments, the image processing unit430is configured to stitch adjacent images602so that they collectively form the composite image610. The stitching of the images602may involve removing a portion of an image602that overlaps with an adjacent image602. In some cases, the stitching of the images602may include blending two overlapping portions of adjacent images602. Also, in some embodiments, the stitching of the images602may be accomplished by arranging (e.g., placing) each image602in a coordinate system630of the composite image to be formed. The arranging of the image602in the coordinate system630may be accomplished graphically. Alternatively, or additionally, the arranging of the image602in the coordinate system630may be accomplished by assigning a position (e.g., X, Y coordinates) for the image602with respect to the coordinate system630. In one implementation, the assigning of the position for the image602may be based on an overlapping of the image602with adjacent image602. For example, if a first image602is assigned (X1, Y1) in the coordinate system630for the composite image620to be formed, an adjacent image (e.g., a second image602) may be assigned coordinate (X2, Y2) in the coordinate system630, wherein the coordinate (X2, Y2) may be determined based on a region in the second image602that overlaps a region in the first image602. This is performed for each of the images602until all of the images602is placed in the coordinate system630of the composite image610.

FIG.7illustrates an imaging method700. The imaging method700may be performed by the image acquisition apparatus400in some embodiments. The imaging method700includes: generating a control signal by a positioner controller that is communicatively coupled to a positioner, wherein the control signal is generated to cause the positioner to rectilinearly translate a patient support relative to an imager, and/or to rectilinearly translate the imager relative to the patient support (item702). The imaging method700also includes operating the imager to generate a first plurality of two-dimensional images for a patient while the patient is supported by the patient support (item704). The imaging method700further includes arranging, by an image processing unit, the two-dimensional images relative to each other to obtain a first composite image (item706).

Optionally, in the method700, the first composite image is obtained by performing image stitching using the two-dimensional images.

Optionally, the method700also includes identifying an overlapping region of at least two of the two-dimensional images.

Optionally, in the method700, the first composite image covers at least a portion of the patient that is 50 cm or more, 60 cm or more, 70 cm or more, 80 cm or more, 90 cm or more, or 100 cm or more, in length.

Optionally, in the method700, the imager is operated by an imaging controller to generate a second plurality of two-dimensional images for the patient; and wherein the image processing unit is configured to obtain the second plurality of two-dimensional images and arrange the two-dimensional images in the second plurality of two-dimensional images relative to each other to obtain a second composite image.

Optionally, in the method700, the first composite image comprises a left or right side view of the patient, and wherein the second composite image comprises a top or bottom view of the patient.

Optionally, the method700further includes comparing, by an image comparator, at least a part of the first composite image with at least a part of a reference image to align the at least a part of the first composite image with the at least a part of the reference image. The image comparator may be a part of the image processing unit430, or alternatively, may be a separate unit from the image processing unit430.

Optionally, in the method700, the patient support is moved by the positioner controller based on an alignment between the at least a part of the first composite image and the at least a part of the reference image.

Optionally, in the method700, the imager is operated by an imaging controller to generate the first plurality of two-dimensional images within 20 seconds or less.

Optionally, in the method700, the two-dimensional images that are generated within 20 seconds or less collectively cover a length of the patient that is at least 50 cm or more, 60 cm or more, 70 cm or more, 80 cm or more, 90 cm or more, or 100 cm or more.

Optionally, in the method700, the first plurality of two-dimensional images comprises at least 50 images, at least 60 images, at least 70 images, at least 80 images, at least 90 images, at least 100 images, or more.

Optionally, in the method700, the imager is operated by an imaging controller to generate the first plurality of two-dimensional images at 10 frames per second or higher, 20 frames/sec or higher, 30 frames/sec or higher, or 40 frames/sec or higher.

Optionally, in the method700, the image acquisition apparatus is communicatively coupled to an image energy source, wherein the image energy source is coupled to a treatment machine in a half-fan configuration, and wherein the patient support is located off-isocenter with respect to the treatment machine.

Optionally, in the method700, the first plurality of two-dimensional images is obtained at a same isocenter position associated with a treatment machine.

Optionally, in the method700, the control signal is generated by the positioner controller to cause the positioner to translate the patient support at a rate that is at least 80% of its maximum speed.

Optionally, in the method700, the image acquisition apparatus includes a CT image processor, and the method700further includes constructing a volumetric image by the CT image processor based on the first composite image.

Optionally, the method700further includes generating a volumetric image (e.g., tomosynthesis image/CT image) by the image processing unit based on the first plurality of two-dimensional images.

Optionally, the method700further includes controlling a radiation source by an imaging controller to deliver radiation continuously for at least 2 seconds, at least 4 seconds, at least 5 seconds, or at least 6 seconds.

Optionally, the method700further includes controlling a radiation source to deliver radiation in pulses.

Optionally, in the method700, the arranging of the two-dimensional images comprises obtaining couch positions for the patient support or imager positions for the imager, and utilizing the couch positions and/or the imager positions to arrange the two-dimensional images with respect to a reference coordinate for the composite image.

Optionally, in the method700, the arranging of the two-dimensional images comprises obtaining meta data for the respective two-dimensional images, and utilizing the meta data to map the two-dimensional images to a reference coordinate for the composite image.

In some embodiments, the patient support14may be positioned to align the patient with the isocenter of the treatment system10while the image acquisition apparatus400operates the imaging device150to image the patient. For example, the patient may be laterally aligned with respect to the isocenter axis, such that a center or a reference location of the patient is laterally centered with respect to the isocenter axis (while the patient may be translated along the isocenter axis). In other embodiments, the patient support may be positioned to align the patient off-isocenter with respect to the treatment system10. This configuration may be desirable when the imaging device150is not vertically aligned (e.g., is in a half-fan configuration) with the isocenter of the treatment system10.FIG.8illustrates the imaging source152of the imaging device150in a half-fan configuration. When in the half-fan configuration, the imaging source152is configured to provide a beam with a fan angle that is approximately half (e.g., 0.5±0.1) of the full-fan angle. Imaging devices in half-fan configuration and imaging techniques using half-fan geometry are well known in the art, and therefore will not be described in further detail. As shown in the figure, the patient support14is located off-isocenter with respect to the treatment system10. In such cases, different patient support positions may be used when acquiring top/bottom and side composite images440of the patient. For example, the patient support14, the imaging source152, and the imager154may be positioned as that shown in the figure when the imager154images the patient from underneath the patient support14. The imaging source152and the imager154may then be rotated about 90° (e.g., 90° plus or minus 15°) to image the patient from a side of the patient. The patient support14may then be moved to a different position to allow the imager154to image the patient from the side of the patient. Moving the patient support14to different positions for acquiring top/bottom and side scans is advantageous because it allows optimization of field of view of each projection (e.g., by moving the patient support14as close as possible towards the imager154for a larger field of view). In other embodiments, the top/bottom and side scans may be performed with the same lateral and vertical positions for the patient support14. This has the advantage of reducing or minimizing total image acquisition time and movement of the patient support14. In addition, in some embodiments, to improve patient positioning and to have a central position of the top/bottom and side images represent a vertical and horizontal projection of the patient center (as in AP and LAT views of CT scout scans), the gantry angle may be offset to compensate for the imager's154lateral offset in the half-fan configuration.

In some embodiments, the gantry angle may be selected such that the total viewing angle (defined to be Alpha1+Alpha2=AlphaTinFIG.8) is evenly distributed to both sides of vertical. In the example of the geometry shown in the figure, the positioning parameters may be based on the following relationships:
Alpha2+Beta=Alpha1−Beta  (Eq. 1)
Thus, Beta=(Alpha1−Alpha2)/2  (Eq. 2)
AlphaT=Arctan((D/2+d)/SID)+Arctan((D/2−d)/SID)  (Eq. 3)
D=SAD*sin(Beta)  (Eq. 4)
As an example, for imager with D=430 mm, d=175 mm, and SID=154 mm, then AlphaTmay be calculated as 15.7° based on Eq. 3. Also, Beta may be determined as 6.36°, and Delta is calculated as 11.08 cm based on Eq. 4. This Delta represents the amount of lateral offset to “move” the isocenter to place it below the imaging source152. In some embodiments, the isocenter “shift” direction may be based on the below scheme:

In some embodiments, the two-dimensional images420and the composite image400created using the technique described herein has different projection properties. For example, in a lateral direction, the image may correspond to a point projection, and in a longitudinal direction, the image may correspond to a parallel projection.FIG.9illustrates different types of projection geometries. In some embodiments, if the image has different projection features, processing of the image (e.g., that is involved in 2D/3D matching algorithm, digitally reconstructed radiograph (DRR), etc.) may be implemented in a way that considers such different features.

The image acquisition apparatus400and the image acquisition scheme disclosed herein are advantageous because they enable full-body treatment to be performed by the treatment system10. In some cases, using the technique described herein, two full-length two-dimensional scans may be acquired in the time of a single CBCT, and the required dose for the two two-dimensional scans (for creating the corresponding two composite images) is comparable to the dose required for a regular planar kV image.

The image acquisition scheme described herein is also advantageous over a technique in which targeted treatment area in the patient is split into different treatment plans, which would require image-guided alignment to be performed for each plan. For example, using the “plan-splitting” technique, as much as five separate plans (or more) would have to be created and administered in order to cover a full length of a patient. Such workflow is laborious in planning and execution. In some cases, multiple cone beam computed tomography (CBCT) volumes may be stitched to cover a longer range. However, each volumetric image requires generation of many projection images that result in significant dose delivered to the patient. Also, the generation of projection images for each CBCT image may take a long time (e.g., more than 20 seconds to cover 20 cm in length of the patient). So for 100 cm in length, the image acquisition time can be more than 100 seconds in order for the combined volumetric images to cover the desired length of the patient. Embodiments of the image acquisition technique described herein significantly reduce the image acquisition time, and the amount of imaging dose delivered to patient. For example, in some embodiments, the image acquisition technique described herein may allow imaging of a length of a patient that is more than 100 cm to be completed in less than 12 seconds.

Although the image acquisition apparatus400and the imaging acquisition scheme have been described with reference to the treatment system10, in other embodiments, the image acquisition apparatus400and the imaging acquisition scheme may be implemented in other types of treatment system, such as proton treatment system, ultrasound treatment system, etc.

Also, in further embodiments, the image acquisition apparatus400and the image acquisition scheme described herein may be implemented in an imaging system (instead of a treatment system). The imaging system may be a CT system, a tomosynthesis system, a radiograph system, an x-ray system, a diagnostic system, a simulator, etc. The image acquisition apparatus400may enhance a functionality of such imaging system by operating different components (e.g., imaging source, imager, etc.) of the imaging system to acquire multiple two-dimensional images in accordance with the imaging acquisition scheme described herein. The two-dimensional images may then be stitched to form a composite two-dimensional image (super-2D image) that functions as a scout image, a scanogram, a topogram, etc.

It should be noted that the image acquisition apparatus400may not include all of the components402,410,430,450,460,470in other embodiments. For example, in other embodiments, the image acquisition apparatus400may not include the image comparator460and/or the volumetric image processor470. Also, in other embodiments, the non-transitory medium450may not be a part of the image acquisition apparatus400. In such cases, the image acquisition apparatus400may be communicatively coupled to the non-transitory medium450, and may be configured to output information (e.g., two-dimensional images420, composite image(s)440, meta data of the images, etc.) for storage at the non-transitory medium450and/or for presentation to a user via a display. Furthermore, in some embodiments, two or more of the components402,410,430,450,460,470of the image acquisition apparatus400may be combined. For example, in some embodiments, the positioner controller402and/or the imaging controller410may be combined into a same module. The image acquisition apparatus400(or one or more components therein) may be implemented using hardware, software, or a combination of both.

Specialized Processing System

FIG.10is a block diagram illustrating an embodiment of a specialized processing system1600that can be used to implement various features described herein. For example, in some embodiments, the processing system1600may be used to implement the image acquisition apparatus400, or one or more of its components. Also, in some embodiments, the processing system1600may be used to implement the processing unit54ofFIG.1. The processing system1600may also be used to implement a control that controls an operation of the imager200, and/or a control that controls an operation of the treatment machine.

Processing system1600includes a bus1602or other communication mechanism for communicating information, and a processor1604coupled with the bus1602for processing information. The processor system1600also includes a main memory1606, such as a random access memory (RAM) or other dynamic storage device, coupled to the bus1602for storing information and instructions to be executed by the processor1604. The main memory1606also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by the processor1604. The processor system1600further includes a read only memory (ROM)1608or other static storage device coupled to the bus1602for storing static information and instructions for the processor1604. A data storage device1610, such as a magnetic disk, solid state disk, or optical disk, is provided and coupled to the bus1602for storing information and instructions.

The processor system1600may be coupled via the bus1602to a display167, such as a flat screen monitor, for displaying information to a user. An input device1614, including alphanumeric and other keys, is coupled to the bus1602for communicating information and command selections to processor1604. Another type of user input device is cursor control1616, such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to processor1604and for controlling cursor movement on display167. This input device typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y), that allows the device to specify positions in a plane.

In some embodiments, the processor system1600can be used to perform various functions described herein. According to some embodiments, such use is provided by processor system1600in response to processor1604executing one or more sequences of one or more instructions contained in the main memory1606. Those skilled in the art will know how to prepare such instructions based on the functions and methods described herein. Such instructions may be read into the main memory1606from another processor-readable medium, such as storage device1610. Execution of the sequences of instructions contained in the main memory1606causes the processor1604to perform the process steps described herein. One or more processors in a multi-processing arrangement may also be employed to execute the sequences of instructions contained in the main memory1606. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to implement the various embodiments described herein. Thus, embodiments are not limited to any specific combination of hardware circuitry and software.

The term “processor-readable medium” as used herein refers to any medium that participates in providing instructions to the processor1604for execution. Such a medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical, solid state or magnetic disks, such as the storage device1610. A non-volatile medium may be considered an example of non-transitory medium. Volatile media includes dynamic memory, such as the main memory1606. A volatile medium may be considered an example of non-transitory medium. Transmission media includes coaxial cables, copper wire and fiber optics, including the wires that comprise the bus1602. Transmission media can also take the form of acoustic or light waves, such as those generated during radio wave and infrared data communications.

Common forms of processor-readable media include, for example, a flexible disk, hard disk, magnetic tape, or any other magnetic medium, a CD-ROM, any other optical medium, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, solid state disks any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a processor can read.

Various forms of processor-readable media may be involved in carrying one or more sequences of one or more instructions to the processor1604for execution. For example, the instructions may initially be carried on a magnetic disk or solid state disk of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a network, such as the Internet. The processing system1600can receive the data on a network line. The bus1602carries the data to the main memory1606, from which the processor1604retrieves and executes the instructions. The instructions received by the main memory1606may optionally be stored on the storage device1610either before or after execution by the processor1604.

The processing system1600also includes a communication interface1618coupled to the bus1602. The communication interface1618provides a two-way data communication coupling to a network link1620that is connected to a local network1622. For example, the communication interface1618may be a local area network (LAN) card to provide a data communication connection to a compatible LAN. Wireless links may also be implemented. In any such implementation, the communication interface1618sends and receives electrical, electromagnetic or optical signals that carry data streams representing various types of information.

The network link1620typically provides data communication through one or more networks to other devices. For example, the network link1620may provide a connection through local network1622to a host computer1624or to equipment1626such as a radiation beam source and/or an imaging device or a switch operatively coupled to a radiation beam source and/or an imaging device. The data streams transported over the network link1620can comprise electrical, electromagnetic or optical signals. The signals through the various networks and the signals on the network link1620and through the communication interface1618, which carry data to and from the processing system1600, are exemplary forms of carrier waves transporting the information. The processing system1600can send messages and receive data, including program code, through the network(s), the network link1620, and the communication interface1618.

As used in this specification, terms such as “first”, “second”, etc., are used to identify different items, and do not necessarily refer to the order of items. For example, “first composite image” and “second composite image” refer to two different composite images (not that the “first composite image” is first in order, etc.).

Also, as used in this specification, the term “image” may refer to a displayed image and/or to an image that is in electronic form that is not displayed. Similarly, action(s) performed on such image, such as stitching, arranging, moving, etc., may be carried out graphically and/or electronically. For example, a stitching of two images may be performed and/or accomplished by assigning two respective positions for the two images in a coordinate system (wherein when the two images are placed at the two assigned positions, the two images will be combined so that their overlapping regions are aligned).

Exemplary imaging acquisition apparatuses and methods are set out in the following items:

An image acquisition apparatus includes: a positioner controller communicatively coupled to a positioner, wherein the positioner controller is configured to generate a control signal to cause the positioner to rectilinearly translate a patient support relative to an imager, and/or to rectilinearly translate the imager relative to the patient support; an imaging controller configured to operate the imager to generate a first plurality of two-dimensional images for a patient while the patient is supported by the patient support, and while the positioner rectilinearly translates the patient support and/or the imager; and an image processing unit configured to obtain the first plurality of two-dimensional images and arrange the two-dimensional images relative to each other to obtain a first composite image.

Optionally, the image processing unit is configured to obtain the first composite image by performing image stitching using the two-dimensional images.

Optionally, the image processing unit is configured to identify an overlapping region of at least two of the two-dimensional images.

Optionally, the first composite image covers at least a portion of the patient that is at least 100 cm in length.

Optionally, the imaging controller is also configured to operate the imager to generate a second plurality of two-dimensional images for the patient; and wherein the image processing unit is configured to obtain the second plurality of two-dimensional images and arrange the two-dimensional images in the second plurality of two-dimensional images relative to each other to obtain a second composite image.

Optionally, the first composite image comprises a left or right side view of the patient, and wherein the second composite image comprises a top or bottom view of the patient.

Optionally, wherein the image acquisition apparatus further includes an image comparator configured to compare at least a part of the first composite image with at least a part of a reference image to align the at least a part of the first composite image with the at least a part of the reference image.

Optionally, the positioner controller is configured to move the patient support based on an alignment between the at least a part of the first composite image and the at least a part of the reference image.

Optionally, the imaging controller is configured to operate the imager to generate the first plurality of two-dimensional images within 20 seconds or less.

Optionally, the two-dimensional images that are generated within 20 seconds or less collectively cover a length of the patient that is at least 100 cm.

Optionally, the first plurality of two-dimensional images comprises at least 50 images.

Optionally, the imaging controller is configured to operate the imager to generate the first plurality of two-dimensional images at 10 frames per second or higher.

Optionally, the image acquisition apparatus is communicatively coupled to an image energy source, wherein the image energy source is coupled in a half-fan configuration with respect to a treatment machine, and wherein the patient support is located off-isocenter with respect to the treatment machine.

Optionally, the first plurality of two-dimensional images is obtained at a same isocenter position associated with a treatment machine.

Optionally, the positioner controller is configured to generate the control signal to cause the positioner to translate the patient support at a rate that is at least 80% of its maximum speed.

Optionally, the image acquisition apparatus further includes a CT image processor configured to construct a volumetric image based on the first composite image.

Optionally, the image processing unit is also configured to obtain a volumetric image based on the first plurality of two-dimensional images.

Optionally, the imaging controller is also configured to control a radiation source to deliver radiation continuously for at least 2 seconds.

Optionally, the imaging controller is also configured to control a radiation source to deliver radiation in pulses.

Optionally, the image processing unit is configured to obtain couch positions for the patient support or imager positions for the imager, and utilize the couch positions and/or the imager positions to arrange the two-dimensional images with respect to a reference coordinate for the composite image.

Optionally, the image processing unit is also configured to obtain meta data for the respective two-dimensional images, and utilize the meta data to map the two-dimensional images to a reference coordinate for the composite image.

An imaging method performed by an image acquisition apparatus, includes: generating a control signal by a positioner controller that is communicatively coupled to a positioner, wherein the control signal is generated to cause the positioner to rectilinearly translate a patient support relative to an imager, and/or to rectilinearly translate the imager relative to the patient support; operating the imager to generate a first plurality of two-dimensional images for a patient while the patient is supported by the patient support, and while the positioner rectilinearly translates the patient support and/or the imager; and arranging, by an image processing unit, the two-dimensional images relative to each other to obtain a first composite image.