Tomographic Imaging of the Human Thyroid Using¹²⁴I∗

Abstract

After receiving between 100 and 300 mu Ci of the positron-emitting radioisotope 124I (half-life, 4.2 days), 64 patients with a variety of thyroid disorders were imaged with a high resolution positron camera. A 3-dimensional image of the distribution of radioiodine uptake within the thyroid was obtained from a single 10- to 15-min scan. This image may be viewed as a sequence of 2-mm thick transverse, sagittal, or frontal sections or as a 3-dimensional shaded surface. The functional volume of the thyroid may be estimated by counting the volume elements (voxels) inside the thyroid surface. The precision of the estimate varied from 6-15%, depending on the size and clinical status of the thyroid. The volume estimation procedure was validated with phantoms and with the thyroids of patients who subsequently underwent partial thyroidectomy. This 3-dimensional imaging technique may be useful for diagnosis and management of thyroid diseases.

Combined PET/CT with iodine-124 in diagnosis of spread metastatic thyroid carcinoma: a case report

“…Furthermore, the additional morphologic information showed iodine-negative and FDG-positive metastasis in the thoracic vertebrae; hence, systematic evaluation of iodine-124 PET/CT in staging of DTC in clinical studies appears to be mandatory. Moreover, a further advantage of iodine-124 PET in the management of DTC lies in exact dosimetry for iodine-131 therapy [12,13,14,15,16,17,18,19]. By combining anatomical information and activity concentration of iodine-124 PET/CT has the potential to further improve dosimetry.…”

“…Because of a complex decay scheme including several high-energy gamma rays [12,13,14,15,16,17,18,19], iodine-124 is not appropriate for imaging with a gamma camera and PET scanners have only recently become more widely available. Although PET is a superior imaging system with physical advantages compared with planar cameras and single photon emission computed tomography (SPECT), it has not been established for imaging thyroid cancer with iodine.…”

Higher Frequency of Thyroid Tumors in the Right Lobe

“…Various techniques have been used for thyroid volume determination, including palpation (a highly imprecise method) [1][2][3][4][5], various nuclear medicine and radiological techniques such as planar 99m Tc-scintigraphy [6], positron emission computed tomography [7,8] or single photon emission tomography [9], computed tomography (CT) [10,11], and magnetic resonance imaging [12]. Because of lack of precision, cost, radiation exposure, and/or time needed, these are hardly used nowadays.…”

Value of 124I-PET/CT in staging of patients with differentiated thyroid cancer

“…Iodine-124, an isotope with a half-life of 4.2 days, is suitable for PET imaging and has already been used for dosimetry [7][8][9][10][11][12][13]. Although PET is a superior imaging system with physical advantages compared to planar gamma cameras and SPECT, it has not been established for routine imaging of thyroid cancer with iodine for several reasons: first, because of the complex decay scheme of 124 I that includes several high-energy gamma rays and makes 124 I imaging a challenge for a gamma camera.…”