Scintigraphic estimation of thyroid volume and dose distribution at treatment with 131I.

A scintigraphic method for estimation of thyroid volume and dose distribution for 131I in the thyroid gland is presented using a gamma camera with pinhole collimator connected to a minicomputer and digital system. The three dimensions of each lobe are measured and the volume calculated using the ellipsoid model. Problems regarding changes in magnification and sensitivity with object to collimator distance have been investigated. The iodine distribution in the thyroid gland has been followed for 72 hours after oral administration of 131I in 25 cases. No significant change in distribution was observed in any of the cases.