ABSTRACT
Objective:To understand the 131I activity in thyroid of therapy workers in nuclear medicine department, and estimate the annual committed effective dose, in order to analyze the internal exposure of them. Methods:Six hospitals were investigated and 131I activity of thyroid was measured. The detection rate and activity value of thyroid 131I activity of therapy workers in nuclear medicine department were obtained from the six hospitals, and then the intake and annual committed effective dose were calculated. Results:A total of 63 iodine therapy workers from six hospitals were measured and 131I was detected for 52 workers among them, with the detection rate of 83% and 131I activities mostly lower than 200 Bq. The estimated annual committed effective dose ranged from 0.23 to 7.78 mSv. The annual committed effective dose to 84.6% of the workers was less than 2 mSv. Conclusions:Iodine therapy workers in nuclear medicine department should receive routine internal exposure personal monitoring, and the radiation protection system in all hospitals needs to be further improved.
ABSTRACT
Objective:To investigate 131I activity in thyroid of workers at the place of radioiodine therapy and its main influencing factors. Methods:In terms of the types of hospitals, six hospitals that performed radioiodine therapy procedure were selected by quota sampling in the provinces of Shandong and Shanxi. 131I activity in thyroids of 76 workers at the place of radioiodine therapy was measured directly, and their internal doses were estimated. Results:131I activity in thyroids was found to be above the detection limit for 29 subjects (38.16%) in five hospitals. The maximum value of 131I activity was 2 468.45 Bq for a doctor who was responsible for manual distribution of radioisotopes. In general 131I activities in thyroid of workers at the place of radioiodine therapy of six hospitals were not significantly different ( P>0.05). But the measurement result in the hospitals where radioiodine was distributed manually were significantly higher than that in the hospitals where radioiodine was distributed automatically ( Z=1.75, P<0.01). Thyroid measurement result of 12 workers in two hospitals where radioiodine was distributed manually were all above the detection limit, with medians of 324.59 Bq and 331.98 Bq, respectively. The medians of 131I activities in thyroid of 12 staff in the remaining 4 hospitals were all below the detection limit. The detection frequencies of 131I above dose limit were 32.61%, 25.00%, 10.00% and 0. The measurement result for the doctors who participated in distributing 131I and the relevent cleaners were significantly higher than for the doctors who did not participate in distributing 131I at the same hospital ( Z=2.44, 2.12, P<0.05). Conclusions:There was a significant difference in the internal exposure level among workers at the different places of radioiodine therapy. Using automatic loading device could reduce the internal exposure level of the workers at the place of radioiodine therapy. It is necessary to strengthen the radiological protection for workers at the control area of the place of radioiodine therapy.
ABSTRACT
Objective:To understand the activity concentration of 131I aerosol in the air of the iodine treatment workplace and estimate the internal dose of 131I inhaled by medical staff in nuclear medicine. Methods:Using CF-1001BRL portable large capacity air sampler, the 131I aerosol in the iodine treatment workplace of nuclear medicine department of 6 hospitals in Shandong province was collected by iodine box, and the HPGe-γ energy spectrometer was used to measure the samples. The 131I activity concentration in iodine treatment workplace at 6 hospitals was obtained, and the internal dose to medical staff was estimated. Results:The 131I activity concentration in the air in iodine treatment workplaces at 6 hospitals ranged from 3.64 to 2.94×10 3 Bq/m 3. The 131I activity concentration in the controlled area (ward, patient passageway, subpacking room, operation administration room) was significantly higher than that in the supervised area. The highest 131I activity concentration, 2.62×10 2 Bq/m 3, in the supervised area was found in the medical care passageway. The estimated effective dose to nuclear medicine workers was 0.07-5.68 mSv, not exceeding the national limit. Conclusions:The phenomenon of 131I aerosol contamination still exists in the iodine treatment workplaces of nuclear medicine departments in hospitals, so it is necessary to carry out internal radiation monitoring for nuclear medicine departments all around the country, and explore more reasonable protection standards and methods.