Abstract
Radioisotope which is produced by milking system is first measured its activity and then prescribed for a patient. For this measurement, a radioisotope calibrator is used. At this time, correction of nuclide, activity, and location of the test material in the well is required. We checked our two ionization chambers and a scintillation calibrator on the measurement error brought about by different radioisotope volume and container. For this purpose, we studied isodose curve, depth where real figure appears, and variation of the indicated value with time. As a result, we found out that there exists twice as much difference regarding the sensitivity depend on the depth in the well. And also, two apparatus of same type showed different isodose curve. Enlargement of the volume of the test material also caused error. Isotope is usually contained in a syringe or vial when they are come into use. Here, sensitivity differes with the shapes of these containers as well as the quantity of the liquid in them. After this study, we can say that at Tc-99m, nearly 20% error is enevitable. At this study, we made a chart to bring out a correction coefficient for each measuring apparatus to correct these errors caused by different volume and different containers. This paper reports the necessity of these error corrections, accuracy, and everyday checking.
