¹³¹I Single Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) versus planar gamma-camera imaging in diagnosis of metastasis for intermediate and high-risk patient with thyroid carcinoma

Abstract

Author(s): Rasha Kareem Khagoory, Siham Sabah Abdullah, Mohammed sadoon Al-Shamae Rafid Riyadh Al-Tuma

Background: SPECT/CT is a more effective instrument diagnosing as well as detecting thyroid cancer and determining treatment methods compared to a whole-body planar scan. The objective of this research is to directly compare I31I SPECT/CT methods for detecting metastatic thyroid carcinoma in the high-risk and intermediate-risk group methods to assess the diagnostic precision and performance of iodine-131 body scanning (WBS) with or without SPECT/CT. Patient and Methods: Sixty thyroid carcinoma sufferers, 43 women and 17 men, ages 11 years–76 years had been diagnosed with thyroid malignancy at both the Al-Kawthar Nuclear Medicine Center in Basra and the department of Nuclear Medicine at Al-Andalus Private Hospital in Baghdad. Each patient had a full or almost full thyroid surgery. Patients were divided into two groups: thyroid tumors that have an intermediate-risk and high risk. They were administered dose therapy with radioactive iodine-131 of (3.7 GBq [100 mci]) to (7.4 GBq [200 mci]) and acquired a planar scan 5 days after taking the dose. Planar whole-body examination foci of uptake have been defined as lymph nodes, lung metastases, bone metastases, thyroid remaint, or of unknown cause. These regions were subsequently imaged using a dual-head gamma camera for single-photon emission computed tomography (SPECT/CT), and the categorization was changed according to the imaging. Result: Planar scans depicted 86 foci of 131I activity, classified as 45 neck foci and 41 distal foci. The majority of radioactive iodine uptake foci are located in the lung and bone. These foci were further divided into groups of distant metastasis, metastatic lymph node lesions, physiological activity, and thyroid remnants on SPECT/CT. 4 (7%) of the 39 foci were correctly downgraded from equivocal thyroid remnant to thyroid remnant by SPECT/CT findings, while 16 (27%) of the 39 foci were correctly downgraded from equivocal or thyroid bed remnant. More than two (3%) of the 39 foci were classified as physiological activity or salivary activity. SPECT/CT corrected 2 (3%) of the original 39 foci that were judged to be equivocal in the lymph nodes, and of these, 23 (38%) were correctly identified. The final classification included 2 physiologic activities, 17 metastatic lung lesions, and 11 metastatic bone lesions. However, in cases of bone metastases, additional properties could be achieved with SPECT/CT anatomical localization for iodine activity. Conclusion The present investigation employed SPECT/CT for ultra-fast detection of metastatic tumors with metastatic spread, screening, and efficient verification based on physiological simulation of the disease. Modification of therapeutic strategies in 26 (43%) intermediate-risk patients to high-risk patients of thyroid cancer through precise localization and characterization of iodine-131 avid foci ¹³¹I SPECT/CT shows greater value han ¹³¹I planar Whole-Body (WBS) in treatment management, in addition to being helpful for determining the radioiodine therapy dosage and for directing the surgical procedure.

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