18F-fluoro-ethyl-tyrosine (18F-FET) PET/CT as a potential new diagnostic tool in multiple myeloma: a preliminary study

Aim of the study: The aim of this study was to analyse the diagnostic accuracy of "18F-fluoro-ethyl-tyrosine (18F-FET) PET/CT tracer in multiple myeloma. Material and methods: The analysed group included: patients with newly diagnosed active myeloma (eight patients); in very good partial remission or complete remission (VGPR or CR) after treatment (nine patients); and with active disease after relapse (15 patients). Results: In patients with newly diagnosed myeloma, 64 lesions were found using CT and 83 lesions using 18F-FET. In six patients, the number of lesions using CT and 18F-FET was the same, and two had more lesions with the 18F-FET than with the CT. Patients in VGPR or CR had no FET-positive lesions. Fourteen out of 15 patients with active relapsed myeloma had 47 FET-positive lesions, CT assessment of the same group showed 282 lesions. In one patient with relapse soft tissue mass was found with 18F-FET but not with CT. Conclusions: 18F-FET can be a promising alternative to 18F-FDG PET/CT for myeloma-related bone disease diagnosis.