摘要:Evidence to date from a number of studies, indicates that there is an increased incidence of thyroid cancer among A-bomb survivors, and that the incidence rises with increase of dose and is especially predominant in females exposed at younger ages. Although 45 years have elapsed since A-bomb exposure, there are still some questions about the development of thyroid cancer: 1) Is the incidence now decreasing? 2) What factors, other than radiation exposure, are involved? 3) What is the incidence of multiple cancer, including thyroid cancer? With these questions in mind, it is apparent that studies in this field must continue for some time to come.