TL-201 SINGLE-PHOTON EMISSION TOMOGRAPHY IN THE TREATMENT FOLLOW-UP OF NASOPHARYNGEAL CARCINOMA

In order to assess the usefulness of thallium-201 single-photon emissi on tomography (SPET) in the treatment follow-up of nasopharyngeal carc inoma (NPC), a total of 75 Tl-201 SPET studies were performed in 18 pa tients with histologically proven NPC. The findings were compared with those of magnetic resonance imaging (MRI) before and after therapy. F our patients received radiotherapy alone while the other 14 received c oncurrent chemo-radiotherapy. Treatment response was classified as com plete (CR) or partial (PR) based on the findings of MRI and Tl-201 SPE T. Intense Tl-201 uptake by the tumour was seen in all 18 patients bef ore treatment. After treatment, MRI showed seven CRs and 11 PRs, where as Tl-201 SPET showed 13 CRs and five PRs. In 12 patients, the results of Tl-201 SPET were in agreement with those of MRI. In six patients M RI showed PR but Tl-201 showed CR. Follow-up (mean 10.6 months) MRI an d Tl-201 SPET studies of these six patients revealed that tumour gradu ally decreased and finally vanished in three patients. This preliminar y study indicates that Tl-201 SPET has potential in the assessment of early response to treatment of patients with NPC when compared with MR I.