Abstract: A scanning system includes an improved arrangement of shielding curtains to limit radiation leakage while achieving high throughput and limiting system length. The scanning system includes a segmented conveyor, including a faster conveyor through a shielding region to improve increase throughput of scanned articles, and a slower conveyor through a scanning region to ensure acceptable scanning performance. The curtains are arranged based on the changing gap distance between the articles that results from the changing conveyor speeds.

Abstract: A method for scanning an object in an X-ray security inspection system, wherein the X-ray security inspection system comprises an ingoing tunnel equipped with radiation-shielding curtains, an X-ray section and an outgoing tunnel equipped with radiation-shielding curtains, the method comprising: passing the object through the ingoing tunnel at a first rate of speed and with a first extent of separation between successive objects; passing the object through the X-ray section at a second rate of speed and with a second extent of separation between successive objects; and passing the object through the outgoing tunnel at a third rate of speed and with a third extent of separation between successive objects; wherein the second rate of speed is less than the first rate of speed and the third rate of speed, and wherein the second extent of separation between successive objects is less than the first extent of separation between successive objects and the third extent of separation between successive objects.

Abstract: An improved dual energy CT imaging system for providing improved imaging and improved material identification.

Abstract: An improved dual energy CT imaging system for providing improved imaging and improved material identification.

Abstract: A method for scanning an object in an X-ray security inspection system, wherein the X-ray security inspection system comprises an ingoing tunnel equipped with radiation-shielding curtains, an X-ray section and an outgoing tunnel equipped with radiation-shielding curtains, the method comprising: passing the object through the ingoing tunnel at a first rate of speed and with a first extent of separation between successive objects; passing the object through the X-ray section at a second rate of speed and with a second extent of separation between successive objects; and passing the object through the outgoing tunnel at a third rate of speed and with a third extent of separation between successive objects; wherein the second rate of speed is less than the first rate of speed and the third rate of speed, and wherein the second extent of separation between successive objects is less than the first extent of separation between successive objects and the third extent of separation between successive objects.

Abstract: An improved dual energy CT imaging system for providing improved imaging and improved material identification.

Abstract: A CT scanner and method are designed to scan a preselected portion of a patient's lower abdomen. The scanner may include a source and detector array designed to rotate about a rotation axis oriented substantially parallel to or coincident with the hips of the a patient so that a scanning plane does not pass through the patient's pelvic bones Higher-resolution image CT images can be achieved by using a detector array of the type used for digital radiography. The presence of prostatic cancer can be detected by first injecting the patient with a material including a high contrast material for X-ray imaging and a material for binding the high contrast material to a specific biological site if present in the preselected portion of the lower abdomen of the patient; and generating a CT image of the preselected portion of the lower abdomen.

Abstract: A method and system is presented in radiography for optimizing image quality of an object (e.g. an anatomical region of a patient), while minimizing the radiation dose to the patient. X-ray exposure parameters, such as operating voltage (kVp), operating current (mA), focal spot size, and soft x-ray filter combination, are dynamically controlled during the x-ray exposure. During at least two different sampling intervals and at two different kVp levels, x-rays are passed through the object, and detected by sensors located between the object and the image plane. After the last sampling interval, the sensor output signals and the measured thickness of the object are used to evaluate the optimal settings for the x-ray exposure parameters. The x-ray exposure parameters are set to these optimal settings for the remainder of the exposure period.

Abstract: A delta-sigma A/D converter includes a delta-sigma modulator having an integrating amplifier dispose within the loop of the modulator so that the input of the modulator can be connected to receive relatively low level input currents, and so as to improve DC stability. The modulator is specifically adapted for IC implementation for use in a DAS of a CT scanner so that the current output of a detector of the scanner can be connected directly to the input of the modulator of the converter. The noise shaping characteristics are shaped so as to provide an improved frequency response with minimal spillover. Noise shaping of the converter is provided throughout the dynamic range of the current outputs of CT scanner detectors so as to compensate for the poorer S/N for low input currents.

Abstract: A CT scanner 10 and method are designed to scan a preselected portion of the lower abdomen with higher resolution and lower power. The scanner is constructed with a source 14 and detector array 16 designed to rotate about a rotation axis oriented substantially parallel to or coincident with the hips of the a patient so that X-rays do not have to pass through the pelvic bones to image the area of interest. Higher resolution can be achieved by using a detector array of the type used for digital radiography so that individual detectors can be much smaller than those used in conventional CT machines.

Abstract: A delta-sigma A/D converter includes a delta-sigma modulator having an integrating amplifier dispose within the loop of the modulator so that the input of the modulator can be connected to receive relatively low level input currents, and so as to improve DC stability. The modulator is specifically adapted for IC implementation for use in a DAS of a CT scanner so that the current output of a detector of the scanner can be connected directly to the input of the modulator of the converter. The noise shaping characteristics are shaped so as to provide an improved frequency response with minimal spillover. Noise shaping of the converter is provided throughout the dynamic range of the current outputs of CT scanner detectors so as to compensate for the poorer S/N for low input currents.

Abstract: A method and apparatus for performing CT scans of baggage being carried or loaded onto commercial aircraft are described. The CT baggage scanner of the invention includes numerous features which provide the system with high baggage throughput on the order of seven hundred bags per hour as well as improved image quality and accurate target detection. In one aspect, the scanner includes an adaptive image reconstruction window which identifies data collected from the field of view that are not related to the baggage being scanned. These unrelated data are excluded from the image reconstruction process, resulting in greatly reduced reconstruction time and increased baggage throughput. The invention also includes the capability of performing calibration “air scans” with objects such as the system conveyor in the field of view.

Abstract: A delta-sigma A/D converter includes a delta-sigma modulator having an integrating amplifier dispose within the loop of the modulator so that the input of the modulator can be connected to receive relatively low level input currents, and so as to improve DC stability. The modulator is specifically adapted for IC implementation for use in a DAS of a CT scanner so that the current output of a detector of the scanner can be connected directly to the input of the modulator of the converter. The noise shaping characteristics are shaped so as to provide an improved frequency response with minimal spillover. Noise shaping of the converter is provided throughout the dynamic range of the current outputs of CT scanner detectors so as to compensate for the poorer S/N for low input currents.

Abstract: A CT scanner comprising a spatially encoded detector arrangement for providing data values representing variable thickness slices, and a method of efficiently detecting X-rays for variable thickness slices of a CT scanner are disclosed. The spatially encoded detector arrangement includes a plurality of columns of detector elements, with the detector elements of each column being distributed and arranged so that the lengths of at least some of the detector elements of each of the columns vary in accordance with a predetermined sequence code that represents all of the whole integer values in equal increments from 1 to N, wherein N is a whole integer greater than 1, and preferably greater than 3. Preferably, the sequence code is a biquinary code of 5, 2, 2, 1 so that N is at least 10.

Abstract: A system for and method of producing digital filmless X-ray projection images having resolution and dynamic range characteristics comparable to extant photographic film-based images includes an X-ray source directing an X-ray beam through an object to be viewed toward a detector array, a drive mechanism for rotating the detector array in a plane substantially normal to the X-ray beam, and a reconstruction computer for generating an image from projection data taken from the detector array. The system generates a projection data set corresponding to each of a plurality of incremental angular positions of the detector array, and the reconstruction computer combines the data sets to form a two dimensional projection image of the object being viewed.

Abstract: The disclosed CT scanner includes an X-ray source and an array of X-ray detectors fixed to a reduced geometry disk which is supported for rotation about an isocenter of the disk. The X-ray source is a reduced power source and a beam hardening filter of reduced size is positioned proximal to the X-ray source so the scanner uses a relatively soft X-ray beam. The scanner further includes circuitry for compensating for non-linearities and channel-to-channel variation in the X-ray detectors.

Abstract: A computed tomography (CT) system utilizes a ring suppression filter for suppressing ring artifacts in a CT image. The system generates projections at a plurality of projection angles, and each projection includes one measurement of a plurality of projection data signals. The ring suppression filter includes a high pass filter, a histogram generator, and a combiner. The high pass filter generates a measurement of an error signal corresponding to each of the measurements of one of the projection data signals, and each of the error signal measurements is representative of the high frequency components in a portion of one of the projections. The histogram generator generates a histogram signal representative of a relationship between the measurements of the error signal and the measurements of the projection data signal. The combiner combines the measurements of the error signal and the histogram signal to generate a plurality of measurements of a ring corrected signal.

Abstract: The disclosed detector system includes a two dimensional array of detectors for use in generating a volumetric scan of objects moving through a scanner. The array can comprise rows and columns of square detectors, or alternatively at least two types of detectors, one for providing high image resolution in a direction parallel to or within a plane containing the X- and Y-axes of a CT scanner, and the other for providing high image resolution e direction of the Z-axis of the scanner. Preferably, a first set of detectors is oriented in one direction and a second set of detectors is oriented in a different direction. The disclosed detector system may be used in connection with CT scanners and, in particular, with CT baggage scanners and is particularly useful for detecting the presence of thin objects such as sheet explosives within scanned baggage.

Abstract: An apparatus for energizing a large scale medical imaging system, preferably in the form of a CT scanner so that the scanner operates off an uninterruptable power supply in the event that the external power falls below sufficient power to operate the system so that system operation remains uninterruptable. The system is designed to operate off a broad range and types of external power supplies including those providing DC, single or three phase AC power. The system therefore can operate from a common single phase AC outlet. In addition, power factor correction is provided so that the system can correct for phase differences between the voltage and current at the input line created by the input impedance of the system.

Abstract: Accordingly, the present invention provides an x-ray tomography apparatus having a patient table, x-ray tomography components located around the patient table and in an imaginary plane which intersects the table, and structure for supporting the table and tomography components and including apparatus for moving the tomography components along at least a portion of the table. In an alternate embodiment, an x-ray tomography apparatus includes an annular x-ray tomography system for continuously rotating around a patient, which structure has an electrically powered x-ray source and battery power for supplying electrical power to the x-ray source.