 This is a single BNCT-facility, non-randomized, non-comparative, open-label, phase I to II trial to determine the value of BNCT in the treatment of inoperable, irradiated, locally advanced cancers of the head and neck region. An attempt to perform 18F-labeled boronophenylalanine 18F-BPA SPECT or PET imaging will be made before BNCT. Patients whose tumor uptake is 2.5 times that of the corresponding normal head and neck tissue will be enrolled, and treated with a single fraction BPA-based BNCT twice, 3 to 5 weeks apart. Another 18F-BPA SPECT or PET study may be performed 1 to 3 months after BNCT to determine the SPECTPET response. 