A COMPARATIVE-STUDY OF TC-99M SESTAMIBI AND TC-99M TETROFOSMIN SINGLE-PHOTON TOMOGRAPHY IN THE DETECTION OF NASOPHARYNGEAL CARCINOMA

The intention of this prospective study was to compare the diagnostic potential of technetium-99m sestamibi (MIBI) and a novel radiotracer, Tc-99m-Tetrofosmin (Tetro), for the assessment of primary nasopharynge al carcinoma (NPC) and the differentiation of residual disease from po st-therapy changes, A total of 38 patients underwent MIBI and Tetro si ngle-photon emission tomography (SPET) imaging at initial presentation (n = 22) or following therapy (n = 16), The findings were correlated with computed tomography or magnetic resonance imaging (MRI) on a site -by-site basis, Tumour/background (Tm/Bkg) ratios were obtained on cor onal sections, Biopsy (nine patients) and/or 12- to 24-month clinical follow-up data were available in the post-therapy group, All primary d isease sites were accurately detected by both imaging studies, Althoug h there was no statistical difference between the two imaging techniqu es in the detection of primary disease, MIBI was superior to Tetro in the detection of regional lymph node metastases (sensitivity: 95% vs 7 9%). Tetro and MIBI SPET were true-positive in all patients (n = 7) wi th proven residual/recurrent disease, In nine patients who had no evid ence of residual/recurrent tumour, MRI was false-positive in five whil e Tetro and MIBI SPET were false-positive in two and three patients, r espectively. Tm/Bkg ratios were less than or equal to 1.7 in all false -positive cases except one, Tetro, MIBI and MRI had specificities of 7 8%, 67% and 44%, and accuracies of 87.5%, 81% and 69%, respectively, T he results of Tetro and of MIBI SPET were not statistically different from one another with regard to the prediction of residual/recurrent o r metastatic NPC.