Bernard E. Oppenheim

More accurate algorithms for iterative 3-dimensional reconstruction

A work-in-progress report is presented dealing with several methods of iterative 3-dimensional reconstruction that are more accurate than the usual methods, and the behavior of a number of algorithms upon varying the number of iterations, the number of projections, the counts per projection, and the field of view of the detector.

A Simple Device for Reducing Motion Artifacts in Gamma Camera Images

Abstract Respiratory motion represents a major limitation in high-resolution imaging with radionuclide tracers. The authors describe a simple circuit which uses the Anger camera itself to sense organ motion and generates a correction signal which compensates for this motion. The resultant image demonstrates dramatically reduced blurring. This device can be. useful in conjunction with high-resolution camera systems.

What Causes Lower Neck Uptake in Bone Scans

Lower neck uptake, frequently seen on anterior views of bone scans done with 99mTc-phosphate compounds, was studied in 122 patients to determine its incidence and etiology. Increased uptake was identified in the lower neck anteriorly in 46 patients (38%). In 14 of these, moderately severe to severe arthritis appeared to cause the uptake; metastatic disease was the cause in 8 cases; and in 1 case there was prominent uptake in the thyroid cartilage. Positioning artifact accounted for the uptake in the other 23 cases. Thyroid uptake was never observed.

Nuclear Imaging: A New Dimension

Tomographic techniques used in radiology have also found an application in nuclear medicine. Longtitudinal tomography blurs but does not eliminate structures outside the plane of interest. Transverse tomography eliminates out-of-plane structures, making accurate imaging possible. Positron imaging devices are well suited for transverse tomography because of their high spatial resolution and depth-independent response, but devices using a scintillation camera can visualize large volumes and are not restricted to the use of positron emitters.

High-contrast film copying for thallium 201 cardiac image processing

To evaluate the usefulness of high-contrast film copying as an economical means of enhancing contrast in thallium 201 cardiac images, stress and rest studies of 47 patients with and 19 patients without coronary artery disease were evaluated. A total of 66 sets of four different image formats were independently interpreted by five observers. The analysis of the receiver operating characteristic curves suggested that the high-contrast film copies were superior to their original analog images and comparable with computer-processed images in diagnostic yield. It appears that contrast enhancement by simple film copying can improve the accuracy of 201Tl image interpretation.