Molecular imaging for boron neutron capture therapy. ¹⁸F-FBPA-PET, its implications and expectations

¹⁸F-FBPA-PET is investigated as a method for prediction of therapeutic sensitivity of BNCT. Since microdistribution of BPA influences the biological effect of BNCT, if T/B (Tumor/Blood) and N/B (Normal tissue/Blood) ratios are similar in different tumors and normal tissues, the biological effect is not necessarily similar. Therefore, FBPA-PET is just a necessary condition and not a sufficient condition to select a candidate patient for BNCT. However, the usefulness of FBPA-PET can be evaluated by comparing local effect of BNCT in which absorbed dose is calculated by T/B or N/B ratio obtained from FBPA-PET, with the local effect by standard X-ray therapy. In this review, I will explain the implications and expectations of FBPA-PET which can be deduced from the consideration of CBE factor and human tumor radiobiology. (author)