Evaluation of Fluoride-18-Labeled Boronophenylalanine-Positron Emission Tomography Imaging for the Assessment of Boron Neutron Capture Therapy in Patients with Recurrent Head and Neck Squamous Cell Carcinoma


Introduction: A role for fluoride-18-labeled boronophenylalanine positron emission tomography (18FBPA-PET) in boron neutron capture therapy (BNCT) has not been fully elucidated. We investigated the role of 18FBPA-PET in BNCT for recurrent head and neck squamous cell carcinoma (HNSCC) patients. Materials and methods: 18FBPA-PET images were obtained from 10 histologically verified recurrent HNSCC patients who received BNCT. The intratumoral accumulation of 18FBPA was calculated as the ratio of maximum and minimum radioactivity counts to that of normal tissue (Tmax/N and Tmin/N ratios, respectively). The percentage volume at which the radioactivity count ratio was >2.5 compared to normal tissue was also calculated (Vo2.5). Moreover, mean and minimum irradiation dose to the tumor was calculated. We investigated which parameters could predict the treatment effect of BNCT. Results: Treatment effects of local lesions were as follows: complete remission (CR) in 5 cases and non-CR in 5 cases. Only Tmin/N ratio showed a significant difference between the CR and non-CR groups (P=0.008). Conclusion: The Tmin/N ratio of 18FBPA-PET can predict the treatment effect of BNCT for recurrent HNSCC.