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

OBJECTIVE

Radioiodine 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.

METHODS

In 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.

RESULTS

A 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.

CONCLUSION

SPECT/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.