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The International Workshop on Radiation and Thyroid Cancer (Day 2 ) Dose EstimationEffects Identification Dose Response Relationship Risk Estimation.

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Presentation on theme: "The International Workshop on Radiation and Thyroid Cancer (Day 2 ) Dose EstimationEffects Identification Dose Response Relationship Risk Estimation."— Presentation transcript:

1 The International Workshop on Radiation and Thyroid Cancer (Day 2 ) Dose EstimationEffects Identification Dose Response Relationship Risk Estimation

2 Session 2: Dose Estimations for Those Affected in Fukushima Prefecture Dose estimations by WHO, FMU, NIRS, and Hirosaki Univ. were presented. The more recent estimations (FMU, NIRS, Hirosaki Univ.) are lower than the WHO value. External doses, for the first four months, have been estimated for more than 470,000 respondents from the Basic Survey. The effective dose distribution (excluding workers): <1 mSv, 66.3%, <2 mSv, 94.9%, <3 mSv, 99.3%

3 Session 2: Dose Estimations for Those Affected in Fukushima Prefecture Independent estimations indicated that the internal thyroid doses were around 30 mSv at 90 percentile for small children in relatively high dose areas. Individual determinations of thyroid dose are important to be communicated back to the individual so they can make informed decisions about the management of their health. To improving the dose estimation; Clarification on the source term, the ratio of radioactive Iodine to Cesium. Additional analyses, e.g. combination of internal dose measurement and evacuation routes of the evacuees.

4 Session 3: Thyroid Ultrasound Examinations and Thyroid Cancers Thyroid ultrasound examinations has been started on all children in the Fukushima Prefecture. There has been an increase in childhood thyroid cancer in prefectures far from Fukushima and in Korea. Base-line vs Radiation-associated Thyroid Cancer: Dose-response relationship. Latency period ( 4 to 5 years for radiation-induced thyroid cancer ) Age distribution (More in younger, if radiation-induced) What is being seen now should be used as the baseline for thyroid cancer into the future.

5 Session 4: Thyroid Cancer Risk Estimates Experts expect an incidence of thyroid cancer, after 1 st screening of 0.3 cases per 100,000 person-years. Expect a 6 times larger incidence in later screening as the population ages. As of September 2013 the observed prevalence of thyroid cancer in Fukushima is 0.031%. It will be important to use standard approaches for realistic dose reconstruction and analytical epidemiological studies. Maternal radioiodine exposure is the pathway for thyroid dose to the fetus. Fetal thyroid dose is largest in the third trimester of pregnancy.

6 The International Workshop on Radiation and Thyroid Cancer(Day 2 ) Dose EstimationEffects Identification Dose Response Relationship Risk Estimation


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