Relationship between the uptake of (18)F-borono-L-phenylalanine and L-[methyl-(11)C] methionine in head and neck tumors and normal organs.

BACKGROUND AND PURPOSE: The purpose of this study was to determine the distribution of 4-borono-2-(18)F-fluoro-phenylalanine ((18)F-BPA) and L-[methyl-(11)C] methionine ((11)C-Met) in normal organs and tumors and to evaluate the usefulness of (11)C-Met/PET in screening potential candidates for boron neutron capture therapy (BNCT).

MATERIAL METHODS: Seven patients who had at least one histologically confirmed head and neck tumor were included in this study. They underwent both whole-body (18)F-BPA-PET/CT and (11)C-Met-PET/CT within a span of 6 months. Uptake was evaluated using the maximum standardized uptake value (SUVmax). Regions of interest (ROIs) were placed within the tumors and target organs of brain, thyroid, submandibular gland, lung, liver, esophagus, stomach pancreas, spleen, muscle, and bone marrow.

RESULTS: The tumor SUVmax of FBPA and (11)C-Met showed strong correlation (r (2) = 0.72, P = 0.015). Although (18)F-BPA and (11)C-Met showed markedly different uptake in some organs (submandibular gland, liver, heart, stomach pancreas, spleen, and bone marrow), the uptake of (11)C-Met was consistently higher than that of (18)F-BPA in these cases.

CONCLUSION: (11)C-Met PET/CT might be used instead of (18)F-BPA PET/CT to predict the accumulation of (10)B in tumors and to select candidates for BNCT. However, it would not be suitable for evaluating accumulation in some normal organs. Therefore, the (18)F-BPA-PET study remains a prerequisite for BNCT. This is the first report of the correlation between (18)F-BPA and (11)C-Met accumulation.