Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, Maryland 20892-7238, USA.
Clin Oncol (R Coll Radiol). 2011 May;23(4):244-50. doi: 10.1016/j.clon.2011.01.159. Epub 2011 Feb 5.
In 2008, the worldwide estimated age-standardised incidence rates for thyroid cancer incidence were 4.7 and 1.5 per 100,000 women and men, respectively. Thyroid cancer's overall contribution to the worldwide cancer burden is relatively small, but incidence rates have increased over the last three decades throughout the world. This trend has been hypothesised to reflect a combination of technological advances enabling increased detection, but also changes in environmental factors, including population exposure to ionising radiation from fallout, diagnostic tests and treatment for benign and malignant conditions. Studies of the atomic bomb survivors and populations treated with radiotherapy have established radiation as a risk factor for thyroid cancer, particularly from early life exposure. About 0.62 mSv (20%) of the global annual per caput effective radiation dose comes from diagnostic medical and dental radiation for the period of 1997-2007, increased from 0.4 mSv for the years 1991-1996. This international trend of increasing population exposure to medical diagnostic sources of radiation, attributed in large part to the growing use of computed tomography scans, but also interventional radiology procedures, has raised concerns about exposure to radiosensitive organs such as the thyroid. Worldwide, medical and dental X-rays constitute the most common type of diagnostic medical exposures, but their contribution to the cumulative effective dose is relatively low, whereas computed tomography scans account for 7.9% of diagnostic radiology examinations but 47% of the collective effective dose from diagnostic radiation procedures in parts of the world. Although the radiation exposure from computed tomography scans is substantially lower than that from radiotherapy, multiple computed tomography scans could result in non-trivial cumulative doses to the thyroid. Studies are currently underway to assess the incidence of cancer in large cohorts of children who received computed tomography scans. National and international efforts have been developed to raise awareness and to standardise procedures for use of computed tomography and interventional radiology procedures in paediatric and general populations.
2008 年，全球估计甲状腺癌发病率的年龄标准化发病率分别为女性和男性每 10 万人 4.7 和 1.5 例。甲状腺癌在全球癌症负担中的总体贡献相对较小，但在过去三十年中，全球发病率一直在上升。这种趋势被假设反映了技术进步使检测增加的结合，但也反映了环境因素的变化，包括人口接触放射性沉降物、诊断测试和良性及恶性疾病的治疗所产生的电离辐射。对原子弹幸存者和接受放射治疗的人群的研究已经确定了辐射是甲状腺癌的一个风险因素，特别是来自早期生活的暴露。在 1997-2007 年期间，全球每年人均有效辐射剂量的 0.62 毫希弗（20%）来自诊断性医疗和牙科辐射，比 1991-1996 年的 0.4 毫希弗有所增加。这种全球人口对医疗诊断辐射源暴露增加的国际趋势，在很大程度上归因于计算机断层扫描的广泛使用，但也归因于介入放射学程序，这引起了对甲状腺等对辐射敏感的器官的暴露的关注。在全球范围内，医疗和牙科 X 射线是最常见的诊断性医疗照射类型，但它们对累积有效剂量的贡献相对较低，而计算机断层扫描占诊断放射学检查的 7.9%，但占世界部分地区诊断性放射程序的总有效剂量的 47%。尽管计算机断层扫描的辐射暴露明显低于放射治疗，但多次计算机断层扫描可能导致甲状腺的非微不足道的累积剂量。目前正在进行研究，以评估接受计算机断层扫描的大量儿童癌症发病率。已经制定了国家和国际努力，以提高认识并标准化儿童和普通人群中使用计算机断层扫描和介入放射学程序的程序。
