Earticle

초록

영어

Background: This study examined the detection limit of thyroid screening monitoring conducted at the time of the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011 using a Monte Carlo simulation. Materials and Methods: We calculated the detection limit of a NaI(Tl) survey meter to measure 131I accumulation in the thyroid gland of children. Mathematical phantoms of 1- and 5-year-old children were developed in the simulation of the Particle and Heavy Ion Transport code System code. Contamination of the body surface with eight radionuclides found after the FDNPP accident was assumed to have been deposited on the neck and shoulder area. Results and Discussion: The detection limit was calculated as a function of ambient dose rate. In the case of 40 Bq/cm2 contamination on the body surface of the neck, the present simulations showed that residual thyroid radioactivity corresponding to thyroid dose of 100 mSv can be detected within 21 days after intake at the ambient dose rate of 0.2 μSv/hr and within 11 days in the case of 2.0 μSv/hr. When a time constant of 10 seconds was used at the dose rate of 0.2 μSv/hr, the estimated survey meter output error was 5%. Evaluation of the effect of individual differences in the location of the thyroid gland confirmed that the measured value would decrease by approximately 6% for a height difference of ±1 cm and increase by approximately 65% for a depth of 1 cm. Conclusion: In the event of a nuclear disaster, simple measurements carried out using a NaI(Tl) scintillation survey meter remain effective for assessing 131I intake. However, it should be noted that the presence of short-half-life radioactive materials on the body surface affects the detection limit.

목차

ABSTRACT
Introduction
Materials and Methods
Results and Discussion
1. Survey Meter Reading Errors
2. 1 cm Dose Equivalent Rate from Contamination of the Cervical Body Surface
3. Detection Limit in the Case of Neck Contamination
4. Effects of Ambient Dose Rates on the Detection Limits
5. General Consideration of Thyroid Measurement
6. Effects of Cervical and Shoulder/Chest Contamination
7. Effects of Short-Lived Nuclides
8. Effects of Short-Lived Nuclides on Thyroid Doses
9. Effects of Thyroid Depth and Height Due to Differences in Body Shape
Conclusion
Conflict of Interest
Acknowledgements
Ethical Statement
Author Contribution
References

키워드

저자

• Takahiro Kitajima [ Nippon Bunri University Medical College, Oita City, Japan; Oita University Graduate School of Nursing and Health Sciences, Oita City, Japan; ] Corresponding Author
• Michiaki Kai [ Department of Health Sciences, Nippon Bunri University, Oita City, Japan ]

참고문헌

발행기관

간행물

표지보기 관심저널 등록

• 간행물명

  방사선방어학회지 [Journal of Radiation Protection and Research]

• 간기

  계간

• pISSN

  2508-1888

• 수록기간

  1976~2026

• 등재여부

  KCI 등재,SCOPUS

• 십진분류

  KDC 559 DDC 629