Multiple Radioisotopes Research Articles

Semiconductor Gamma-Cameras in Nuclear Medicine

The availability of semiconductor detectors, principally High Purity Germanium, permits consideration of new generations of nuclear medicine imaging devices. These are characterized by excellent spatial resolution and by simultaneous multiple radioisotope imaging capabilities. The technology and some of its resultant benefits are presented here.

An analysis of errors in a technique for the combined use of multiple radioisotopes

The ability to maintain a small error was uncertain in a technique which involved the simultaneous use of five radioisotopes. A systematic in vitro investigation was undertaken to assess the technical errors and the total error in the technique. Technical errors in counting activity, pipetting samples, and measuring tracer volumes were determined separately. Sixty-eight determinations of five known volumes of water were made to evaluate the total error. The results of the in vitro volume estimates were submitted to statistical analysis. Four questions were asked. (1) Was there a significant difference between the estimated volumes obtained by the five isotopes and the known volumes? (2) Was there a significant difference between the estimated volume obtained with each isotope and that obtained with the other isotopes? (3) Were all the volume levels studied estimated with the same degree of accuracy by either of the five isotopes? (4) Can changes in volume of ten percent, at levels of 2 1. and 10 1., be estimated with sufficient accuracy to enable quantitative statements to be made about estimates of equivalent changes in physiological volumes? The technical errors in the technique were small resulting in an average total error of 0·85 percent between the known and estimated volumes using pooled data. Either isotope was found to be equally as accurate as the other isotopes in estimating any of the volumes studied. This in vitro assessment of errors indicates the techniques to be sufficiently accurate and reproducible to be utilized in a quantitative estimate of changes in physiological volumes.