A system for tracking fast motion in human joints using high frame rate digital radiography

Michael J. Flynn, Scott Tashman, Frank Cverna, Kevin Dupre, Kevin Albright, David A. Reimann, and Roger Block

In 1994 IEEE Nuclear Science Symposium and Medical Imaging Conference, Norfolk, Virginia, 30 October-5 November 1994.

Rapid, complex motions in human joints are believed to contribute to the development of osteoarthrosis and bone mineral erosion. To study these motions we are developing a biplane digital radiography system to record internal joint movements during running impact or atheletic limb articulation. A specialized gantry has been developed to permit two radiographic views 45 to 90 degrees apart in the horizontal plane. Presently, images are recorded from conventional image intensifiers using synchronized square wave pulses of radiation lasting about .3 seconds and exposing the object to about 75 mR of radiation. During this pulse, digital images have been recorded using a CCD device operating at 250 frames per second or by using a vidicon device operating at 1000 frames per second. Frames have been successfully recorded with camera gates as short as .1 msec. Measurement of 27.6 meter per second velocities with a 1 percent precision have been experimentally demonstrated. This system presently records kinetic biomedical data 10 times faster than conventional cineradiography methods used for cardiac imaging. Further improvement is possible using pulsed x-ray sources and multi-port, high frame rate CCD detectors.

Copyright © 1994, David A. Reimann. All rights reserved.