Radiation Levels from Toilets Used By Patients Injected with 99mTc-based Radiopharmaceuticals in Ibadan

OBJECTIVE The use of radionuclides in patients undergoing nuclear medicine procedures presents a special concern on the safety of not only the patients but also of those who come in contact with such patients either at the nuclear medicine centre or at home after discharge from the facility. This has heightened the public concern about nuclear medicine especially in Nigeria where the practice is new. When patients are injected with radioactivity for nuclear medicine procedures they excrete most of the radioactivity via urine even before leaving the nuclear medicine facility. Therefore, we set out to survey the toilets used by these patients in the hospital for radiation levels to know the radiation risk posed by the 'radioactive urine' of the patients to the general public and radiation workers respectively. METHODS A portable digital radiation survey meter was used for measurement of radioactivity in toilets used by a total number of 202 patients injected with 99mTc-based radiopharmaceuticals over a period of 60 days for the level of radioactivity. RESULTS The minimum background radiation level measured was 0.18 µSv/h while the maximum was 0.44 µSv/h and the mean background reading was 0.28 µSv/h. The readings recorded for the male toilets were: 0.1 µSv/h minimum, 5.62 µSv/h maximum with a mean of 0.52 µSv/h while those for the female patients were 0.19 µSv/h minimum, 21.73 µSv/h maximum and a mean of 3.3 µSv/h. CONCLUSIONS In conclusion, the radiation levels from toilets used by patients injected with 99mTc-based radiopharmaceuticals were within reasonable and acceptable limits and do not pose significant radiation risk to others.