Documents thyroid cancer 4 results

"Thyroid nodules and thyroid cancer occur more frequently in people exposed to radiation for therapeutic purposes, and to nuclear fallout. Furthermore, it is known that a moderate degree of iodine deficiency may be responsible for an increased prevalence of thyroid nodules, while it is suspected that radiation exposure could induce changes in thyroid autoimmunity. The iodine intake of people resident in Bari, S. Italy, is mildly deficient, which could be presumed to cause a higher prevalence of thyroid pathology. This study was conducted to evaluate the prevalence of thyroid nodules in a population occupationally exposed to radiation, in an area of mild iodine deficiency."

"Information about the consequences of human exposure to radiation in the former Soviet Union has recently become available. These data add new insights and provide possible answers to several important questions regarding radiation and its impact on occupational and public health. The 1986 Chernobyl accident initiated a major and early increase in childhood thyroid cancer that resulted from ingestion of iodine-131 (131I) by young children living in the most heavily contaminated areas of Belarus, Ukraine, and Russia. No significant additional cancer or other adverse medical effects have yet been reported in the affected populations and among clean-up workers. Major psychological stress independent of radiation dose has been observed in those people thought to be exposed. During the early days of the atomic energy program in the former Soviet Union, some unfortunate events occurred. The country's first atomic test in Semipalatinsk in 1949 exposed over 25,000 people downwind from the blast to significant doses of fission products, especially 131I. During the late 1940s and the early 1950s nuclear material production facilities were developed near Chelyabinsk in the South Ural Mountains, which resulted in major releases into the environment and significant overexposures for thousands of workers and nearby populations. ..."

"Background
Reconstruction and analysis of low doses received by the occupationally exposed medical radiation workers, especially nuclear medicine staff dealing with radioisotopes may significantly contribute to the understanding of radiation impact on individuals, assess and predict radiation related risks for the development of cancer or other specific diseases.
Methods
A pool of 2059 annual effective doses corresponding to 272 job's positions occupied by nuclear medicine and radiology workers for a certain time period over 26 years in five Lithuanian hospitals was investigated in order to analyze the occupational exposure tendencies to medical staff. Requested data, measured in terms of whole body dose, personal dose equivalent Hp(10), was obtained from the National Register of Sources of Ionizing Radiation and Occupational Exposure. Considering that nuclear medicine staff is dealing with open sources/radioisotopes, doses to extremities, Hp(0.07), were measured using thermoluminescent dosimeters (TLD) of LiF:Mg, Ti type. Lifetime risk estimations for the development of specific cancer (thyroid cancer and leukemia) for exposed radiation workers were performed using risk models included in BEIR VII report (BEIR VII, 2006). The conservative assessment of the thyroid exposure was performed using RadRAT 4.1.1 tool.
Results
Doses to radiology technologists and radiology nurses were found to be highest over the years. However, their annual doses never exceeded dose limit of 20 mSv and were following the same decreasing tendency as the doses of other personnel. There was no increase of doses to nuclear medicine staff observed after installation of two new PET/CT machines, indicating increased radiation protection culture and application of relevant technical and protective measures by the staff. Measured fingertip doses were 2–3 times higher than the hand doses measured with TLD ring and were dependent on the type and frequency of the nuclear medicine examination procedure and on the type and activity of isotopes used for examination.
Conclusions
For the first time, retrospective dose evaluation for the cohort of medical radiation workers was performed in the country. It enabled estimation of lifetime attributable risk for the development of two cancer types: thyroid and leukemia cancer among occupationally exposed medical radiation staff. Projected risk was low, ~10−5, however it was found that the risk of thyroid cancer for female staff was 5.7 times higher than for the males. Obtained results will be used for the predictive assessment of possible radiation induced health effects to occupationally exposed medical radiation workers."