Source of Support: None, Conflict of Interest: None
The effect of radiation detector positioning over liver and spleen containing Fe-59 radioactivity, on its response has been investigated using water filled PVC elliptical cylinder as upper abdomen (UA) phantom and lucite Alderson phantoms of liver and spleen. Significantly large and rapid variation was exhibited when the detector moved around the reference point over the spleen. No significant difference in response could be found when the detector moved around the reference point over the liver. The effect of organ volume on detector response as well as on its contribution in the count rate of neighbouring organ was investigated using rubber balloon of appropriate volume. As a consequence of the study it was possible to mark on the abdomen phantom an area wherein if the detector pointed to spleen measurement, the contribution from liver radioactivity in the form of scattered radiation will be < 15%.