FALSE POSITIVE RADIOIODINE POST-ABLATION SCAN IN SCALP REGION IN A WOMAN WHO USED HAIR COLORING REVEALED BY SPECT/CT

OBJECTIVERadioiodine ablation with iodine-131 is a standard therapeutic procedure for patients diagnosed with differentiated thyroid carcinoma (DTC). We present a contamination artifact on whole-body scan (WBS), after radioiodine ablation due to papillary thyroid carcinoma. The hybrid imaging resolved the question of metastasis versus contamination. METHODSIn the case of 35-year-old female patient we used a General Electric hybrid gamma camera with a high-energy-general-purpose collimator for performing WBS, and single photon emission computed tomography combined with low dose computed tomography (SPECT/CT) for the detection of any residual thyroid tissue or meta-static disease and at the same time ablation and treatment of any confirmed metastasis. RESULTSA thyroid scan showed activity in the remnant thyroid tissue of the right lobe, but also laterally in the calvaria (left temporal region). The patient's neck ultra-sound and thyroglobulin level were not in favor of metastasis. A false positive finding due to hair coloring was concluded with SPECT/CT hybrid imaging. CONCLUSIONSPECT/CT scan can contribute to establishing a final diagnosis in patients being evaluated for atypical locations of radioactive iodine accumulation after ablative doses of radioactive iodine, distinguishing between metastases from DTC and false positive accumulations or artifacts.