Use of volume derived from three-dimensional computed tomography to follow-up a retrosternal compressive toxic multinodular goiter treated with I-131

The standard therapy for multinodular gaiter (MNG) has been surgery. Recent ly, there have been several reports of radioiodine (I-131) being used succe ssfully as treatment. In this report, we describe a case of a large, compre ssive, retrosternal-toxic MNG (thyroid volume 217 cc) that was treated with I-131 with a dose of 105 mCi (88 mu Ci/g of thyroid tissue) with good resp onse. Thy raid function tests normalized posttreatment, and the thyroid vol ume diminished to 125 cc by 6 months and 108 cc at 1 year (50% reduction in size). The volume of the thyroid was determined by spiral computed tomogra phy of the neck with 3D assessment, using planimetry.