Abstract
Objective: The nucleoside 3′-deoxy-3′-fluorothymidine (alovudine) is an antiviral agent accumulating in proliferating cells. We prospectively evaluated the biodistribution of the PET tracer [18F]3′-deoxy-3′-fluorothymidine(FLT) and its value in detecting manifestations of non-Hodgkin's lymphoma (NHL). Methods: In this pilot study, 7 patients (6 male, 1 female) with indolent NHL (2), NHL in transformation (2) or aggressive NHL (3) were examined. Patients received initial staging or restaging with an interval of at least 10 weeks between therapy and positron emission tomography (PET). Mean doses of 324 ± 165 MBq FLT were injected intravenously. Static PET scans were performed 50–70 minutes after application. Maximum standardized uptake values (SUV) of organs and NHL manifestations were calculated. FLTpositive lesions were verified by biopsies (3 lesions) or aspiration smears (5 lesions in 4 patients). Results: Biodistribution: The tracer accumulated physiologically in hematopoietic marrow and in the liver. It was renally excreted. SUV of organs 1 hour after injection were: bones with hematopoietic marrow, 9.9 ± 4.7; liver, 5.2 ± 1.0; kidneys, 4.0 ± 1.7; spleen, 3.0 ± 1.2; bones without hematopoietic marrow, 1.9 ± 1.1; lungs, 0.8 ± 0.3. NHL manifestations: In 7 patients, diagnosis was verified as true positive by histology/cytology. Maximum lymphoma SUV of FLT positive lesions were 6 for the indolent group and 8–11 for lymphoma in transformation. In the aggressive group, SUV were 6, 14, and 17. The low SUV in this group was found in a highly proliferate large-cell anaplastic lymphoma combined with marked sclerosis of 30%. Conclusions: In this pilot study, FLT-PET was suitable in the imaging of NHL manifestations. In NHL with normal cellularity, FLT accumulated more intensely in aggressive NHL and NHL in transformation than in indolent NHL. Bones with hematopoietic marrow and the liver were the organs with the highest physiological uptake.
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