Lunar Corporation

Joseph P Bisek

Richard B Mazess

David L Ergun

James A Hanson

Robert A Washenko

Jixing Chen

An accessory for fluoroscopy equipment is provided to support the x-ray tube and detector on a pedestal with respect to a patient limb for quantitative bone densitometry measurement. Software loaded into the associated digital imaging fluoroscopy equipment provides necessary correction of the images for the quantitative accuracy needed for bone densitometry. Alternatively, a specialized detector or extremely low form factor image intensifier may be inserted in the pedestal to be used in lieu of the fluoroscopy equipment detector. A similar software correction is performed on an associated computer when a separate detector must be used.

Densitometry adapter for compact x-ray fluoroscopy machine

A short form intensifier is provided having a plurality of cameras each providing a portion of the image of the image intensifier to reduce the focal length and hence the distortion of each camera individually. The images may be collected to provide a single contiguous image. Multiple lenses may be associated with different correction factors in associated correction circuitry.

Multi-mode x-ray image intensifier system

A scanning densitometer provides transverse scanning of the patient with a small angle fan beam to significantly reduce parallax and image overlap blurring. Additional reduction of artifacts in the region of combined scans is obtained by a varying overlap of the scans when they are merged determined by a best matching of an identified structure within the scan. The matching process which reveals an ideal overlap provides height data of the structure allowing correction of magnification for structures which change in height within the patient over the scan.

Transverse scanning densitometer

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.

Method for periprosthetic bone mineral density measurement

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.

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.

Growing community of inventors

Madison, WI, United States of America

Joseph P Bisek