猎人说的是否是，在临床上外源性辐射是不被算作致甲状腺癌的原因？
但是，斑竹和猎人引用那个书还是Paper好像是说外源性的辐射是可以造成甲状腺癌啊。我用Google搜了一下，除了Google Book上有不全的preview，那个文章还有个PDF可以看。
我下载了,看了两眼，胡说两句。（我既不是学医的也不是学生物，统计，物理等等的 。。。 理解错误，用词错误，在所难免，请多包涵，如果有临床专业人士能指明解惑当然更好。）
文章的名字是:"Epidemiology and Etiology of Thyroid Nodules and Thyroid Cancers."
据我理解，文章最后一段："Summary and Key Facts" 说得清清楚楚，外源性辐射是甲状腺癌的致癌原因之一 （radiation as an etiologic factor ...The radiation is usually external ... ）。同时切尔诺贝利事件中内源性辐射也会让孩子得甲状腺癌。
Most thyroid cancers are sporadic and no single cause can be identified. A proportion of thyroid cancers are associated with radiation as an etiologic factor and a proportion have a genetic link. The radiation is usually external and there is a linear relationship from about 0.05–0.1 Gy (50–100 mGy or 5–10 rad) to 5–10 Gy (500–1000 rad). There is an excess risk ×7.7 per Gy. Children exposed to internal radiation resulting from the accident at Chernobyl also have a definite increase in the incidence of thyroid cancer. Genetic defects in
the RET protooncogene are the cause of 25%–30% of medullary cancers and 100% of the MEN 2A and 2B syndromes.
还有至于现在放射医疗工作者得甲状腺癌比例和正常人群一样，文章是这么说的：
Medical Occupational Exposure
I am aware of colleagues in nuclear medicine and radiologic specialties who have had thyroid cancer but the denominator is unknown. Cancer mortality in radiologists who worked in the UK between 1897 and 1997 showed no increase in specialists registered after 1954. There was an increase in earlier years but radiation safety precautions were less rigorous at that time. In a different study, cancer mortality was studied in 146,000 radiology technologists.There were 7 deaths from thyroid cancer, 6 in women, and this was the exact number expected in the general population. In summary, the published data show no increase in thyroid cancer deaths in medical personnel who work with radiation.
这段话里有一句是这么说的，“There was an increase in earlier years but radiation safety precautions were less rigorous at that time.”可见在过去，辐射安全措施不严格的时候，和辐射接触的医疗人员得癌（包括甲状腺癌？）的比例还是有过增加的。不过现在，因为安全措施完善，不会对医疗人员造成伤害。这是否是更说明了工作环境安全措施的重要性？
2011年的NY Times 有一篇文章“No Need to Panic About X-Rays and Thyroid Cancer”
http://www.nytimes.com/2011/04/26/health/26brody.html?_r=0是提到了被诊断出得了甲状腺癌的人在近年大量增加，但是人口中死于甲状腺癌的人的比例并没有变，说明很多被诊断出来的人就是不治也无妨。
¶Diagnoses of thyroid cancer have increased sharply in recent decades. Between 1980 and 2007, the incidence rose to 17 per 100,000 from 6 per 100,000 each year, and to 5.8 per 100,000 from 2.5 per 100,000 men each year. The number of diagnoses in women nearly doubled from 2000 to 2008.
¶Yet the death rate from this disease has not increased, and more than 97 percent of patients survive.
Dr. Otis W. Brawley, chief medical officer of the American Cancer Society, said the stable death rate despite a rising incidence strongly suggests that most of the thyroid cancers now being diagnosed would never have become a health threat.
“Our technology has gotten so good that we are finding cancers today that even 15 years ago would not have been diagnosed,” Dr. Brawley said in an interview. “We’re finding and treating cancers that would never have killed anyone.”