Abstract: Computer control of a multi-axis radiographic instrument is utilized to prevent contact between moving surfaces of the instrument based on soft limits. The soft limits are established from a legal state table incorporating all combinations of axis movement of the equipment and relating those combinations to contacting or non-contacting states. The legal state table may be used to map efficient paths between a start and ending position and may be augmented with non-contacting transducers which may sense patient movement not incorporated into the legal state table.

Abstract: A CT apparatus for scanning compact structures associated with a larger body uses radiation source producing a reduced field-of-view to simplify construction and reduce exposure of the larger body. Truncation artifacts in the reconstructed image caused by volume elements in the larger body imaged by the radiation beam only for projections at some angles, are reduced by acquiring two projections at two different energies and combining those projections to compensate for the attenuation of the radiation by the volume elements of the larger body.

Abstract: An ultrasound densitometer is disclosed in which ultrasonic transducers are located spaced apart in a water bath into which the heel of a person may be inserted. The transit time of an ultrasonic pulse through the water and heel and the attenuation of the pulse may be measured to evaluate the physical properties of the bone in the heel. A central controller coordinates the ultrasonic measurement with the automatic filling and draining of the water bath to ensure hygienic and repeatable operation. The water may be preheated to reduce patient discomfort and to improve the reduced by preheating water in a separate pre-fill chamber during the previous scan. Gravity feed of the water reduces the complexity of the water handling and provides extremely quiet operation. A toe peg in the water bath, which fits between the patient's toes, and a calf support help to reduce patient motion during the measuring.

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: A method of evaluating bone density around a radiolucent composite prosthesis establishes an implant boundary by fitting a stored template to radio-opaque reference markers embedded in the prosthesis. The implant boundary is used to create a measurement boundary displaced from the implant boundary toward the bone producing a conformal region of interest. Matched histograms of bone density in a lateral and medial such region of interest may be displayed to evaluate symmetrical stress effects. Alternatively, bone density may be displayed plotted along an axis cutting across the medial and lateral sides. Fiducial points are identified from the bone and implant morphology to ensure that either display will have a repeatable reference and hence that such displays will be directly comparable to later and earlier displays thereby aiding in the detection of bone change.

Abstract: An ultrasound densitometer is disclosed in which ultrasonic transducers are located spaced apart in a water bath into which the heel of a person may be inserted. The transit time of an ultrasonic pulse through the water and heel and the attenuation of the pulse may be measured to evaluate the physical properties of the bone in the heel. A central controller coordinates the ultrasonic measurement with the automatic filling and draining of the water bath to ensure hygienic and repeatable operation. The water may be preheated to reduce patient discomfort and to improve the consistency of the result. The delay of preheating is reduced by preheating water in a separate pre-fill chamber during the previous scan. Gravity feed of the water reduces the complexity of the water handling and provides extremely quiet operation. A toe peg in the water bath, which fits between the patient's toes, and a calf support help to reduce patient motion during the measuring.

Abstract: Method of increasing the strength of contraction in the mammalian heart muscle by administering to the mammal an effective amount of an activated Vitamin D compound, i.e. a 1.alpha.-hydroxylated Vitamin D compound which binds with the Vitamin D receptor and produces a positive inotropic effect in the heart muscle. The activated Vitamin D compound may be given as a means to treat myocardial failure.

Abstract: An ultrasound densitometer is disclosed in which ultrasonic transducers are located spaced apart in a water bath into which the heel of a person may be inserted. The transit time of an ultrasonic pulse through the water and heel and the attenuation of the pulse may be measured to evaluate the physical properties of the bone in the heel. A central controller coordinates the ultrasonic measurement with the automatic filling and draining of the water bath to ensure hygienic and repeatable operation. The water may be preheated to reduce patient discomfort and to improve the consistency of the result. The delay of preheating is reduced by preheating water in a separate pre-fill chamber during the previous scan. Gravity feed of the water reduces the complexity of the water handling and provides extremely quiet operation. A toe peg in the water bath, which fits between the patient's toes, and a calf support help to reduce patient motion during the measuring.

Abstract: A method of evaluating bone density around a prosthesis establishes an implant boundary at the edge of the prosthesis and creates a measurement boundary displaced from this implant boundary toward the bone producing a conformed region of interest. Matched histograms of bone density in a lateral and medial such region of interest may be displayed to evaluate symmetrical stress effects. Alternatively, bone density may be displayed plotted along an axis cutting across the medial and lateral sides. Fiducial points are identified from the bone and implant morphology to ensure that either display will have a repeatable reference and hence that such displays will be directly comparable to later and earlier displays thereby aiding in the detection of bone change.

Abstract: A scanning radiographic densitometer constructs a broad area, two dimensional projection image from a combination of a set of smaller fan beam scans by tilting the axis of each such smaller scan to construct an effective larger fan beam to reduce artifacts caused by height dependant overlap of the multiple fan beams. The data is projected to a non-planar image surface to eliminate local area distortion such as may cause error in density measurements and to permit some overlap without height sensitive effects.

Abstract: A CT apparatus for scanning compact structures associated with a larger body uses radiation source producing a reduced field-of-view to simplify construction and reduce exposure of the larger body. Truncation artifacts in the reconstructed image caused by volume elements in the larger body imaged by the radiation beam only for projections at some angles, are reduced by acquiring two projections at two different energies and combining those projections to compensate for the attenuation of the radiation by the volume elements of the larger body.

Abstract: A method for the derivation of indicia of vertebral morphology from data obtained by lateral digital scans of the vertebrae obtains a matrix of data values assembled from a lateral vertebral scan. The matrix is analyzed to locate local minima and maxima from which the borders of the vertebral body may be calculated. Once the borders of the vertebral bodies are derived, one or more of several useful indicia of vertebral condition can be calculated. These indicia are associated with clinically recognized modes of vertebral condition. The data values in the matrix are also scanned for areas of unusual densities so that nonhomogeneous regions are not used in measuring overall bone mineral density of a vertebra.

Abstract: A desitometer gantry may translate in two directions for scanning and may swivel about a vertical axis to allow the radiation angle and the detector-to-patient distance to be altered during a scan so as to provide constant magnification of the image and to align the patient's spine with the radiation beam for more accurate edge measurements. A method of reducing the effects of osteophytes on density measurements applies an iterative threshold based on the density difference between hard and soft tissue.

Abstract: A dual energy x-ray system for determining bone density and the like compensates for variable flux density associated with the different absorptions and the production of the high and low energies of x-rays by controlling both the voltage biasing the x-ray tube and the relative dwell times during which the x-ray tube is at those voltages, the dwell time being increased for the lower voltage to compensate for lower flux density. Compensation for variations in flux density improves the resultant signal-to-noise ratio of the measurements taken and thereby provides more accurate measurement of materials with minimized examination time.

Abstract: A method for the derivation of indicia of vertebral morphology from data obtained by lateral digital scans of the vertebrae obtains a matrix of data values assembled from a lateral vertebral scan. The matrix is analyzed to locate local minima and maxima from which the borders of the vertebral body may be calculated. Once the borders of the vertebral bodies are derived, one or more of several useful indicia of vertebral condition can be calculated. These indicia are associated with clinically recognized modes of vertebral condition. The data values in the matrix are also scanned for areas of unusual densities so that nonhomogeneous regions are not used in measuring overall bone mineral density of a vertebra.

Abstract: An instrument for measuring the strength and integrity of bone in vivo by ultrasound pulse taking its data by measurement of the os calcis or heel bone. The measured data is processed so that the instrument is capable of presenting its output in units of estimated spinal bone density, a value of recognized clinical value and acceptance. It has been determined that, using both the changes in the speed of ultrasound in the patient's heel and the broadband ultrasonic attenuation of the ultrasonic pulse as it transmits through the patient, that a value for estimated spinal bone mineral density can be calculated which correlates very well with actual measured values of spine mineral density.

Abstract: An ultrasound densitometer for measuring the physical properties and integrity of a member in vivo includes a transmit transducer from which acoustic signals are transmitted, and a receive transducer which receives the acoustic signals after they have been transmitted through the member and/or a material with known acoustic properties. The densitometer allows the physical properties of a member to be measured without having to determine the distance between the transducers. The densitometer is able to measure the physical properties and integrity of the member from the transit time of acoustic signals through the member and/or by determining the absolute attenuation of at least one specific frequency component of acoustic signals transmitted through the member.

Abstract: An ultrasound densitometer for measuring the physical properties and integrity of a member in vivo includes a transmit transducer from which acoustic signals are transmitted, and a receive transducer which receives the acoustic signals after they have been transmitted through the member and/or a material with known acoustic properties. The densitometer allows the physical properties of a member to be measured without having to determine the distance between the transducers. The densitometer is able to measure the physical properties and integrity of the member from the transit time of acoustic signals through the member and/or by determining the absolute attenuation of at least one specific frequency component of acoustic signals transmitted through the member.

Abstract: An ultrasound densitometer for measuring the physical properties and integrity of a member in vivo includes a transmit transducer from which acoustic signals are transmitted, and a receive transducer which receives the acoustic signals after they have been transmitted through the member and/or a material with known acoustic properties. The densitometer allows the physical properties of a member to be measured without having to determine the distance between the transducers. The densitometer is able to measure the physical properties and integrity of the member from the transit time of acoustic signals through the member and/or by determining the absolute attenuation of at least one specific frequency component of acoustic signals transmitted through the member.

Abstract: An ultrasound densitometer is disclosed in which ultrasonic transducers are located spaced apart in a water bath into which the heel of a person may be inserted. The transit time of an ultrasonic pulse through the water can be compared to the time for a similar pulse with a heel inserted. A novel clinical indicia for bone integrity value has been developed to provide a single numerical indication related both to the speed of sound travel in the member and the ultrasonic broadband attenuation in the member. The bone integrity value numeral based on measurements in the os calcis has been found to correlate well with conventional measurements of spinal bone mineral content.