The gamma-ray dose in carcinoma of the thyroid treated by radio-iodine

Abstract

The irregular distribution of radioactive I taken up by carcinoma of the thyroid, and the short range of the beta-rays emitted by I131, appear likely to leave certain regions of the tumors virtually unirradiated by these rays. The dose of radiation in such regions due to the gamma-rays from I131 was measured in operation specimens from 2 cases, and was found to be of the same order of magnitude as the dose calculated for uniform distribution of the radioactivity. Malignant cells were present in some of the regions of low activity. In general it may be impossible to give large enough gamma-ray doses by means of I131 to effect a cure. Other radioactive isotopes of I may prove more useful in the treatment of carcinoma of the thyroid.