Technetium-99m-MIBI in the follow-up of differentiated thyroid carcinoma

• Autor(a) principal: Machado, Luiz S.
• Data de Publicação: 2004
• Outros Autores: Pedras, Dauro S.V., Antonucci, Jane B., Corbo, Rossana
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Revista Brasileira de Cancerologia (Online)
• Texto Completo: https://rbc.inca.gov.br/index.php/revista/article/view/2024
• topic: Neoplasias da tireóide; Carcinoma; Cintilografia; Tireoglobulina; MIBI; Thyroid neoplasms; Carcinoma; Radionuclide imaging; Thyroglobulin; MIBI

Technetium-99m-methoxyisobutil isonitrila (99mTc-MIBI) has been introduced as a tumor-seeking agent in the past few years. The present study has evaluated the role of 99mTc-MIBI whole body scan (WBS) in localizing metastatic lesions by assessing sensitivity and specificity in comparison with 131I scan and serum thyroglobulin measurement. Eighty-nine thyroidectomized patients due to differentiated thyroid cancer were enrolled. Early (20 minutes) and delayed (6 and 24 hours) whole body images were obtained after 99mTc-MIBI injection. Tg measurements were obtained during thyroid hormone reposition and 4 weeks after hormone discontinuation, 131I scans were performed after low diagnostic or high ablative/therapeutic dose. These methods were used as standard to evaluate the presence of residual or metastatic thyroid cancer. The patients with 99mTc-MIBI scan positive and 131I negative scan underwent chest x-ray, computed tomography (CT) or magnetic resonance imaging (MRI). In the group with 131I negative scan (34/89), 23 patients presented 99mTc-MIBI WBS negative and 11 patients were discordant (specificity: 67,6%), and 22 patients had 99mTc-MIBI WBS and 131I scan positive; while the total of 131I scans positive was 55 (sensitivity: 40,0%). Eleven patients had 131I scan negative and 99mTc-MIBI WBS positive; seven of those proved to be true positive. Although 99mTc-MIBI has low sensitivity on detection of tumor recurrence, it may have a role as a supplementary tool to thyroglobulin measurements and 131I scans.