Abstract: The image of an object is improved by estimating the scattered radiation that it transmits to the detectors. To achieve this, one uses the scattered radiation effectively measured through an imitation of the object, having analogous attenuation properties, and which one modifies by the weighting coefficients obtained by a transformation of the values of the total radiation received through the object (3) and the selected imitation (8). One thus manages to improve the image without subjecting the object to a double irradiation in order to measure the scattered radiation separately. The principal applications are tomography, bone densitometry and non-destructive controls.

Abstract: The present invention provides a method for determining a geometry of a scanning volumetric computed tomographic (CT) system having a rotation axis, a rotational plane, an x-ray source and a detector. The method includes scanning a phantom having a series of spatially separated discrete markers with the scanning volumetric computed tomographic system, wherein the markers are configured on a supporting structure of the phantom so as to permit separate identification of each marker in a collection of projection images. The method further includes locating images of the markers in each projection, using the located marker images to assign marker locations to tracks, and using the assigned tracks, determining a relative alignment between the detector, the source, and the rotation axis of the scanning volumetric computed tomographic system.

Abstract: In an x-ray computed tomography apparatus and a method for conducting test measurements therein, a combined phantom is employed that is formed of several individual phantoms, each forming a segment of the combined phantom, and the combined phantom is affixed to a platform of the computed tomography apparatus that is movable with respect to an x-ray data acquisition unit of the computed tomography apparatus. The platform is moved into a first position and a first x-ray absorption distribution of a first segment of the combined phantom is obtained, and the platform is moved into a second position and a second x-ray absorption distribution is obtained of a second segment of the phantom. Movement of the platform and operation of the data acquisition unit for obtaining the first and second x-ray distributions are automatically controlled by a computer program.

Abstract: Certain embodiments relate to a method and apparatus for calibrating an imaging system having an array of detector elements arranged with respect to a reference position and having an energy source moving in a pattern to irradiate the array of detector elements. The method includes initiating estimated detector positions for the array of detector elements and an estimated motion pattern for the energy source. The estimated detector positions and motion pattern are defined with respect to a reference position in the imaging system. The method further includes scanning a phantom having pins located at positions in the phantom and calculating estimated pin positions, with respect to the reference position, based on at least one of the estimated detector positions and motion pattern. The method further includes modifying at least one of the estimated detector positions and motion pattern based on at least two of the estimated detector positions, motion pattern and pin positions.

Abstract: A method is for calibration of a transformation of at least two X-ray attenuation values (which are determined using different X-ray spectra) for a material, to a value for the density and a value for the atomic number of the material. A first distribution is recorded of first X-ray attenuation values obtained from a calibration phantom using a first X-ray spectrum, and a second distribution is recorded of second X-ray attenuation values obtained from the calibration phantom using a second X-ray spectrum. The recorded X-ray attenuation values are used to produce a density function and to produce an atomic number function. A value for the density and for the atomic number of the calibration sample is determined with the aid of the density function and the atomic number function, and a discrepancy between the determined values and the actual density and atomic number of the calibration sample is found.

Abstract: A computed tomography (CT) image quality phantom for use in calibrating explosive detection systems (EDS) at airports. A foam core block containing up to five right cylinder rod members is positioned in a housing member which is adapted to be passed through an airport luggage scanning machine. The rod members are of different lengths in order to create different data slices for analysis. The housing has a lead-in member at least at one end in order to allow passage through an EDS more easily and provide accurate CT calibrating.

Abstract: A hybrid calibration method uses an calibration phantom (exterior reference) scanned simultaneously with the patient, and one or more known tissues of the subject (interior reference) to create a hybrid calibration reference that improves the measurement of tissue densities throughout the body. In addition, the calibration method is used to quantitatively define boundaries of tissue and organs for more accurate measurements of lengths, areas and volumes. Another aspect of the invention uses the calibrated images to quantitatively preset absolute window/levels for filming and image display, which provides standardized viewing for diagnostic purposes.

Abstract: A method and apparatus for providing an image quality test and reporting method for x-rays that allows a field engineer to effectively maintain and troubleshoot vascular imaging systems produced by all manufactures. In general, the method and apparatus of the present invention provides for a test stand, a plurality of x-ray test phantoms (10, 20, 30, 40, 50, 60, 70) and a computer program for data entry, analysis and storage of the test results.

Abstract: A volume phantom for radiation therapy verification employs film held in a spiral configuration within a equalizing ring of attenuating material. The ring provides improved uniformity in radiation measurement and may be extended, for example, to a hemisphere to provide improved modeling and simulation of treatments in the region of the head.

Abstract: An apparatus and method for establishing a correction characteristic curve for a reduction of artefacts in a tomography are described. Projection data of the object is provided, wherein the projection data comprises transmission values for the object. A representation of the object is calculated from the projection data to obtain two or three-dimensional representation data for the object. A measure for the transmission length of the object is determined by using the representation data. A transmission value, which is associated to the determined measure for the transmission length, is determined and the correction characteristic curve of several determined measures is generated for transmission lengths and associated transmission values, wherein a precorrection of the projection data can be performed by using the determined correction characteristic curve, to iteratively determine the correction characteristic curve by using the precorrected transmission values.

Abstract: A contrast phantom for assessing the characteristic, exposure-related signal and noise response and dynamic range of an image recording and detection system. The contrast phantom is composed of an absorber medium having a sudden K-edge absorption change of the mass attenuation coefficient for at least one photon energy level in-between the mean and maximum energies of the lowest energy spectrum it is subjected to. The invention further provides a method for assessing the characteristic, exposure-related signal and noise response and dynamic range of an image recording and detection system with the aforementioned contrast phantom.

Abstract: Disclosed is a phantom for dose verification for intensity-modulated radiation therapy having a base of substantially tissue-equivalent material and a two-dimensional array of cavities formed in the base with each the cavities being configured and dimensioned to receive a radiation detector.

Abstract: Techniques for deriving bone properties from images generated by a dual-energy x-ray absorptiometry apparatus include receiving first image data having pixels indicating bone mineral density projected at a first angle of a plurality of projection angles. Second image data and third image data are also received. The second image data indicates bone mineral density projected at a different second angle. The third image data indicates bone mineral density projected at a third angle. The third angle is different from the first angle and the second angle. Principal moments of inertia for a bone in the subject are computed based on the first image data, the second image data and the third image data. The techniques allow high-precision, high-resolution dual-energy x-ray attenuation images to be used for computing principal moments of inertia and strength moduli of individual bones, plus risk of injury and changes in risk of injury to a patient.

Abstract: An edge phantom for assessing the sharpness response of a radiation image recording and detection system wherein the edge phantom is subjected to radiation emitted by a source of radiation to generate a radiation image and wherein the radiation image, recorded and detected by the system, is evaluated. The design of the edge phantom provides that any line outside a plane perpendicular to the edge phantom's top face, connecting the focus of the source of radiation with a point on a curved or flat lateral face of the phantom used for sharpness analysis coincides with a line part of that lateral face containing that point.

Abstract: Certain embodiments include a system and method for scatter measurement and correction. The method includes performing a calibration scan using a phantom to measure a scatter signal ratio between scatter x-rays impacting a first detector ring and scatter x-rays impacting a second detector ring. The scatter signal ratio is used to determine a scatter scale factor. The method further includes positioning a collimator such that the first detector ring is occluded from a path of primary x-rays generated by a target. The method also includes executing a low exposure scan to obtain x-ray scatter data using the first detector ring and the second detector ring and applying the scatter scale factor to the scatter data to produce scaled scatter data. The method further includes obtaining image data using the first detector ring and/or the said second detector ring and adjusting the image data using the scaled scatter data.

Abstract: A device is provided for recording in at least two planes radiation from a radiotherapy apparatus. The device comprises a dimensionally stable frame which is adapted to be arranged in a defined position relative to the radiotherapy apparatus, an attachment on the frame for a recording means, and a recording means which extends from the attachment at an acute angle to the frame along an axis of rotation and to the center of the frame. The recording means is adapted to assume at least two defined rotational positions on the axis. In addition, the recording means exhibits a surface for supporting a radiation recording unit, which surface is located in a plane that forms an acute angle with the axis of rotation, the plane of the surface when rotating the recording means being adapted to turn on a single pivot point which is fixed relative to the frame.

Abstract: Method and apparatus for examination of a breast, in which a contrast medium is injected in the breast to be examined, an X-ray beam is emitted in the direction of the breast; a plurality of digital images of the X-ray beam is taken after it has crossed the breast, and a representative image of the contrast produced in the tissues of the breast is calculated from the digital images.

Abstract: An X-ray examination apparatus includes an X-ray source (1) for emitting an X-ray beam (8) having a central X-ray extending along a central beam line (4). There is also provided an X-ray detector (2) for picking up X-ray images. The X-ray source (1) and the X-ray detector (2) are rotatable together around an axis of rotation (3). The X-ray examination apparatus is provided with a calibration system (6, 7). Calibration images of the calibration phantom (6) are formed from different, preferably opposed directions of the X-ray beam (8). The zero orientation of the X-ray source (1) with the X-ray detector (2) is derived from differences in positions of the same aspect of the calibration phantom in the respective calibration images. The central beam line (4) extends perpendicularly to the axis of rotation (3) in the zero orientation.

Abstract: A method of evaluating a substance scoring system comprises acquiring data from a phantom using an imaging system, moving at least a portion of the phantom during the acquiring step, and generating an actual substance score for the phantom based on the data acquired using the imaging system. The phantom simulates a human organ such as a human heart. The phantom is provided with a motion profile that simulates a motion profile of the human organ.

Abstract: A method is described for evaluating substance scoring, the scoring based on imaging system-generated images of an object having regions of interest due to possible presence of the substance, the method including the steps of simulating the regions of interest using a phantom having a plurality of volumes, each volume having dimensions simulating dimensions of a region of interest, each volume having a density representative of a substance density; generating images of the phantom; scoring the substance based on the phantom images; and comparing results of the substance scoring to expected phantom-image results. The above-described phantom and method allow a scoring system user to verify substance scoring accuracy and to compare scores resulting from different imaging systems, scanning methods and reconstruction algorithms.

Abstract: A method of performing bone densitometry, utilizing a dual-energy method, wherein the surrounding soft tissue in the volume of interest is accurately eliminated from the transmission images by means of a calibration procedure. The method utilizes an X-ray apparatus with a two-dimensional X-ray detector so as to perform data acquisition during one run.

Abstract: A method of evaluating a substance scoring system comprises acquiring data from a phantom using an imaging system, moving at least a portion of the phantom during the acquiring step, and generating an actual substance score for the phantom based on the data acquired using the imaging system. The phantom simulates a human organ such as a human heart. The phantom is provided with a motion profile that simulates a motion profile of the human organ.

Abstract: In a method for the operation of a CT apparatus with which volume data for a volume region of an examination subject are registered, markings for identifying reconstruction regions are mixed into an x-ray shadowgram containing the volume region. The reconstruction of image data with respect to each reconstruction region ensues taking reconstruction parameters allocated to the respective reconstruction region into consideration.

Abstract: A method and apparatus are provided for assessing performance of an imaging system. The imaging system has a performance assessment apparatus that comprises a system performance computer configured to execute a performance assessment algorithm. The performance assessment computer is coupled to receive signals from the detector assembly of the imaging array in a plurality of imaging system operating modes so as to identify disparities between actual system performance and nominal system performance for respective ones of the imaging system operating modes and to provide respective system performance output signals.

Abstract: In a mobile X-ray apparatus and a method for determining projection geometries therein, an X-ray system, including an X-ray source and a planar X-ray detector, is provided which is displaceable relative to an examination subject by a displacement arrangement for obtaining a series of 2D projections which are used to construct a 3D image of the subject. Each 2D projection has a projection geometry associated therewith. The X-ray system and the displacement arrangement exhibit mechanical instabilities, due to the light weight construction necessary for mobility of the apparatus, which would preclude accurate identification of the 2D projection geometries. The displacement arrangement therefore includes components for assuring a reproducible displacement movement of the X-ray system, so that projection geometries for respective positions of the X-ray system can be identified in advance, in a calibration procedure, allowing offline determination of the projection geometries.

Abstract: A phantom (50) is positioned on a patient support couch (16) of a diagnostic imaging scanner (10). The phantom includes a plurality of diagnostically imageable elements (52) which are mounted in a fixed relationship such that when projections are made along three orthogonal axes, the projections of the diagnostically elements along each axis are non-overlapping. At least three markers (56) on the phantom are monitored by infrared sensitive cameras (30, 32) or other pick-up devices and the location of the markers in image guided surgery (IGS) space is determined (36). From a priori information about the structure of the phantom, the geometric centers of the imageable elements is determined and projected (64) along the coordinate system axes of IGS space. The phantom is imaged by the diagnostic imaging system to generate projections of the diagnostically imageable elements along each of three coordinate axes of diagnostic image space.

Abstract: A phantom for measuring slice thicknesses, slice sensitivity profiles and the axial modulation transfer function in an X-ray computed tomography apparatus contains a foil of a material that highly attenuates X-radiation that is arranged parallel to the image plane of the X-ray computed tomography apparatus given employment of the phantom and which had an axial expanse that is small compared to the thinnest slice to be measured. The expanse of the foil in the direction of the image plane is on the order of magnitude of a few millimeters.

Abstract: Before a CT scan for a patient, a model that shows transmission lengths of the patient at rotation angles of an X-ray source is stored in a memory. At the CT scan, X-ray tube currents are controlled according to the transmission lengths at the rotation angles in order to apply X-rays to the patient. The three-dimensional model is homogenous and its material is similar to that of the patient's body, and transmission lengths of the three-dimensional model are converted into those of the patient. The model is acquired by a scannography in a single direction or a CT helical scanning with a small X-ray dose. This reduces the X-ray dose applied to the patient.

Abstract: An optical switch includes a core and a fluid reservoir. The core includes a base, a matrix controller substrate, and a planar lightwave circuit. The planar lightwave circuit has a plurality of waveguides and a plurality of trenches. Each trench is located at an intersection of two waveguides. The fluid reservoir supplies a fluid to the plurality of trenches of the core. The optical switch further includes a getter for removing atmospheric gases from the fluid. The getter may be a porous silica getter, a non-evaporable getter, or an evaporable getter. By removing atmospheric gases from the fluid, the getter improves the capacity and operation of the optical switch. The optical switch may further include a membrane to separate the getter in a getter chamber from the fluid in a fluid chamber.

Abstract: An X-ray examination apparatus includes an X-ray source (1) for emitting an X-ray beam (8) having a central X-ray extending along a central beam line (4). There is also provided an X-ray detector (2) for picking up X-ray images. The X-ray source (1) and the X-ray detector (2) are rotatable together around an axis of rotation (3). The X-ray examination apparatus is provided with a calibration system (6, 7). Calibration images of the calibration phantom (6) are formed from different, preferably opposed directions of the X-ray beam (8). The zero orientation of the X-ray source (1) with the X-ray detector (2) is derived from differences in positions of the same aspect of the calibration phantom in the respective calibration images. The central beam line (4) extends perpendicularly to the axis of rotation (3) in the zero orientation.

Abstract: A compensator filter is used to adjust the radiation therapy beam of a linear accelerator device to compensate for tissue that may have been removed surgically. The compensator filter is formed of a plastic material having a density of about one to two times that of the patient's tissue, and is disposed in the filter tray of the linear accelerator for selectively attenuating the radiotherapy beam to compensate for the missing tissue. Preferably, the filter can be made from a blank cast of polyurethane filled with glass microspheres, such that the filter is substantially free of heavy metal substances and toxic materials. The blank can be milled in a compensator filter milling machine of the type that is found in radiotherapy clinics.

Abstract: The quality assurance phantom for intensity-modulated radiation therapy is adapted for use with multiple dosimetric devices, such as ion chambers, MOSFET's, radiochromatic film, and TLDs. The phantom includes a base to which a static block is fixed. A dynamic block is mounted on the base and is adjustably spaced from the static block. A plurality of film dividers are sandwiched between the blocks. After film is inserted between the film dividers, the blocks are clamped together. The static and dynamic blocks include a plurality of cavities for receiving various dosimeters. The dosimeters are interchangeable within the cavities, so as to enhance the versatility of the phantom.

Abstract: In an X-ray computed tomography apparatus with retrospective beam hardening correction, an overall image of a body slice under examination is determined from overall attenuation values that are obtained from the body slice. At least one partial image that shows essentially only one body substance, such as bone substance, is extracted from this overall image. Attenuation partial values are employed for determining a correction value. The attenuation values are determined for each overall attenuation value from the at least one partial image by re-projection. A correction value is derived from the beam hardening error that is determined for a material combination of two different reference materials.

Abstract: It is intended to correctly determine the cerebral blood flow in a successful manner. When a constant &ggr; is determined in a relational expression of {Ka=&ggr;×(1−exp(−Ke/&ggr;))} provided that Ke represents an end-tidal air velocity constant and Ka represents an arterial blood velocity constant concerning a xenon CT examination, a K-S-calculating means determines a temporary calculated value &lgr;&agr; of a brain/blood distribution coefficient &lgr; from temporary calculated values Kai&agr;, Kao&agr; obtained by a Ke/Ka conversion means on the basis of an assumed value &ggr;&agr; of the Ke/Ka conversion constant &ggr; set by an assumed value-setting means. In this case, the assumed value-setting means varies the assumed value &ggr;&agr; within a desired range.

Abstract: A shield is placed on a patient's body over a secondary organ adjacent a target organ. The shield is partially transparent to x-ray radiation. A CT scan of the target organ is conducted according to conventional protocols and technical parameters. No artifacts are formed in the diagnostic portion of the CT image and there is no degradation of the diagnostic portion of the CT image. A reduction of between about 40% and about 60% in the radiation dose of the secondary organ as compared to the same CT scan made without the shield is achieved.

Abstract: Disclosed herein is a phantom for calibrating dual energy x-ray equipment for body fat measurements. In particular, the present invention provides a limited number of calibrated plates of materials simulating different body fat percentages. By combining the plates, a range of simulated body fat compositions may be precisely obtained. The plates may be of arbitrary size to provide a simulation over a broad area and may include a high density end cap for triggering an automatic region of interest detection for certain scanner systems.

Abstract: Device and process for simulating a patient's body for the testing of a three-dimensional vascular X-ray apparatus of the type comprising a means for emitting an X-ray beam, a means for receiving the X-ray beam, a means for displaying the images obtained, and a means for controlling the injection of opacifying liquid into the patient's vessels. The simulation device comprises a stationary part for simulating the patient's bones and soft tissues and a moving part for simulating the patient's opacified blood vessels, so as to be able to perform at least one acquisition of an image of the stationary part alone and at least one acquisition of an image of the stationary part and the moving part, and to obtain an image of the moving part by means of image.

Abstract: Disclosed herein is a spine phantom for calibrating a dual energy x-ray attenuation measurement device for measuring vertebral bone density. Simplified construction of the phantom is made possible by equating the density variations in the three dimensionally complex and inhomogeneous spine as a set of easily machined flat surfaces of different thicknesses. In particular, the spine phantom includes a vertebra-simulating body having a base surface perpendicular to the x-ray beam of the measurement device and defining an intervertebral section, a composite bone section and cortical wall sections. These sections each extend to planes of different heights from the base surface, so as to simulate cartilage, cortical and tabecular bone, and cortical bone wall regions of a human spine, respectively. The spine phantom of the present invention can include multiple vertebra-simulating bodies simulating a range of vertebra types and densities.

Abstract: A method for estimating the bone quality, or skeletal status of a vertebrate on the basis of two-dimensional image data of cortical bone, and which is determined from a density variation of the cortical bone. Intra cortical resorption, scalloping, spongiosation, striation, periosteal resorption, and/or endosteal resorption caused by osteoporosis, osteopenia or hyperparathyroidism may be determined as oblong density variations detected by filtering the image data with two oblong Gaussian kernels (using a Difference Of Gaussian technique) or at corresponding frequencies in the power spectrum.

Abstract: Device for simulating a patient's body for the testing of a vascular X-ray apparatus of the type comprising a means for emitting an X-ray beam, and a means for receiving the X-ray beam after it has passed through a part of the patient's body, the X-ray beam being centered on an axis. The device comprises at least one metal wire disposed at least partially transversely relative.

Abstract: A method and apparatus for calibrating detectors in a computed tomography (CT) system to compensate for differential errors in the detectors are disclosed. Multiple sets of scan data are acquired for a phantom at multiple thicknesses of the phantom. The phantom can be made from multiple slabs of material positioned on the scanner table in a horizontal orientation or in a vertical orientation. Horizontal slabs are removed or added to the stack of slabs to vary the thickness of the phantom. With vertically oriented slabs, each slab is of a different height such that scans of different slabs produce X-ray data for rays having different path lengths and, therefore, attenuations. For each detector, errors in the scan data at the multiple phantom thicknesses are identified and fit to a parametric equation with respect to the log attenuation associated with each thickness. In one embodiment, the parametric equation is a quadratic polynomial.

Abstract: An object (22) is positioned on a patient support (25) between an x-ray source (10) and an x-ray detector assembly (15). The x-ray source (10) is selectively activated to transmit an x-ray beam (20) through an imaging region (32) to the x-ray detector assembly (15). Positioning of the object (22) on the patient support (25) is such that a gap 33 exists in the imaging region (32) through which x-rays may pass unattenuated. An x-ray equalization filter (30) is introduced into the gap 33 and substantially conforms to its shape. The equalization filter (30) comprises a fluid medium disposed in a flexible receptacle. The fluid medium contains x-ray attenuating material suspended in a gel base. Placement of the equalization filter (30) in the gap reduces the number of unattenuated x-rays reaching the x-ray detector assembly (15) thereby enhancing image quality.

Abstract: A transparent measuring phantom apparatus and method facilitates rapid testing of the accuracy and repeatability of the scan position mechanisms of patient support table movements of computer assisted tomography (CAT) and magnetic resonance imaging (MRI) systems. The phantom includes clear transparent acrylic sections and radiopaque acrylic numerals which are all adhesively or solvent bonded into the phantom. The phantom includes an acrylic tube enclosing a base plate, a longitudinally extending slice location bar, a plurality of sequential position indicator numerals and operator position indicator numerals between a pair of end plates. The slice locator bar has an array of slice locator holes. In operation, the long axis of the phantom is aligned with the long axis of table movement that determines the slice location. The slice locator holes are drilled into the slice locator bar in a repeating pattern.

Abstract: A quality assurance test phantom having a shell wherein water and test objects reside in conjunction with a bellows capable of longitudinally translating one or more of a variety of test objects within the inside of the phantom via a screw mechanism is described. These test objects are employed in novel tests to quantitatively evaluate the imaging performance of a computed tomography ("CT") device with specific regard to the construction of pseudo-planar slices produced from scan data taken using helical scanning techniques.

Abstract: In an improved CT scanner calibration method and apparatus, a radiation beam, for example an x-ray beam, is directed at a plurality of radiation detectors. The beam is attenuated by a phantom of known attenuation characteristics. The detectors generate measured attenuation data from the attenuated beam. The measured attenuation data is back-projected to generate a measured phantom image. The measured phantom image is converted to an ideal phantom image. The ideal phantom image is forward projected to generate ideal attenuation data. Calibration values for each detector channel in the scanner are generated by cross-referencing the ideal and measured attenuation data. In a preferred embodiment, this cross-referenced data is compressed and stored in a look-up table for referencing during later interrogation of subjects.

Abstract: A phantom apparatus for measuring the radiation dose distribution produced by a brachytherapy device used to treat a localized area with radiation. The brachytherapy device includes an insertable probe capable of producing predefined radiation dose geometries about a predefined point. The phantom apparatus includes a tank containing a medium having a radiological equivalent characteristic of the localized area to be treated. The phantom apparatus also includes a radiation sensor for measuring the radiation dose and a positioning system for moving the probe with respect to the radiation sensor. The radiation sensor is also coupled to a positioning system to orient the sensor for optimal dose measurements. The phantom apparatus includes a control system that coordinates the movements of the probe and the radiation sensor to avoid a collision. The control system moves the probe along a predefined path around radiation sensor and records the dose at predefined points along the path.

Abstract: A method of generating an image representing fat distributions, comprising the steps of scanning two different levels of tube voltage using a phantom containing a sample rod of a fat standard material and a plurality of sample rods with different densities of a bone mineral equivalent material, to generate two cross sectional image data; detecting the CT number of each pixel in an entire region or an objective region of the cross sectional image data as the CT number of a tissue including fat (.alpha.wf); detecting the CT number of the bone mineral equivalent material to calculate a linear regression between the CT number and the density of the bone mineral equivalent material and to define the CT number of a tissue excluding fat (.alpha.nf); detecting the CT number of the fat standard material (.alpha.ff), while detecting the CT number of a soft tissue standard material (.alpha.st), wherein individual CT numbers are applied to the equation.alpha.wf=.alpha.nf+.beta..multidot.(.alpha.ff-.alpha.st)with .beta.

Abstract: A calibration template 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: In a method for acceptance and stability testing of filmless dental radiographic equipment a test measurement body having a plurality of absorption elements which absorb differently is arranged in the beam path of the X-rays at a defined close distance from a radiation-sensitive sensor. The electric signals obtained from the sensor are fed to a computing unit which processes these to form image value signals which are then fed either directly to a display unit or are firstly compared with prescribed desired image values and, in the case of deviations, fed to the display unit. The test measurement body includes a holder for reproducibly holding a sensor which can be applied intraorally to a patient.

Abstract: A method for quantitatively determining bone mineral mass by a CT system, comprising scanning an objective region together with a plurality of samples produced by mixing a water equivalent material with various ratios of a standard material equivalent to bone mineral mass and determining the bone mineral density of the objective region with reference to the CT numbers of the samples, wherein a plurality of samples are scanned together with the objective region at one or multiple levels of tube voltage and a corrected CT number of each sample is calculated by substituting the CT number of each of the samples with the CT number of blood or a standard material equivalent to blood. By scanning at a single level of tube voltage, bone mineral density is determined, on the basis of the CT number of the objective region and with reference to the corrected CT numbers.