EXTERNAL RADIATION DOSE MEASUREMENTS AND PROTECTION MEASURES DURING SCINTILLATION SCANNING

In this study, we tried to measure the external dose surrounding the patient after getting in position for scintillation scanning and hence tried to measure the amount of dose intaken by the technicians. We selected the patients in nine groups, depending on the organ of experiment. The included experiments are: Thyroid scanning by "Tc-pertechnetate, liver-spleen scanning by 99mTc-sulfur-colloid, heart scanning by 99mTc-MIBI and 201TI, kidney scanning by 99mTc-DTPA, whole body bone scanning by 99mTc-MDP, brain scanning by 99mTc-DTPA, soft tissue scanning by 67Ga, and thyroid cancer scanning by 131I. We selected 10 patients from each group and measured the activity by Eberline ESP-2 GM counter at distances 0.25 m, 0.50m, 1 m and 2 m. Considering 1m distance as standard, we found the minimum dose 0.89±0.01 mR/hr during thyroid scanning and the maximum dose 1.8±0.01 mR/hr during heart scanning. These findings satisfy the ICRP code of practice for radiation workers. But we should remember that, this dose only includes the time of acquisition. If we include the dose during injection, then the dose must be higher than the present value. So it is suggested at least two technicians to attend in rotation especially for heart scanning.

Keywords: radiation dose, scintillation scanning, external radiation dose measurement