Systems and methods for imaging large field-of-view objects

Abstract

An imaging apparatus and related method comprising a detector located a distance from a source and positioned to receive a beam of radiation in a trajectory; a detector positioner that translates the detector to an alternate position in a direction that is substantially normal to the trajectory; and a beam positioner that alters the trajectory of the radiation beam to direct the beam onto the detector located at the alternate position.

Description

andAs discussed above, an x-ray scanning system is disclosed. The scanning system may include various embodiments which may include portions as discussed above and herein either separately or in combination. For example, FIG. 17 is a schematic diagram showing an x-ray scanning system 10 in accordance with one embodiment of the invention. The x-ray scanning system 10 includes a gantry 11′ secured to a support structure, which could be a mobile or stationary cart, a patient table, a wall, a floor, or a ceiling. As shown in FIG. 17, the gantry 11′ is secured to a mobile cart 12′ in a cantilevered fashion via a ring positioning unit 20′. In certain embodiments, the ring positioning unit 20′ translates and/or tilts the gantry 11′ with respect to the support structure to position the gantry 11′ in any number of imaging positions and orientations.

The mobile cart 12′ of FIG. 17 can optionally include a power supply, an x-ray power generator, and a computer system for controlling operation of the x-ray scanning device and for performing image processing, storage of x-ray images, or other data processing functions. In a preferred embodiment, the computer system controls the positioning unit 20′ to enable the gantry 11′ to be quickly moved to a particular user-defined position and orientation. The computer preferably has a memory that is capable of storing positioning information relating to particular gantry positions and/or orientations. This stored positioning information can be used to automatically move the gantry to a pre-defined configuration upon demand.

The mobile cart 12′ preferably also includes a display system 60′, such as a flat panel display, for displaying images obtained by the x-ray scanner. The display can also include a user interface function, such as a touch-screen controller, that enables a user to interact with and control the functions of the scanning system. In certain embodiments, a user-controlled pendant or foot pedal can control the functions of the scanning system.

It will be understood that one or more fixed units can also perform any of the functions of the mobile cart 12′.

According to one aspect, the x-ray scanning system of the invention can be used to obtain two-dimensional x-ray images of an object, such as a patient, in multiple projection planes. In the embodiment shown in FIG. 17, the gantry 11′ is a generally circular, or “O-shaped,” housing having a central opening into which an object being imaged is placed. The gantry 11′ contains an x-ray source 13′ (such as a rotating anode pulsed x-ray source) that projects a beam of x-ray radiation 15′ into the central opening of the gantry, through the object being imaged, and onto a detector array 14′ (such as a flat panel digital detector array) located on the opposite side of the gantry. The x-rays received at the detector 14′ can then be used to produce a two-dimensional image of the object using well-known techniques.

The x-ray source 13′ is able to rotate around the interior of the gantry 11′ in a continuous or step-wise manner so that the x-ray beam can be projected through the object, and through a common isocenter, at various angles over a partial or full 360 degree rotation. The detector array is also rotated around the interior of the gantry, in coordination with the rotation of the x-ray source, so that for each projection angle of the x-ray source, the detector array is positioned opposite the x-ray source on the gantry. The apparatus is thus able to obtain two-dimensional x-ray images of the targeted object in any projection plane over a partial or full 360 degree rotation.

The x-ray system of the invention can be operated in a static or in a multi-planar mode. In a static mode, a user selects a desired imaging plane in the target object, and the x-ray source and detector are rotated to the appropriate angle within the gantry. As shown in FIG. 18A, for example, the x-ray source and detector are at the top and bottom of the gantry, respectively, for acquisition of an anterior-posterior (AP) type patient image. Alternatively, or in addition, the gantry itself can be moved by positioning or tilting the gantry relative to the target object using the gantry positioning unit 20′, as shown in FIG. 27. In static mode, the x-ray scanner can acquire and display a single x-ray image of the object, or can obtain multiple images of the object, and continuously update the display with the most recent image. In a preferred embodiment, the x-ray scanner obtains multiple object images in quick succession, and displays these images in real time (e.g. 30 frames per second) in a “cinematic” mode.

To change the imaging plane of the object, the x-ray source and detector can be rotated to another angle within the gantry. As shown in FIG. 18B, for example, the source and detector rotate 90 degrees in a clockwise direction for obtaining object images in a lateral plane. Alternatively or in addition, translating or tilting the entire gantry to a second position can change the imaging plane.

In multi-planar mode, the x-ray scanner obtains a series of images from multiple projection planes in rapid succession. The imaging system advantageously permits quasi-simultaneous multi-planar imaging using a single radiation source. As shown in FIG. 18A, for example, the x-ray source 13′ and detector 14′ are initially positioned at the top and bottom of the gantry respectively and acquire a first x-ray image of the target object, which in this case is an anterior-posterior (AP) view of a patients spine. The source and detector then rotate 90 degrees clockwise within the fixed gantry to obtain a second x-ray image shown in FIG. 18B, which is a lateral view of the spine. These bi-planar AP/lateral images are obtained quasi-simultaneously, as there is no appreciable delay between the acquisition of the two images, other than the time it takes for the source to rotate between projection angles on the gantry. Additional AP/lateral images can be obtained and continuously updated by alternatively rotating the source and detector between two projection angles, such as the two perpendicular projections shown FIGS. 18A and 18B. In a preferred embodiment, however, quasi-simultaneous multi-planar images are obtained and updated in real time by continuously rotating the source and detector over a full 360 degree rotation, obtaining images at desired rotational increments. As shown in FIGS. 18A and 18B, for example, four bi-planar images, including two AP images, and two lateral images, can be obtained in quick succession during a single 360 degree rotation of the source and detector. These images can be displayed individually, sequentially, side-by-side, or in any desired manner.

A further illustration of the quasi-simultaneous multi-planar imaging of the invention is shown in FIG. 19. Here, a rotatable detector array is shown capturing quasi-simultaneous x-ray images of ten incremental projection planes over a full 360 degree rotation. These images are captured continuously, or in a step wise fashion. They can be displayed individually, side-by-side, sequentially in a cinematic mode, or in any desired manner.

As shown in FIG. 17, the x-ray source 13′ and detector array 14′ can be secured to a C-shaped motorized rotor assembly 33′. The rigid rotor assembly maintains the source and detector opposed to one another while the entire rotor assembly rotates inside the gantry. As shown in FIGS. 20 and 21A, the rotor assembly 33′ also includes a motor 31′ and drive wheel 32′ for driving the rotor assembly around the interior of the gantry. As shown in FIG. 21A, the interior side walls of the gantry include curved rails 27′ extending in a continuous loop around the interior of the gantry. The drive wheel 32′ of the rotor assembly 33′ contacts the curved rail 27′ of the gantry, and uses the tall to drive the rotor assembly around the interior of the gantry. A rotary incremental encoder can be used to precisely measure the angular position of the rotor assembly within the gantry. The incremental encoder can be driven by a friction wheel that tolls on a concentric rail located within the sidewall of the gantry. The rotor assembly 33′ also includes bearings 29′, which mate with the curved rails 27′ of the gantry to help guide the rotor assembly 33′ as it rotates inside the gantry. The interior of the gantry ring 11′ can include a slip ring 102′ that maintains electrical contact with the rotor assembly 33′ to provide the power (e.g., from external power source 101′) needed to operate the x-ray source/detector and to rotate the entire assembly within the gantry frame. The slip ring can also be used to transmit control signals to the rotor, and x-ray imaging data from the detector to a separate processing unit located outside the gantry, such as the mobile can 12′ of FIG. 17. Any or all of the functions of the slip ring could be performed by other means, such as the cable management system described below.

Although the rotor assembly of the preferred embodiment is a C-shaped rotor, it will be understood that other rotor configurations, such as O-shaped rotors, could also be employed. In addition, the x-ray source and detector could rotate independently of one another using separate mechanized systems. Moreover, the x-ray source alone can rotate, with multiple detector arrays located at fixed positions around the interior of the gantry.

The detector array 14′ shown in FIG. 20 comprises a two-dimensional flat panel solid-state detector array. It will be understood, however, that various detectors and detector arrays can be used in this invention, including any detector configurations used in typical diagnostic fan-beam or cone-beam imaging systems, such as C-arm fluoroscopes. A preferred detector is a two-dimensional thin-film transistor x-ray detector using scintillator amorphous-silicon technology.

For large field-of-view imaging, the detector 14′ can be translated to, and acquire imaging data at, two or more positions along a line or arc opposite the x-ray source 13′, such as via a motorized detector rail and bearing system. Examples of such detector systems are described in commonly owned U.S. Provisional Application No. 60/366,062, filed Mar. 19, 2002, the entire teachings of which are incorporated herein by reference.

FIGS. 22A-22E illustrate another embodiment of an x-ray imaging apparatus having a cable management system for rotating an x-ray source and detector array 360° around the interior of the gantry ring. In this embodiment, the power for the x-ray source/detector system, as well as for rotating the x-ray source/detector within the gantry, is provided (at least in part) by a cable harness 36′ containing one or more cables. The cable harness 36′ can also be used to transmit signals and data between the x-ray source/detector and an external processing unit.

The cable harness 36′ is preferably housed in a flexible, linked cable carrier 37′. One end of the carrier 37′ is fixed to a stationary object, such as the gantry 11′ or the cart. The other end of the carrier 37′ is attached to the motorized rotor assembly 33′ which contains the x-ray source 13′ and detector 14′. In the example shown in FIGS. 22A-22E, the rotor 33′ starts at an initial position with the x-ray source 13′ at the bottom of the gantry and the detector 14′ at the top of the gantry (i.e. rotor angle=0°) as shown in FIG. 22A. The rotor 33′ then rotates in a clockwise direction around the interior of the gantry, as illustrated in FIG. 22B (90°° rotation), FIG. 22C (180°° rotation), FIG. 22D (270°° rotation), and FIG. 22E (360°° rotation). In FIG. 22D, the rotor 33′ has made a full 360°° rotation around the interior of the gantry 11′, and the rotor is again at the initial position with the x-ray source 13′ at the bottom of the gantry, and the detector 14′ at the top of the gantry. During the rotation, the cable carrier 37′ remains connected to both the rotor 33′ and gantry 11′, and has sufficient length and flexibility to permit the rotor 33′ to easily rotate at least 360° from the start position. To perform another 360° rotation, the rotor 33′ can rotate counterclockwise from the end position of the prior rotation (e.g. rotor angle=360° in FIG. 22E) until the rotor 33′ returns to the initial position of FIG. 22A. For continuous rotation, this process can repeat itself indefinitely with the rotor making full 360° rotations in alternatively clockwise and counterclockwise directions.

As shown in FIGS. 23-27, the ring positioning unit 20′ preferably enables the gantry 11′ to translate and/or tilt with respect to the support structure. FIG. 23 shows a gantry ring positioning unit in a parked mode. FIG. 24 shows the translational motion of the positioning unit in a lateral direction relative to the cart. FIG. 25 shows translational movement of the positioning unit in a vertical direction relative to the cart. FIG. 26 shows the tilting motion of the positioning unit relative to the cart. In FIG. 27, the entire gantry assembly is illustrated in fully extended lateral, vertical, and tilt positions. The ability of the gantry to translate and tilt in multiple directions allows for the acquisition of x-ray images in any desired projection plane, without having to continuously reposition the patient or the system. As discussed above, a control system can automatically move the gantry to a desired position or orientation, including to user-defined positions and orientations stored in computer memory, for x-ray imaging procedures. X-ray scanning devices with cantilevered, multiple-degree-of-freedom movable gantries are described in commonly owned U.S. Provisional Application No. 60/388,063, filed Jun. 11, 2002, and U.S. Provisional Application No. 60/405,098, filed Aug. 21, 2002, the entire teachings of which are incorporated herein by reference.

In the embodiments shown and described thus far, the central axis of the gantry is oriented essentially horizontally, so that an object being imaged, such as a patient, lies lengthwise in the imaging area. In other embodiments, however, the gantry may be aligned so that its central axis extends at virtually any angle relative to the patient or object being imaged. For instance, the central axis of the gantry can be aligned essentially vertically, as shown in FIG. 28. Here, the central opening of the gantry is concentric with the “cylinder” formed by the torso of a standing or sitting human. The entire imaging procedure can thus be performed while the patient remains in a standing or sitting position. Also, in addition to the medical procedures described, the vertical axis gantry may be useful for imaging other objects in which it is convenient to image the object while it is aligned in a standing or vertical orientation.

An imaging device of the present invention could also comprise a substantially O-shaped gantry that includes a segment that at least partially detaches from the gantry ring to provide an opening or “break” in the gantry ring through which the object to be imaged may enter and exit the central imaging area of the gantry ring in a radial direction. An advantage of this type of device is the ability to manipulate the x-ray gantry around the target object, such as a patient, and then close the gantry around the object, causing minimal disruption to the object, in order to perform x-ray imaging. Examples of “breakable” gantry devices for x-ray imaging are described in commonly-owned U.S. patent application Ser. No. 10/319,407, filed Dec. 12, 2002, the entire teachings of which are incorporated herein by reference.

It will also be understood that although the embodiments shown here include x-ray imaging devices having O-shaped gantries, other gantry configurations could be employed, including broken ring shaped gantries having less than full 360 degree rotational capability.

While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

For instance, although the particular embodiments shown and described herein relate in general to x-ray imaging applications, it will further be understood that the principles of the present invention may also be extended to other medical and non-medical imaging applications, including, for example, magnetic resonance imaging (MRI), positron emission tomography (PET), single photon emission computed tomography (SPECT), ultrasound imaging, and photographic imaging.

As discussed above, an x-ray scanning system is disclosed. The scanning system may include various embodiments which may include portions as discussed above and herein either separately or in combination. For example, FIG. 29 is a schematic diagram showing an x-ray scanning system 10, such as a computerized tomographic (CT) x-ray scanner, in accordance with one embodiment of the invention. The x-ray scanning system 10 generally includes a gantry 11″ secured to a support structure, which could be a mobile or stationary cart, a patient table, a wall, a floor, or a ceiling. As shown in FIG. 29, the gantry 11″ is secured to a mobile cart 12″ in a cantilevered fashion via a ring positioning unit 20″. In certain embodiments, the ring positioning unit 20″ enables the gantry 11″ to translate and/or rotate with respect to the support structure, including, for example, translational movement along at least one of the x-, y-, and z-axes, and/or rotation around at least one of the x- and y-axes. X-ray scanning devices with a cantilevered, multiple-degree-of-freedom movable gantry are described in commonly owned U.S. Provisional Applications 60/388,063, filed Jun. 11, 2002, and 60/405,098, filed Aug. 21, 2002, the entire teachings of which are incorporated herein by reference.

The mobile cart 12″ of FIG. 29 can optionally include a power supply, an x-ray power generator, a computer system for controlling operation of the x-ray scanning device and for performing image processing, tomographic reconstruction, or other data processing functions, and a display system, which can include a user interface for controlling the device. It will be understood that one or more fixed units can also perform these functions.

The gantry 11″ is a generally circular, or “O-shaped,” housing having a central opening into which an object being imaged is placed. The gantry 11″ contains an x-ray source 13″ (such as a rotating anode pulsed x-ray source) that projects a beam of x-ray radiation 15″ into the central opening of the gantry, through the object being imaged, and onto a detector array 14″ located on the opposite side of the gantry. The x-ray source 13″ is also able to rotate 360 degrees around the interior of the gantry 11″ in a continuous or step-wise manner so that the x-ray beam can be projected through the object at various angles. At each projection angle, the x-ray radiation beam passes through and is attenuated by the object. The attenuated radiation is then detected by a detector array opposite the x-ray source. Preferably, the gantry includes a detector array that is rotated around the interior of the gantry in coordination with the rotation of the x-ray source so that, for each projection angle, the detector array is positioned opposite the x-ray source on the gantry. The detected x-ray radiation from each of the projection angles can then be processed, using well-known reconstruction techniques, to produce a two-dimensional or three-dimensional object reconstruction image.

In a conventional CT x-ray scanning system, the object being imaged (typically a patient) must enter the imaging area lengthwise from either the front or rear of the gantry (i.e. along the central axis of the gantry opening). This makes it difficult, if not impossible, to employ CT x-ray scanning during many medical procedures, such as surgery, despite the fact that this is where CT scanning applications may be most useful. Also, the conventional CT x-ray scanner is a relatively large, stationary device having a fixed bore, and is typically located in a dedicated x-ray room, such as in the radiology department of a hospital. CT scanning devices are generally not used in a number of environments, such as emergency departments, operating rooms, intensive care units, procedure rooms, ambulatory surgery centers, physician offices, and on the military battlefield. To date, there is not a small-scale or mobile CT scanning device, capable of producing high-quality images at relatively low cost, which can be easily used in various settings and environments, including during medical procedures.

In one aspect, the present invention relates to an improvement on the conventional design of an x-ray imaging device which overcomes these and other deficiencies. In particular, as shown in FIG. 29, the O-shaped gantry 11″ includes a segment 16″ that at least partially detaches from the gantry ring to provide an opening or “break” in the gantry ring through which the object to be imaged may enter and exit the central imaging area of the gantry ring in a radial direction. In FIG. 29, for instance, a segment 16″ of the gantry 11″ is secured to the gantry via a hinge 17″ which allows the segment to swing out like a door from a fully closed position (see FIG. 2B) to a fully open position (see FIG. 30A). The object being imaged (for instance, a patient) can then enter the gantry from the open side (as opposed to from the front or rear side of the gantry, as in conventional systems), and the hinged segment can then be reattached to fully enclose the object within the gantry ring. (Alternatively, or in addition, the gantry in the open position can be moved towards the object in a lateral direction to position the object within the imaging area, and then the open segment can close around the object.)

In addition to the hinged door embodiment of FIGS. 29, 30A, and 30B, various other embodiments of the of the gantry assembly are shown in FIGS. 31-35. In each of these systems, a segment of the gantry at least partially detaches from the gantry ring to provide an opening or “break” in the gantry ring through which the object to be imaged may enter and exit the central imaging area of the gantry ring in a radial direction, and wherein the segment can then be reconnected to the gantry to perform 2D x-ray or 3D tomographic x-ray imaging.

In FIG. 31, for example, a gantry segment 16″ is fully detachable from the fixed portion of the gantry ring 11″, and can then be reattached to perform an x-ray imaging process. Similarly, in FIG. 32, the gantry segment 16″ fully detaches from the ring to form an opening. In this case, however, the detached segment “piggy backs” on the gantry. This embodiment may include a linkage apparatus which allows the door 16″ to detach away from the ring 11″ and, while maintaining attached to the ring via the linkage apparatus, swing upwards and circumferentially onto the top of the fixed portion of the gantry ring 11″.

FIG. 33 illustrates yet another embodiment, where the gantry opens by telescoping the detachable segment 16″ with the fixed gantry ring 11″. In one embodiment, a the detachable segment 16″ can be attached to the gantry ring 11″ with alignment pins. A release mechanism releases the pins, and the sidewalls of the segment 16″ translate outward relative to the gantry ring, thus allowing the segment 16″ to telescope over the fixed upper portion of the gantry ring 11″.

In FIG. 34, the gantry opens by lifting a top segment 16″ of the gantry off the ring, preferably via a vertical lift mechanism 18″ which can be located on the cart 12″.

FIG. 35 shows yet another embodiment with a pivoted gantry segment 16″. This is similar to the hinged design of FIG. 29, except here the detachable segment is hinged to the gantry at the side of the gantry opposite the opening, so that the entire top half of the gantry lifts up to access the interior imaging area.

In any of these embodiments, the detachable gantry segment preferably includes a mechanism for securing the segment in place in a closed gantry configuration, yet also permits the segment to be easily detached to open or “break” the gantry ring.

In FIGS. 36-38, for example, a latching assembly 18″ is used to secure or lock the hinged gantry segment 16″ in place when the gantry is closed (for instance, during an x-ray imaging process). In a locked state, the hinged segment 16″ is not permitted to pivot out from the closed gantry ring, and the x-ray source 13″ and detector 14″ can rotate 360 degrees around the inside of the closed gantry ring. However, the latching assembly 18″ can also be easily unlocked, which permits the hinged segment 16″ to be swung open.

In FIG. 36, for instance, the latching mechanism 18″, which includes handle 21″, linking members 22″, 23″, and upper and lower latches 24″, 25″, is in an unlocked position, while the hinged gantry segment 16″ is in a fully open position. In FIG. 37, the gantry segment 16″ is now in a closed position, but the latching mechanism 18″ is still unlocked. As shown in FIG. 38, the latching mechanism 18″ is locked by pulling handle 21″ down into a locked position. The latching mechanism 18″ can be easily unlocked by pushing the handle up to an unlocked position, and the hinged gantry segment 16″ can then swing open.

In FIG. 39, the latching mechanism 18″ is shown by way of an “end on” view of the interior of the open gantry segment 16″. As shown here, spring-loaded alignment pins 34″ on the hinged gantry segment 16″ are driven into bushings 35″ (see FIG. 36) on the fixed gantry 11″ via a wedge-shaped latches 24″, 25″, causing the gantry segment 16″ to be secured to the fixed gantry portion 11″. The wedge-shaped latches 24″,25″ are driven by a linkage members 22″, 23″ connected to the handle 21″ operated by a user. Also shown in this figure is a slip ring 26″, which maintains electrical contact with the motorized rotor assembly 33″ (see FIG. 40), and a curved rail 27″, which guides the rotor assembly 33″ as it rotates around the interior of the gantry 11″, as will be described in further detail below. When the gantry is in a closed and locked position, the slip ring 26″ and curved rail 27″ of the detachable segment 16″ align with the slip ring and curved rail of the fixed gantry, so that the motorized rotor assembly 30″ (see FIG. 40) which carries the x-ray source and detector array can properly rotate within the gantry. During operation, the slip ring 26″ preferably maintains electrical contact with the rotor assembly 30″, and provides the power needed to operate the x-ray source/detector system, and to rotate the entire assembly within the gantry frame. The slip ring 26″ can also be used to transmit x-ray imaging data from the detector to a separate processing unit located outside the gantry, such as in the mobile cart 12″ of FIG. 29.

FIGS. 43A-43E illustrate another embodiment of an x-ray imaging apparatus having a cable management system for rotating an x-ray source and detector array 360° around the interior of the gantry ring. In this example, the power for the x-ray source/detector system, as well as for rotating the x-ray source/detector within the gantry, is provided (at least in part) by a cable harness 36″ containing one or more cables, in much the same manner as the slip ring described above. The cable harness 36″ can also be used to transmit signals and data between the x-ray source/detector and an external processing unit.

The cable harness 36″ is preferably housed in a flexible, linked cable carrier 37″. One end of the carrier 37″ is fixed to a stationary object, such as the gantry 11″ or the cart. The other end of the carrier 37″ is attached to the motorized rotor assembly 33″ which contains the x-ray source 13″ and detector 14″. In the example shown in FIGS. 43A-43E, the rotor 33″ starts at an initial position with the x-ray source 13″ at the top of the gantry and the detector 14″ at the bottom of the gantry (i.e. rotor angle=0°) as shown in FIG. 43A. The rotor 33″ then rotates in a clockwise direction around the interior of the gantry, as illustrated in FIG. 43B (90° rotation), FIG. 43C (180° rotation), FIG. 43D (270° rotation), and FIG. 43E (360° rotation). In FIG. 43E, the rotor 33″ has made a full 360° rotation around the interior of the gantry 11″, and the rotor is again at the initial position with the x-ray source 13″ at the top of the gantry, and the detector 14″ at the bottom of the gantry. During the rotation, the cable carrier 37″ remains connected to both the rotor 33″ and gantry 11″, and has sufficient length and flexibility to permit the rotor 33″ to easily rotate at least 360° from the start position. To perform another 360° rotation, the rotor 33″ can rotate counterclockwise from the end position of the prior rotation (e.g. rotor angle=360° in FIG. 43E) until the rotor 33″ returns to the initial position of FIG. 43A. For continuous rotation, this process can repeat itself indefinitely with the rotor making full 360° rotations in alternatively clockwise and counterclockwise directions.

FIGS. 39 and 40 show one example of a rail and bearing mechanism for rotating the x-ray source 13″ and detector 14″ inside the gantry for performing two-dimensional and/or three-dimensional x-ray imaging procedures. As shown in FIG. 40″, a motorized rotor assembly 33″ includes the x-ray source 13″ and the detector array 14″ held within a rigid frame 30″ designed to maintain a constant spacing between the source and detector as the rotor assembly rotates inside the x-ray gantry. (Note that the motorized rotor is generally c-shaped, with an open region at least as large as the detachable segment 16″ of the gantry frame, so that the rotor assembly does not obstruct the opening of the gantry.) The rotor assembly 30″ also includes a motor 31″ and gear 32″ for driving the rotor assembly around the interior of the gantry. As shown in FIG. 39, the interior side walls of the gantry include curved rails 27″ which extend in a continuous loop around the interior of the gantry when the gantry is in a closed position. The gear 32″ of the rotor assembly 30″ contacts the curved rail 27″ of the gantry, and uses the rail to drive the rotor assembly around the interior of the gantry. The rotor assembly 30″ also includes curve rail carriages 29″, which mate with the curved rails 27″ of the gantry to help guide the rotor assembly 30″ as it rotates inside the gantry.

The detector array 14″ shown in FIG. 40 comprises three two-dimensional flat panel solid-state detectors arranged side-by-side, and angled to approximate the curvature of the gantry ring. It will be understood, however, that various detectors and detector arrays can be used in this invention, including any detector configurations used in typical diagnostic fan-beam or cone-beam CT scanners. A preferred detector is a two-dimensional thin-film transistor x-ray detector using scintillator amorphous-silicon technology.

For large field-of-view imaging, a detector 14″ can be translated to, and acquire imaging data at, two or more positions along a line or arc opposite the x-ray source 13″, such as via a motorized detector rail and bearing system. Examples of such detector systems are described in commonly owned U.S. Provisional Application 60/366,062, filed Mar. 19, 2002, the entire teachings of which are incorporated herein by reference.

FIGS. 41A, 41B, and 41C show an embodiment of the scanner assembly 10 which is used for a medical imaging procedure. FIG. 41A, shows a patient 40″ lying on a table 41″ next to a mobile x-ray imaging apparatus 10 with a hinged segment 16″ of the gantry ring 11″ is fully open. The entire apparatus can then be moved in a lateral direction towards the patient (alternatively, or in addition, the patient can be moved towards the imaging apparatus), so that a region of interest of the patient is aligned within the x-ray gantry 11″, as shown in FIG. 41B. Finally, as shown in FIG. 41C, the hinged segment 16″ of the gantry 11″ is closed, fully enclosing the patient within the gantry ring, and an x-ray imaging procedure is performed.

In the embodiments shown and described thus far, the central axis of the gantry is oriented essentially horizontally, so that an object being imaged, such as a patient, lies lengthwise in the imaging area. In other embodiments, however, the gantry may be aligned so that its central axis extends at virtually any angle relative to the patient or object being imaged. For instance, the central axis of the gantry can be aligned essentially vertically, as shown in FIG. 42. Here, the central opening of the gantry is concentric with the “cylinder” formed by the torso of a standing or sitting human. As in the previous embodiments, the gantry includes a segment 16″ that at least partially detaches from the gantry ring 11″ to provide an opening or “break” in the gantry ring through which the object to be imaged may enter and exit the central imaging area of the gantry ring in a radial direction. The patient can enter the gantry via this opening in a standing or sitting position, and the segment can be easily re-attached for an imaging procedure. The entire imaging procedure can thus be performed while the patient remains in a standing or sitting position. Also, in addition to the medical procedures described, the vertical axis gantry may be useful for imaging other objects in which it is convenient to image the object while it is aligned in a standing or vertical orientation.

The x-ray imaging apparatus described herein may be advantageously used for two-dimensional and/or three-dimensional x-ray scanning. Individual two-dimensional projections from set angles along the gantry rotation can be viewed, or multiple projections collected throughout a partial or full rotation may be reconstructed using cone or fan beam tomographic reconstruction techniques.

While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

For instance, although the particular embodiments shown and described herein relate in general to computed tomography (CT) x-ray imaging applications, it will further be understood that the principles of the present invention may also be extended to other medical and non-medical imaging applications, including, for example, magnetic resonance imaging (MRI), positron emission tomography (PET), single photon emission computed tomography (SPECT), ultrasound imaging, and photographic imaging.

Also, while the embodiments shown and described here relate in general to medical imaging, it will be understood that the invention may be used for numerous other applications, including industrial applications, such as testing and analysis of materials, inspection of containers, and imaging of large objects.

The detector arrays described herein include two-dimensional flat panel solid-state detector arrays. It will be understood, however, that various detectors and detector arrays can be used in this invention, including any detector configurations used in typical diagnostic fan-beam or cone-beam imaging systems, such as C-arm fluoroscopes. A preferred detector is a two-dimensional thin-film transistor x-ray detector using scintillator amorphous-silicon technology.

While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. For instance, although the particular embodiments shown and described herein relate in general to computed tomography (CT) x-ray imaging applications, it will further be understood that the principles of the present invention may also be extended to other medical and non-medical imaging applications, including, for example, magnetic resonance imaging (MRI), positron emission tomography (PET), single photon emission computed tomography (SPECT), ultrasound imaging, and photographic imaging.

Also, while the embodiments shown and described here relate in general to medical imaging, it will be understood that the invention may be used for numerous other applications, including industrial applications, such as testing and analysis of materials, inspection of containers, and imaging of large objects.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

1. A method of operating an image apparatus, comprising:

positioning a detector to image at least a portion of a volume configured to hold an object larger than a field-of-view of the detector;

utilizing a detector positioner to translate the detector to multiple positions relative to the volume;

positioning a beam such that a trajectory of the beam follows the path of the translating detector; and

moving a rotor within a gantry such that the beam follows the path of the translating detector;

wherein the detector and a beam source that emits the beam are movably mounted to the rotor.

2. A method of operating an image apparatus, comprising:

positioning a detector to image at least a portion of a volume configured to hold an object larger than a field-of-view of the detector;

utilizing a detector positioner to translate translating the detector to multiple positions relative to the volume;

positioning a beam such that a trajectory of the beam follows the path of the translating detector; and

driving a beam source with a motor to pivotally move the beam source mounted on a swiveling source mount;

wherein the beam source is mounted to a source frame having at least two separated walls and a series of lateral members extending between the at least two separated walls and the swiveling source mount to pivotally hold the source relative to the source frame.

3. A method of operating an image apparatus, comprising:

positioning a detector to image at least a portion of a volume configured to hold an object larger than a field-of-view of the detector;

utilizing a detector positioner to translate translating the detector to multiple positions relative to the volume;

positioning a beam such that a trajectory of the beam follows the path of the translating detector; and

moving a detector carriage relative to a detector frame having at least two separated walls and a series of lateral members extending between the at least two separated walls;

wherein the detector is mounted to the detector carriage to hold the detector and move the detector.

4. The method of claim 1, further comprising moving separately all of the beam source, the detector, and the rotor while obtaining images of the object.

5. The method of claim 1, further comprising rotating the rotor within an interior cavity of the gantry over a 360° 360 degree circumference of the gantry.

6. The method of claim 1, further comprising moving a source housing within a source stage to move the source housing about a central point to direct the beam onto the detector.

7. The method of claim 1, wherein the beam is projected by the beam source, and the trajectory of the beam is altered by tilting the beam source.

8. The method of claim 1, wherein translating the detector further includes translating the detector along an arc.

9. The method of claim 1, wherein translating the detector further includes translating the detector along a line.

10. A method of operating an image apparatus, comprising:

positioning a detector to image at least a portion of a volume configured to hold an object larger than a field-of-view of the detector, including:

positioning the detector at a first position within a gantry to image a first portion of the object;

positioning a beam such that the beam is detected by the detector at the first position;

moving the detector to a second position within the gantry to image the first portion of the object;

moving the beam such that the beam is with the detector to be detected by the detector at the second position; and

moving a rotor within the gantry from a first angle to a second angle;

wherein both of the detector and a beam source that emits the beam are moveably mounted to the rotor.

11. The method of claim 10, further comprising:

moving all of the beam source, the detector, and the rotor to minimize exposure of the object to radiation while obtaining images of the object.

12. The method of claim 10, further comprising:

moving separately all of the beam source, the detector, and the rotor while obtaining images of the object.

13. The method of claim 10, wherein moving the detector to the second position within the gantry includes moving the detector along an arc.

14. The method of claim 10, wherein moving the detector to the second position within the gantry includes moving the detector along a line.

15. A method of operating an imaging apparatus, comprising:

positioning an object within an o-shaped gantry;

rotating a rotor carrying a source and a detector within an interior cavity of the gantry about the object;

positioning the detector to image a portion of the object that is larger than a field-of-view of the detector;

translating the detector to multiple positions relative to the object; and

positioning a beam from the source such that a trajectory of the beam follows the path of the translating detector.

16. The method of claim 15, further comprising utilizing a detector positioner to translate the detector to the multiple positions.

17. The method of claim 15, wherein the detector is translated along one of an arc or along a line.

18. The method of claim 15, further comprising tilting the source at a focal point to change the trajectory of the beam to follow the path of the translating detector.