The count rate performance of a multiwire gamma camera measured by a decaying source method with 9.3-minute tantalum-178.
The multiwire gamma camera (MWGC) operates at high count rates with radionuclides of low energy and short half-life. We evaluate the count rate performance of the MWGC with tantalum-178 (178Ta) by a decaying source method. Data acquired dynamically by the camera from a 178Ta source in the NEMA Standards scatter phantom were corrected for deadtime loss by a trial paralyzing deadtime and converted to their natural logarithms. The trial deadtime, tau, was adjusted iteratively after curve fittings until a straight line was achieved. The paralyzing deadtime determined by this method was 0.41 microsecond. Therefore, the camera can be operated up to 850,000 cps with 178Ta without exceeding 50% data loss. This rate is 10 times greater than the performance of the typical scintillation camera. Moreover, high count rates are achieved without significant loss of spatial resolution.
Loma Linda University, California 92354.
R
R
Adams
J L
JL
Lacy
M E
ME
Ball
L J
LJ
Martin
D005069:Evaluation Studies as Topic; D015902:Gamma Cameras / Q000592:standards*; D011868:Radioisotopes; D013635:Tantalum
D011868:Radioisotopes; D013635:Tantalum