[The influence of the galenic form of 131I administration on the results of radioiodine tests--comparison of 131I in capsules and in solutions (author's transl)].

A comparative study of thyroid uptake and PB131I in two groups of 20 euthyroid persons each was performed. In one group 131I was administered in the form of capsules and in the other as a solution. The application of 131I in capsule form showed no significant decrease of thyroid uptake at 2, 24 and 48 hr but a significant diminishment of PB131I 48 hr after capsule ingestion (p less than 0,05). In 3 patients the scintiscans of the abdomen 24 hr after administration of three 131I capsules (90 muCi) revealed no circumscribed areas of activity. Because the iodine metabolism is dependent upon the kind of carrier, we conclude that for thyroid uptake measurements and the following 131I therapy the same 131I preparation should be used.