X-ray backscatter imaging has been used for detecting concealed contraband, such as drugs, explosives, and weapons, since the late 1980's. Unlike traditional transmission x-ray imaging that creates images by detecting the x-rays penetrating through an object, backscatter imaging uses reflected or scattered x-rays to create the image. The basic principle is shown in
In the last few years, handheld x-ray backscatter imaging devices have been introduced into the market, enabling an operator to inspect suspect vehicles, packages, or other objects conveniently. These devices have been designed to be relatively compact and lightweight, allowing them to be easily operated for extended periods of time.
In an embodiment, an x-ray imaging system includes a movable x-ray scanning module configured to generate a sweeping beam of x-rays, a positioning arm, and a detector panel. The detector panel is coupled to or configured to be coupled to the positioning arm. The positioning arm is configured to allow an operator to position the detector panel relative to the movable x-ray scanning module and with an orientation for receiving x-rays from a target resulting from the sweeping beam of x-rays being incident at the target or transmitted through the target.
In some embodiments, the detector panel is an auxiliary detector panel. The movable x-ray scanning module includes a primary detector oriented to receive backscatter x-rays from the target resulting from the sweeping beam of x-rays being incident at the target. In some embodiments, the primary detector is a panel.
In some embodiments, the primary detector is operably coupled to a primary detector module that is configured to output a primary x-ray image signal. The primary x-ray image signal enables a processor to form a primary x-ray image. The auxiliary detector panel is operably coupled to an auxiliary detector module that is configured to output an auxiliary x-ray image signal responsive to the auxiliary detector panel's receiving x-rays from a target resulting from the sweeping beam of x-rays being incident at the target or transmitted through the target.
In some embodiments, the x-ray imaging system further includes a processor operably coupled to at least one of the primary detector module and the auxiliary detector module. The processor is configured to form an x-ray image as a function of the primary x-ray image signal, auxiliary x-ray image signal, or combination thereof.
In some embodiments, the positioning arm has a mechanical relationship with the moveable x-ray scanning module selected from a group including: coupled to the movable x-ray scanning module; detachable from the x-ray scanning module; or independent from the x-ray scanning module.
In some embodiments, the detector panel is either (i) non-planar and (ii) flexible.
In some embodiments, x-ray imaging system further includes either a location or orientation sensor located in the positioning arm, detector panel, or movable x-ray scanning module. The either location or orientation sensor is configured to output a signal that can be used by a processor to determine a relative location or orientation of the detector panel with respect to the movable x-ray scanning module.
In some embodiments, the positioning arm further includes multiple telescoping sections. The multiple telescoping sections are sufficiently stiff in a fully extended state to support the detector panel in an operator-defined position and orientation.
In some embodiments, the positioning arm is adjustable along its length.
In some embodiments, the detector panel in a coupled arrangement with the positioning arm is configured to be positioned by the operator to receive either (i) transmission x-rays through the target, or (ii) backscatter, side scatter, or forward scatter x-rays from the target.
In some embodiments, the x-ray imaging system further includes (i) one or more electrical cable configured to connect the detector panel operably to a processor of the x-ray imaging system or (ii) a wireless link subsystem configured to connect the detector panel operably to the processor of the x-ray imaging system via a wireless communications protocol.
In an embodiment, the detector panel comprises one or more scintillator volumes configured to be oriented along a scan axis of a scanning beam of x-rays to receive x-rays from the scanning beam transmitted through a target. The one or more scintillator volumes configured to produce scintillation photons responsive to receiving the x-rays. The detector panel further includes multiple ribbons of wavelength-shifting fibers (WSFs) optically coupled to the one or more scintillator volumes along the scan axis via a spatial periodic adjacency of the multiple ribbons to the scan axis. The multiple ribbons configured to receive scintillation photons from the one or more scintillator volumes via the spatial periodic adjacency as the scanning beam of x-rays scans over the scan axis. The detector panel further includes a respective photodetector coupled to an end of each respective ribbon of the plurality of ribbons. Each respective photodetector is configured to detect the scintillation photons carried by the respective ribbon and to produce a respective signal responsively. The detector panel further includes a signal combiner configured to combine, selectively, respective signals from ribbons of the multiple ribbons, for positions of the scanning beam along the scan axis, to create a combined signal representing a scan of the target with enhanced spatial resolution.
In some embodiment, the detector module includes a light detection structure. The light detection structure includes a tubular support structure having a curved outer surface, and multiple ribbons of wavelength-shifting fibers (WSFs) wrapped around the curved outer surface in a spatially periodic, substantially helical pattern. The multiple ribbons of WSFs being configured to carry light to be detected at respective ends of respective ribbons of the multiple ribbons.
In some embodiments, detector module comprises a scintillator volume having an entrance surface and an exit surface. The entrance surface is configured to receive incident x-rays. The scintillator volume is configured to emit scintillation light responsive to the incident x-rays. The exit surface is configured to pass a portion of the incident x-rays that traverse a thickness of the scintillator volume between the entrance surface and the exit surface.
The detector panel further includes a first set of light guides optically coupled to the entrance surface of the scintillator volume and a second set of light guides optically coupled to the exit surface of the scintillator volume. The detector panel further includes a first photodetector optically coupled to an end of the first set of light guides and configured to output a first signal responsive to scintillation light from the scintillator volume. The detector panel further includes a second photodetector optically coupled to an end of the second plurality of light guides and configured to output a second signal responsive to scintillation light from the scintillator volume. The detector panel further includes a spectrum analyzer configured to receive the first and second signals responsive to the scintillation light from the scintillator volume and to determine a characteristic of an energy spectrum of the incident x-rays based on the first and second signals.
In some embodiments, the x-ray imaging system, further includes a detector structure configured for use with the scanning beam of x-rays, the detector panel, and a detector module that is configured to output an x-ray image signal responsive to the detector panel's receiving x-rays from a target resulting from the sweeping beam of x-rays being incident at the target. The detector structure includes multiple ribbons of wavelength-shifting fibers (WSF) optically coupled to one or more layers of scintillator volumes. The scintillator volumes are arranged to optically couple to the WSF ribbons in a repeating pattern along one or more axes of the detector. The detector structure further includes a photodetector coupled to one or more ends of each of the ribbons for detecting scintillation photons. The detector structure further includes a combiner configured to combine the signals from one or more of the ribbons for each orientation of the scanning beam to create a combined signal for each beam orientation, and a processor configured to create an image from the combined signal.
In some embodiments, the x-ray imaging system further includes a light detection structure including a plurality of scintillator volumes configured to be oriented spaced from each other and in a spatially periodic form along a scan axis of a scanning beam of x-rays to receive x-rays from the scanning beam transmitted through a target. The plurality of scintillator volumes are further configured to produce scintillation photons responsive to receiving the x-rays. The system further includes a wavelength-shifting fiber (WSF) ribbon optically coupled to the plurality of scintillator volumes along the scan axis. The ribbons are configured to receive scintillation photons from the plurality of scintillator volumes via the optical coupling as the scanning beam of x-rays scans over the scan axis.
In an embodiment, a detector panel includes a housing made of a flexible material. The housing defines a light-capturing cavity and preventing ambient light from entering the light-capturing cavity. The panel further includes at least one scintillation screen residing within the light-capturing cavity of the housing, the combination of the housing and the at least one scintillation screen being flexible.
In an embodiment, the housing includes or defines a coupling member that enables the detector panel to be coupled to a positioning arm or to a complementary coupling member of the positioning arm or other structure.
In an embodiment, the positioning arm is telescoping, flexible, or foldable.
In an embodiment, the housing has a port for outputting a signal, and the detector panel further includes a detector module configured to output an x-ray image signal responsive to receiving x-rays at the at least one scintillation screen from a target resulting from the sweeping beam of x-rays being incident at a target, such that an x-ray image of the target can be formed using the x-ray image signal.
In an embodiment, the detector panel further includes at least one location or orientation sensor located in the housing configured to determine a location or orientation of the detector panel relative to a source of a sweeping beam of x-rays.
The foregoing will be apparent from the following more particular description of example embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments.
A description of example embodiments follows.
Acquiring x-ray images of targets is aided by backscatter detectors, however, many targets do not allow for easy accessibility of such a backscatter detector. In view of this limitation, disclosed herein is an x-ray imaging system having a maneuverable detector panel able to be positioned around targets that traditional x-ray imaging systems would not allow. In an embodiment, the x-ray imaging system includes a movable x-ray scanning module configured to generate a sweeping beam of x-rays, a positioning arm, and a detector panel coupled to or configured to be coupled to the positioning arm. The positioning arm is configured to allow an operator to position the detector panel relative to the movable x-ray scanning module and with an orientation for receiving x-rays from a target resulting from the sweeping beam of x-rays being incident at the target or transmitted through the target.
Performance enhancement of handheld backscatter x-ray imaging systems has been achieved by optionally increasing the area of the backscatter detectors. An example of a 120 kV backscatter x-ray imaging system is shown in
However, in connection with embodiments described herein that employ a transmission detector with a sweeping x-ray beam, the transmission image obtained with a sweeping beam can be improved by using, for example, the approaches described in PCT Pat. App. Pub. No. WO 2022/040609, entitled “X-Ray Detection Structure and System”; and in PCT Pat. App. No. PCT/US/2022/081897, entitled “X-Ray Detection Structure with Periodic Scintillator Volumes”; both of which are hereby incorporated herein by reference in their entireties.
In some embodiments, a small configurable detector panel can be conveniently slipped into the small spaces behind hard-to-access objects to allow transmission images to be acquired, even though the field of view may be limited. As examples, embodiments may be used for x-ray scanning of targets such as transmission shafts or truck wheels, where there may not be enough space to move a detector attached to the scanner through the available space.
In some embodiments, the detector panel can be designed to be dual-mode—that is, it can be optimized to detect both transmitted x-rays for transmission imaging, to detect scattered x-rays to enhance the backscatter images, or to acquire side-scatter or forward-scatter images.
In some embodiments, configurable detector panel allows the imaging system to acquire transmission images by placing the detector panel behind the object being imaged relative to the imaging system. Alternatively, in some embodiments, the detector panel can be positioned on the same side of the target as the x-ray imaging system to enhance the backscatter image being acquired with the backscatter detectors built into the imaging system. A further use is to place the detector panel to the side of the object being imaging, allowing both side scatter and backscatter signal to contribute to a combined scatter image. Alternatively, the backscatter and side scatter images can be displayed independently to the operator. A further application is to use the detector panel to detect forward scatter, to enhance the detection of metallic items, such as guns and knives.
The configurable detector panel can have dimensions that are optimized to allow it to be placed in hard-to-reach locations behind or within an object being scanned, such as a car or truck. For example, in reference to
In some embodiments, continuing to refer to
The detector panel may have a width between 1 inch and 18 inches, for example, where width is illustrated in
The positioning arm may be removable from the external detector panel, either for convenience of transport, or for flexibility in imaging applications. The detector panel and/or the positioning arm can be stowed on a portion of the x-ray imaging system, such as on the movable x-ray scanning module or in a case in which the movable x-ray scanning module is stowed for transport.
As described in connection with
In some embodiments, the disclosed configurable detector panels can allow the same x-ray imaging system to be used in at least five possible imaging modes, with rapid interchangeability:
The detector panel may have a width between 1 inch and 18 inches, for example, where width is illustrated in
The positioning arm may be removable from the external detector panel, either for convenience of transport, or for flexibility in imaging applications. The detector panel and/or the positioning arm can be stowed on a portion of the x-ray imaging system, such as on the movable x-ray scanning module or in a case in which the movable x-ray scanning module is stowed for transport.
As described in connection with
In an embodiment, the detector panel can include a low-profile light cavity lined with scintillating phosphor screen. The optical readout of the scintillator is achieved with one or more photodetectors, such as PMTs. As an example, the scintillator screen can include a BaFCl screen, read out with four 1″ diameter PMTs, positioned toward the four corners of the assembly. Typical thicknesses of scintillator screen for a 140 kV instrument range from 80 mg/cm2 BaFCl on the front source-facing interior surface of the detector assembly cavity, to 250 mg/cm2 BaFCl on the sides and rear interior surfaces.
In another embodiment, the detector panel itself can be flexible, by using scintillating phosphor that has a flexible substrate. Alternatively, the scintillating phosphor can be mixed into a flexible, optically transparent matrix material, for example. Since the WSF layers are flexible, the entire detector panel can then be designed to be flexible with the right choice of light-proofing and outer housing material. In some embodiments, the housing material can be a flexible plastic, but a person of ordinary skill in the art can recognize that other flexible materials can be used. In some embodiments, the housing provides a light-proof cavity. In some embodiments, the light-proof cavity prevents all light from entering the cavity. In some embodiments, the light-proof cavity prevents a percentage of light from entering the cavity. In some embodiments, within the housing material is the scintillating phosphor, such that both the housing and the scintillating phosphor are flexible.
A further embodiment provides dual-energy capability for the detector panel. This can use an approach described in U.S. Pat. No. 9,285,488 to Arodzero et al., in which two sheets of scintillator are each read out separately by two respective layers of WSF, and the ratio of the magnitude of the two signals is used to characterize the energy spectrum of the incident beam at any given instant. The above referenced patent is hereby incorporated by reference in its entirety.
Alternatively, the approach described in PCT Pat. App. Pub. No. WO 2022/040609, entitled “X-Ray Detection Structure and System” can be used, in which only one sheet of scintillating phosphor is used, but the signals from two separate layers of WSF on the entrance and exit side of the sheet are used to characterize the energy spectrum of the incident beam.
Analog signals from the one or more PMTs are summed together and then sent to the imaging instrument via a coaxial cable and connector. Alternatively, the signals can be digitized via circuitry installed within the detector panel, and the digitized signals can then be wirelessly transmitted to the imaging instrument, or wirelessly sent to some other remote display device, such as a tablet or a laptop computer. In further embodiments, the output signals can be transmitted both wirelessly and via electrical cables.
When used to detect scatter, the output signals from the detector panel can be combined electrically or in software with the output signals from the built-in backscatter detectors in the instrument before being displayed. Alternatively, the signals can be processed and/or displayed separately. This can be helpful, for example, when looking at objects positioned at a larger distance behind a thick, highly scattering barrier. Scatter from the concealing barrier will preferentially be detected in the built-in backscatter detectors because the active areas of those detectors are closer to the scatter point where the primary beam is incident on the barrier. Depending on where it is positioned, the detector panel may be less sensitive to scatter from the barrier as its active area is farther away from the scatter point on the barrier, and therefore the signal to noise ratio of the concealed object in the backscatter image can be significantly improved if the signal from the detector panel is displayed separately.
The detector panel 1512 can be stationary during a scan, or can be moved by an operator during a scan. The detector panel 1512 can be configured to be connected to the imaging system via an electrical or other optional detector signal cable 1510, as illustrated in
As further described hereinabove, the x-rays received at the external detector module may be x-rays that are transmitted through the target may be x-rays from the sweeping beam that are transmitted through the target. In this manner, an x-ray image formed from the x-ray imaging signal may be a transmission x-ray image. On the other hand, the detector panel, with the aid of the positioning arm, may be placed in a position to receive x-rays that are scattered from the target, such as by forward scattering, back scattering, or side scattering as a result of x-rays from the sweeping beam being incident at the target. Correspondingly, images formed from such x-ray imaging signals may be forward scatter, backscatter, or side scatter images, for example.
Furthermore, the detector panel 1602 can be part of an x-ray detector/imaging system 1601 for detecting a scanning beam of x-rays 1612, where the detector system 1601 includes one or more scintillator volumes configured to be oriented along a scanner axis of a scanning beam of x-rays to receive x-rays from the scanning beam transmitted through a target, the one or more scintillator volumes further configured to produce scintillation photons responsive to receiving the x-rays. A plurality of ribbons of wavelength shifting fibers (WSFs) optically coupled to the one or more scintillator volumes along the scanner axis via a spatial periodic adjacency of the plurality of ribbons to the scan axis can also be provided. The plurality of ribbons can be configured to receive scintillation photons from the one or more scintillator volumes via the spatial periodic adjacency as the scanning beam of x-rays scans over the scan axis. Such a detector system 1601, incorporating the detector panel 1602, can include at least one respective photodetector coupled to an end of each respective ribbon of the plurality of ribbons, each respective photodetector configured to detect the scintillation photons carried by the respective ribbon and to produce a respective signal responsively. The detector system 1601 can also include a signal combiner that combines, selectively, respective signals from one or more ribbons of the plurality of ribbons, for positions of the scanning beam along the scanner axis, to create a combined signal representing a scan of the target with enhanced spatial resolution.
The system of
In another variation, the system of
In another variation of
In another variation of
The teachings of all patents, published applications and references cited herein are incorporated by reference in their entirety.
While example embodiments have been particularly shown and described, 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 embodiments encompassed by the appended claims.
This application claims the benefit of U.S. Provisional Application No. 63/364,190, filed on May 4, 2022 and U.S. Provisional Application No. 63/362,306, filed on Mar. 31, 2022. The entire teachings of the above application(s) are incorporated herein by reference.
Number | Date | Country | |
---|---|---|---|
63362306 | Mar 2022 | US | |
63364190 | May 2022 | US |