International Conference

It is necessary to accumulate the B atoms selectively to the tumor cells for effective boron neutron capture therapy (BNCT). In order to achieve accurate measurements of B concentrations in biological samples, we employ a technique of neutron capture autoradiography (NCAR) of the sliced whole body samples of tumor bearing mice using CR39 plastic track detectors. The CR-39 detectors attached with samples were exposed to thermal neutrons in the thermal column of the TRIGA II reactor at the Institute for Atomic Energy, Rikkyo University. We obtained NCAR images for mice injected intraveneously by B-polyethylene-glycol (PEG) binding liposome or B-bare liposome. The B concentrations in the tumor tissue of mice were estimated by means of alpha and lithium track density measurements. In this study, we increased the accumulation of B atoms in the tumor tissues by binding PEG chains to the surface of liposome, which increase the retension in the blood flow and escape the phagocytosis by reticulo-endotherial systems. Therefore, B-PEG liposome is a candidate for an effective B carrier in BNCT .