Retention of Iodine-131 in Respiratory Tract in a Patient with Papillary Thyroid Carcinoma After Radionuclide Therapy: A Rare False-Positive Finding

Abstract

F ALSE-POSITIVE 131 I whole-body scan (WBS) findings mimicking metastases of differentiated thyroid carcinoma have long been reported. We now report a case of falsepositive 131 I scan in a 62-year-old female who underwent radioiodine treatment after surgery for lung metastasis of papillary thyroid cancer. Three days after therapeutic administration of 5550 MBq 131 I a WBS was performed. While WBS revealed no 131 I accumulation in the lung, a focal retention was observed in the mid-thorax. A further anatomic clarification of this uptake has been undertaken with the novel x-ray-CT/SPECT technology in a single device (Millenium VG with Hawkeye, GE Medical Systems, Milwaukee, WI). The transmission/emission tomography of the thorax demonstrated the 131 I uptake being in the tracheobronchial region (Fig. 1). After detailed exploration this unusual accumulation is thought to be caused by the use of local aerosol *If you would like to submit an image for publication in "Images in Thyroidology," please send two copies of high-quality black-andwhite images with a short legend. In special circumstances color figures will be published. Please inquire for details from the Section Editor. All material must be original and neither published nor submitted elsewhere. The legend should give relevant clinical information. The entire legend should be typed double-spaced, and should be no more than 200 words. Send all submissions to Yaron Tomer, M.D.,

Incremental Value of 131I SPECT/CT in the Management of Patients with Differentiated Thyroid Carcinoma

“…At the same time, Ruf et al performed a prospective study and concluded that the addition of SPECT/CT improved the interpretation of inconclusive 131 I findings on planar scans after ablative radiotherapy (23). In addition, the role of 131 I SPECT/CT in DTC patients has been described in a few case reports, including detection of benign struma ovarii in a patient with invasive papillary thyroid cancer (24), renal metastases from follicular thyroid cancer (25), and retained radioiodine in the respiratory tract of a patient with papillary thyroid carcinoma (26). In our series, the hybrid imaging device provided a significant contribution in up to 73.9% of patients whose 131 I WBS findings were inconclusive, thus having a substantial impact on the clinical management of DTC patients referred for radioiodine therapy.…”

Esophageal 99mTc-pertechnetate uptake mimicking an autonomous thyroid adenoma in a patient with subacute thyroiditis: a case report

“…Tracheal uptake was reported with the use of aerosol drugs. [ 8 ] Our patient was not using any local aerosol, making it unlikely that the observed hot focus was located in the trachea.…”