Radionuclide purity and dosimetry related to the medical use of the radionuclides Fe-52, Tc-99m and I-123

Extensive use is now being made in clinical medicine of radionuclides with short half-lives, of a few hours, which can be administered to patients in activities of several millicuries. This thesis is concerned chiefly with experimental studies of the dosimetry associated with the use of three radio-nuclides of this type: 52Fe, sup(99m)Tc and 123I. Radionuclide impurities in these radionuclides were studied using semiconductor and scintillation counter spectrometers. For sup(99m)Tc and 99Mo-sup(99m)Tc generators, several relatively long-lived contaminants were found including 131I, 103Ru, 192Ir, 60Co, 54Mn, 134Cs and 110Ag. Experiments to establish the maximum levels of contamination with alpha emitting radionuclides in the eluates from certain generators are described. Similar studies of 123I and 52Fe manufactured in a cyclotron showed chiefly radio-isotope impurities. Contributions to dose to the patients from these radionuclides were calculated. Different methods of calculating the absorbed dose from internal administration were compared. The use of lithium fluoride TLD in the measurement of dose received by staff handling these radionuclides, and the protection afforded by shielded syringes were studied. Direct measurements were made, using TLD, on patients administered sup(99m)Tc, and and attempt has been made to correlate calculations of dose to certain sites of the body with the results of these measurements. 8author)