Analogic Corporation

Other

Siemens Aktiengesellschaft

Gordon Engineering Company

Bernard M Gordon

Hans J Weedon

John M Dobbs

Leopold Neumann

Douglas Q Abraham

Louis R Poulo

Iosif Izrailit

Lai Ching-Ming

Colin Gyles

Mark H Miller

Eric M Bailey

Carl R Crawford

Timothy R Fox

Enrico Dolazza

Ruvin Deych

Daniel Abenaim

John Fitzallen Moore

David A Schafer

Christopher C Ruth

David Winston

David Banks

Arthur W Crooke

Edwin E Stebbins

Oscar Khutoryansky

Evan Colton

Paul Wagoner

Iosef Izrailit

Richard B Johnson

Hugo G Hernandez

John McG Dobbs

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.

CT scanner for and method of imaging a preselected portion of the lower abdomen region of a patient

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.

Dynamic exposure control in radiography

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. The preferred converter also includes a unique digital filter transfer function, with finite impulse response (FIR) filter characteristics, optimized for CT-DAS applications and having excellent characteristics in the frequency domain and the time domain.

Data acquisition system using delta-sigma analog-to-digital signal converters

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 &ldquo;air scans&rdquo; with objects such as the system conveyor in the field of view. Data gathered during the calibration scan are applied to a threshold, and data exceeding the threshold are assumed to be from X-rays that are unobstructed by objects in the field of view and are therefore used to perform the air calibration. The baggage scanner can also analyze scan data to identify shapes of objects, particularly, objects formed in the shape of a sheet. This greatly improves the ability of the system to detect sheet explosives. The system also compensates for detector dark currents and provides dark current offsets which can be dependent upon detector temperature.

Computed tomography scanning apparatus and method using adaptive reconstruction window

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. The detector arrangement is preferably a 2D array having rows of two or more lengths so that beams of various thicknesses each can be projected onto a row or rows of detector elements having a detection area substantially matched to the corresponding beam. The spatial encoding using the sequence code preferably also allows for one or more sets of multiple slices of equal thickness to be simultaneously generated. By spatially encoding the array with the sequence code, the number of detector elements can be reduced from an array made of detector elements of equal length, i.e., the number of detector elements of each column representing the code is less than N, and more efficient X-ray conversion achieved.

CT scanner comprising a spatially encoded detector array arrangement and method

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.

Digital filmless X-ray projection imaging system and method

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.

Computed tomography scanner with reduced power x-ray source

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.

Self calibrating ring suppression filter for use in computed tomography

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. An improved method of scanning baggage is provided by using the one set of detectors to generate CT image information and the other set of detectors to generate at least one sinogram.

Quadrature transverse CT detection system

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.

Method of and apparatus for power management and distribution in a

A multiple angle tomographic system includes a rotating gantry with a source, e.g., an x-ray source, and detector array combination mounted thereon so as to acquire a plurality of projections of objects passing through the gantry. A pre-screen subsystem utilizes a subset of the projections from those that can be acquired during a full scan so as to define a first plurality of projections--e.g., eight projections--that are sufficient analyze whether there is a likelihood that a targeted object, e.g., a firearm and/or plastic explosives is present. If there is a likelihood that a targeted object is present, a full-image CT reconstruction is commanded, automatically or manually, so as to verify and more fully assess the detected object. This combination of pre-screen and selective full-image CT reconstruction provides thorough inspection of closed containers, e.g., passenger luggage, by providing multiple angle and perspective viewing of targeted objects.

Multiple angle pre-screening tomographic systems and methods

A scanning tomography system has a gantry including a disk for supporting a X-ray source and detector array and rotatable about a central axis. Multiple scans are made to reduce the effects of motion artifacts and improve image quality. In addition, the detector array is supported by a suspension system and is movable about the focal spot of the X-ray source a small amount so that in one mode of operation the detector array can be shifted at a predetermined angle from one position to at least one other position during a scan so as to provide an increase in the number of unique X-ray paths so as to provide improved image quality. In a second mode of operation, the detector array can be offset from the center ray so as to provide a quarter of a detector offset.

X-ray tomography system for and method of improving the quality of a

Ring suppression filter for use in computed tomography systems

The disclosed dual energy baggage scanning assembly includes a CT scanning system, and a conveyor belt for transporting items through the CT scanning system, and an improved power supply for the X-ray source of the CT scanner so that a dual energy beam is provided. The power supply alternately powers the X-ray tube of the scanning system at high and low voltage levels at a predetermined rate and comprises at least one high voltage DC power supply for providing a stable, high DC voltage the X-ray tube; means, including at least one waveform generator, for providing a periodic time varying waveform; and coupling means, including a transformer, for coupling the waveform generator to said DC voltage supply so that the total voltage across the cathode and anode of the tube is periodically changed between the high and low voltage levels at the predetermined rate in response to the periodic time varying waveform provided by the waveform generator.

Growing community of inventors

Manchester-by-the-Sea, MA, United States of America

Bernard M Gordon