Abstract: A radiation phantom comprising a solid opaque housing having an inner chamber is provided within which a test pattern for quantifying image quality, and at least one dosimeter for simultaneously measuring radiation dosage are randomly disposed. A tamper proof means is connected to the opaque housing such that the test pattern and the at least one dosimeter are unviewable and unaccessible within the chamber. Thus, the test pattern and the at least one dosimeter are "interlocked" within the radiation phantom housing such that the radiation phantom can be employed to accurately evaluate off-site a radiation machine's imaging of the radiation phantom without requiring the presence of an independent qualified technician on-site during irradiation of the phantom.

Abstract: A phantom for determining attenuation by a combination of materials of polychromatic X-rays comprises a number of tubes that can be positioned in between a source emitting said X-rays and an X-ray detector. The tubes are held in a position so that they are directed towards the position of a source of radiation. In each tube a combination of thicknesses of said materials is provided.

Abstract: An x-ray phantom provides at least two vertebral models one of which represents a case of clinically recognized deformity relevant to the evaluation of osteoporosis. The two vertebral models are mounted with respect to each other to simulate a second spine and to permit changing of the attitude and relative orientation of the vertebral models with respect to each other. The mounting may provide variable degrees of spine curvature and permit substitution of different vertebral models simulating different deformities. The vertebral models have known bone mineral densities to permit the evaluation of automatist bone density/morphometry techniques.

Abstract: An x-ray CT scanner is operated in a test mode to acquire attenuation projections using a phantom shaped to accentuate errors due to non-uniform detector response along the z-axis. Error values are calculated for detector elements and these error values are compared with preset limits to identify faulty or marginal detector elements.

Abstract: A phantom constituted by a helix is used. This helix enables an automatic geometrical calibration of any X-ray imaging system that uses a plane detector.

Abstract: A calibration for standardizing images taken with X-ray radiation includes an elongated parallelepiped box of dimensions of at least about 14" (35.56 cm) by 17" (43.

Abstract: A calibration phantom representative of human tissue containing variable concentrations of calcium serves as a calibration reference for quantifying calcium, bone mass and bone mineral density in radiography and CT imaging systems. The method of fabrication of the calibration phantom provides the long-term stable incorporation of calcium into a tissue equivalent material which allows accurate, standardized, and reproducible quantification of calcium and bone mineral density in radiography and CT imaging systems. A method of using the calibration phantom for quantifying calcium and bone includes placement of part of a patient's anatomy in a bolusing apparatus to provide uniform attenuation of the x-ray beam passing through and around the patient's anatomy. A x-ray filter plate may be used to predictably attenuate the x-ray beam.

Abstract: A transmission phantom for total performance assessment of scintillation camera imaging has a constant thickness and at least two layers of homogenous material each layer having different radiation attenuating properties. A layer having a moderate attenuation provides relief areas and a radiation absorbing layer conforming to the relief areas provides for variable transmission through the phantom corresponding to the thickness of the absorbing layer to simulate pathological conditions in a patient. The method of manufacture includes the preparation of a relief mold including a bottom plate and side walls. The radiation absorbing material is poured into the mold, allowed to hardened and milled to a flat surface.

Abstract: A phantom for simulating a patient during an X-ray exam that involves introducing a high contrast material into the patient. The phantom comprises a base and a first contrast element. The first contrast element is disposed within the base and has an X-ray attenuation greater than that of the base. The contrast ratio of the first contrast element to the base is approximately 50. In one embodiment of the phantom, the first contrast element contains iodine. In another embodiment, the base has a shape which occupies the entire field of view of the X-ray exam and the first contrast element is positioned substantially in the center of the field of view. In yet another embodiment of the phantom, a second contrast element is disposed within the base and has a contrast ratio to the base of approximately 1.5.

Abstract: A phantom for use in calibrating dual energy X-ray absorptiometry and quantitative computed-tomography includes one or more sections which are equivalent to bone to X-rays and which have a shape resembling a lumbar vertebra. Each section includes a substantially cylindrical main body simulating the vertebra centrum, a band simulating the neural arch, and transverse and posterior processes extending from the band. The transverse processes are formed in a define wedge shape which tapers down from its attachment to the neural arch band. The section, or stacked sections, are embedded in a matrix of plastic material equivalent to water or tissue.

Abstract: The disclosure concerns X-ray scanners and, more particularly, a method to measure the bone density of a patient that takes his or her build into account. The disclosed method consists in performing a calibration of the bone density measurement by means of a phantom that simulates the patient's body and the vertebra an calibration phantom comprising a water insert and an insert with a high concentration of K.sub.2 HPO.sub.4. A measurement is made of the densities of several inserts of different concentrations and of the concentration of the water insert and of the K.sub.2 HPO.sub.4 high concentration insert, in the presence and without the presence of the bag of water, enabling the computation of corrections of the measured density of the patient's vertebra depending on his or her build.

Abstract: A method and system to calibrate an X-ray scanner uses a single circular phantom. The circular phantom is off-centered with respect to the axis of rotation of the scanner so as to introduce different paths in the phantom for each channel, depending on the angular positions of the scanner. This results in different attenuation measurements which are compared with values obtained by the computation of the path lengths which depend on the off-centered coordinates r and .PHI. and on the position of the scanner, thus enabling computation of the polynomial approximation coefficients to be applied to the measurements.

Abstract: A set of interchangeable pieces comprising a computerized tomography calibrator, and a method of use thereof, permits focusing of a computerized tomographic (CT) system. The interchangeable pieces include a plurality of nestable, generally planar mother rings, adapted for the receipt of planar inserts of predetermined sizes, and of predetermined material densities. The inserts further define openings therein for receipt of plural sub-inserts. All pieces are of known sizes and densities, permitting the assembling of different configurations of materials of known sizes and combinations of densities, for calibration (i.e., focusing) of a computerized tomographic system through variation of operating variables thereof. Rather than serving as a phanton, which is intended to be representative of a particular workpiece to be tested, the set of interchangeable pieces permits simple and easy standardized calibration of a CT system.

Abstract: In a tomographic image diagnostic apparatus, a region of interest is automatically set on a tomographic image by recognizing actual positions of a phantom based upon CT (computerized tomographic) values of the phantom. The phantom is made of a base portion having a first reference CT value and a plurality of rods each having a second reference CT value. The region of interest is defined by recognizing the gravity centers of these rods.

Abstract: A calibration phantom for the quantitative computer tomography (QCT) system for bone or other tissue measurement in which a series of graduated reference solutions are retained within cavities formed in a translucent member having x-ray attenuation characteristics closely approximate to human tissue. In preferred embodiment, the reference solutions are sealed under pressure in direct contact with the material forming the base of the phantom. Only a very thin wall separates the solution from the upper and lower surfaces of the phantom. In addition, the cavities are closely adjacent one another. As a result, phantoms constructed in accordance with this invention minimize the size and mass of the phantom and thus minimize x-ray beam hardening, scatter and image are the facts.

Abstract: A polymer attenuation filter in a CT machine is mounted at its center and allowed to expand freely at its ends to prevent cracking of the filter as it expands with temperature and after it becomes brittle with x-ray exposure. Vertical expansion of the filter at its center is accommodated by a stress relief hole cut between the center fastening points. Relatively greater horizontal expansion is accommodated by means of spring clamping. Difference in expansion between a metallic strip filter and its support is accommodated by tightly affixing the ends of the filter to the support so that the metallic strip is always under tension and cannot buckle.

Abstract: The present invention concerns a method of calibrating a tomographic system which is used for testing earthen cores. At least two phantoms of a first type of phantom is used in calibrating for contrast resolution. At least two phantoms of a second type of phantom are used to calibrate the tomographic system for beam hardening.

Abstract: An automated image detail localization system for digital image systems, such as CT, MRI, digital radiograph, includes a calibration phantom having plural reference samples of materials having known, fixed imaging properties. The phantom is positioned with respect to a patient and scanned simultaneously to produce an image that includes a cross-section of the patient and a cross-section of the phantom. The cross-sectional image of the phantom includes cross-sectional images of the reference samples. The system automatically finds the phantom and the centers of the reference sample images and then positions regions of interest (ROIs) within the reference sample images to define the portions of the images that are included in a step of averaging the intensities of the reference sample images. The system further automatically places an ROI of regular (e.g., elliptical) or irregular shape in a specific region of the image of the patient's anatomy, such as the trabecular bone region of the patient's spine.

Abstract: A computed tomography system which includes both a high-energy imaging apparatus (such as an X-ray computed tomography device) and also one or more phantoms whose solid characteristics generally correspond to the density and shape (preferably including external and internal contours) of the existing object to be imaged. The phantom is used for differential error-correction techniques, which permit very accurate imagining of the contours of bones in vivo. The accurate images thus derived permit fabrication of orthopedic prostheses which have an extremely accurate fit to existing bone structure.

Abstract: A fan beam of radiation (12) is projected on first and second detector arrays (18, 20). The detector arrays and fan beam are swept across a phantom (D). Fine wires (82) in the phantom each cast shadows over fractions of a plurality of the detectors during the sweep. Phantom images (44, 46) are generated from the first and second detector arrays with corresponding pixels of each image corresponding to the same path between a radiation source (10) and corresponding detectors in the arrays. A linear interpolation (50) interpolates the pixels of one of the images to shift their effective spatial position. A transform means (52) transforms the linear interpolated and second phantom image into at least one composite image (54). The linear interpolation is iteratively adjusted (C) to minimize phase change artifacts in corresponding pixels of the composite image. After the appropriate interpolation for each detector or group of detectors has been determined, the appropriate linear interpolations are stored (72).

Abstract: A reference phantom system for quantitative computer tomography employs a flexible reference phantom with means for urging the flexible reference phantom into contact along the curved surface of the lumbar region of a human patient. In one embodiment, the reference phantom is pre-curved in an arc greater than required. Pressure from the weight of a patient laying upon the reference phantom is effective for straightening out the curvature sufficiently to achieve substantial contact along the lumbar region. The curvature of the reference phantom may be additionally distorted by a resilient pad between the resilient phantom and a table for urging it into contact with the lumbar region. In a second embodiment of the invention, a flexible reference phantom is disposed in a slot in the top of a resilient cushion.

Abstract: A system and method is disclosed for utilizing image pixel value information generated by a digital radiographic system for quantifying the amount of calcium in a particular object of interest within a subject, wherein the subject also contains additional quantities of calcium located at positions such that the additional calcium interfers with the acquisition of data describing the object of interest. A cursor configured as a parallelogram is described and pixel values are summed along lines parallel to the sides of the parallelogram. A profile is generated from these summations. A portion of the profile corresponding to pixel lines not intersecting the object of interest is used to estimate the contribution of background and other calcium to the profile as a whole, and this estimated value is subtracted from the total profile. Integration of the remainder of the profile provides a scalar value corresponding to the amount of calcium in the object of interest.

Abstract: This specification sets forth a cardiovascular phantom. The phantom is adapted for placement on a table between an X-Ray tube and a film camera. The phantom is formed from absorptive material comprising at least one layer of metallic material on a plastic board. The metallic material is formed in the shape of arterial vessels from a radiopaque material. The radiopaque material and phantom absorb the X-Rays in an analogous manner to a person's heart. The phantom provides an analog to allow adjustments for the X-Ray process used for cardiovascular analysis.

Abstract: The present invention relates to a gauge for use with x-ray machines to calibrate correct technic values (exposure, kilovoltage, processing conditions, etc.) for x-ray film to yield anatomically correct film densities over the visible density range. The gauge accomplishes this by including only four sections. In particular, a first portion for achieving correct film densities at the low end of the visible density range and a second portion for achieving correct film densities at the high end of the visible density range. The gauge also includes at least one region for achieving a slight variation in film density in each of the first and second above-named portions. The gauge may be encased by being cast in plastic of a particular thickness and absorption of x-rays. With this gauge, the radiographer examines film densities at the upper and lower limits of the visible density range to distinguish overexposure, upper limits of correct exposure, correct exposure, lower limit of correct exposure and underexposure.

Abstract: X-ray energy in an x-ray beam is determined from a comparison of apparent absorption of energy by three different materials. Initially, the attenuation coefficients of each of the materials as a function of x-ray energy is determined. The ratios of attenuation coefficient differences between two of the materials and between one of the two materials and the third material are plotted over an energy range of interest. Thereafter, the materials are x-rayed and their absorption characteristics determined. The ratio between the differences in absorption characteristics is then calculated in the same manner as the ratio of attenuation coefficients. Matching ratios are then used to identify the energy level of the x-ray beam.

Abstract: A hand-held inertial mouse provides input data to a computer from which the computer can determine the translational and angular displacement of the mouse. The mouse includes accelerometers for producing output signals of magnitudes proportional to the translational acceleration of the mouse in three non-parallel directions. Pairs of these accelerometers are positioned to detect acceleration along each axis of a cartesian coordinate system such that an angular acceleration of the mouse about any axis of rotation causes representative differences in the magnitudes of the output signals of one or more of these accelerometer pairs. The translational velocity and displacement of the mouse is determined by integrating the accelerometer output signals and the angular velocity and displacement of the mouse is determined by integrating the difference between the output signals of the accelerometer pairs.

Abstract: In a computer tomography system, a flexible calibration phantom is utilized simultaneously with analysis of a patient to ensure accuracy of imagry and to facilitate interpretation of tomographs created. The flexible calibration phantom is preferably placed directly upon a patient between a radiation source and a radiation detector. It includes two solid and flexible samples of reference materials, each having a substantially uniform density, and a solid and flexible encasement surrounding the samples of reference material. The encasement has a substantially uniform density different than that of each of the samples of reference material, and the combination provides suitable reference points for proper analysis of tomographs obtained.

Abstract: A xenon concentration phantom (A) is mounted in a CT scanner (B). A xenon/oxygen breathing gas mixture from a breathing gas supply system is (C) circulated through an analysis chamber (12) of the phantom before a human scan is commenced. The CT scanner measures the amount of radiation absorption attributable to the gas in the analysis chamber, which absorption varies in proportion to the concentration of xenon gas. The measured radiation absorption is converted into a precise measurement or indication of the xenon concentration of the breathing gas. The precise xenon concentration measurement may be utilized to calibrate xenon gas detectors (80, 100) in the breathing gas supply system or to calibrate xenon concentration dependent diagnostic data generated during a subsequent patient scan while the patient is breathing the breathing gas.

Abstract: A phantom (FIG. 1) has a bone mineral standard (B) surrounded by tissue equivalent material (A) with a plurality of different cross sections. The phantom is disposed in an image region (44) of a tomographic scanner (FIG. 2). Scans are conducted through a plurality of different cross sections of the phantom to reconstruct a plurality of phantom image representations (62). The plurality of phantom image representations are stored by size in a correction memory (70). Thereafter, a patient is disposed on a patient table (50) in the image region and an image is taken through the patient's mid-section between the L2 and L5 vertebrae. A patient image representation is reconstructed and stored in an image memory (64). A slice size calculation circuit (72) determines the size of the patient slice. The correction memory is addressed with the calculated size to retrieve the phantom image representation of the most similar size.

Abstract: A phantom formed of a non-biological material into the shape of a breast, said material having radiation characteristics of breast tissue, for use by medical personnel while in training to interpret mammographs, and as a tool to assess the quality of a radiological imaging system. The phantom material comprises one epoxy resin based tissue substitute which simulates the breast tissue, and another which simulates the skin tissue. A slot is formed in the phantom into which targets for simulating breast masses, fibers and calcifications can be placed.

Abstract: A test phantom and method of fabrication and use of the same is disclosed which phantom is representative of human tissue containing variable concentrations of iodine to serve as a test device in for assessing the performance of X-ray imaging systems such as digital subtraction angiographic apparatus. The method of fabrication provides the long-term stable incorporation of iodine into a tissue equivalent material which allows standardized testing and evaluation of X-ray imaging systems. The incorporation of additional test details into geometrically fixed positions in the phantom allows accurate and reproduceable measurements of other performance parameters of digital X-ray imaging systems.

Abstract: Disclosed is a test phantom for evaluating a computed tomographic scan of nodules in a lung of a human or non-human animal comprising a device which simulates a 15 to 40 mm thick transverse section of said animal the tissue simulating portions of said device are constructed of materials having radiographic densities substantially identical to those of the corresponding tissue in said simulated transverse section of said animal and contain voids therein which simulate, in size and shape, the lung cavities in said transverse section. At least one of the voids has positioned therein a test reference device constructed of a material of predetermined radiographic density which simulates a lung nodule.

Abstract: Disclosed are x-ray machines using fan-beams of x-rays to examine sectional slices of patients and to form detailed x-ray pictures of such slices, and methods of so examining patient slices. A source of a fan-beam of x-radiation, and a system detecting the radiation after it passes through a slice of the patient, rotate around the patient.

Abstract: A method of testing a ceramic article, comprising photographing a ceramic article by X-ray computed tomography in a state where at least one portion of the ceramic article is placed in a filling material having an X-ray absorption coefficient close to or less than that of the ceramic article in order to simplify the shape of a combination of the ceramic article and the filling material, thereby allowing precise and easy detection of microdefects in a ceramic article which has a complex shape.

Abstract: Apparatus for investigating a part of a body intermediate the extremities thereof by means of X- or .gamma.-radiation is disclosed. The body part is surrounded by a liquid medium; the liquid medium being retained in an enclosure having a tubular inner wall formed of flexible material, and the body part is located within the inner wall. The liquid medium can be pressurized to cause the flexible inner wall to fit intimately the periphery of the body part.

Abstract: A reference detector device for a multidetector tomodensitometer comprises several reference detectors. It also comprises filters reproducing the most current objects as regards X-ray attenuation. Each reference detector is associated with one of the filters. A reference value, at a given instant, is obtained by a combination of the values detected at the same instant on different reference detectors.

Abstract: In the X-ray CT system, the X-ray detectors vary in output characteristics such as linearity, directivity and radiation quality from one detector to another. To make compensations for such irregularities, a plurality of phantoms of different absorption is prepared in the CT system according to the present invention. Namely, this plurality of phantoms is set one by one in the measuring space in the same manner as in the examination of an examinee or subject to be examined; the coefficient of X-ray absorption is determined for each of these phantoms. Further, theoretical values of absorption for each phantom are compared to the actual absorption measurements on each phantom to provide an absorption error value for each detector at differing absorption levels. The actual subject absorption value for each detector is used to pick the two error values closest to the actual value. The two error values are interpolated or extrapolated to find an error value for correcting the actual absorption value.