Neutron capture autoradiographic determination of [formula omitted] distributions and concentrations in biological samples for boron neutron capture therapy

Abstract

It is necessary for effective boron neutron capture therapy (BNCT) to accumulate 10 B atoms in the tumor cells. We prepared a cationic liposome entrapped 10 B compound for the delivery system and examined the delivery capacity of 10 B atoms to pancreatic cancer cell, AsPC-1, in vivo. It is required to achieve an accurate measurement of 10 B distributions and concentrations in biological samples with a sensitivity in the ppm range for BNCT. We applied CR-39 (polyallyldiglycol carbonate) plastic track detectors to α-autoradiographic measurements of the 10 B biodistribution in sliced whole-body samples of mice. To selectively desensitize undesirable proton tracks, we applied PEW (KOH+C 2H 5OH+H 2O) solution to the etching of CR-39 detector. The subsequent use of an alpha-track radiographic image analysis system enabled a discrimination between alpha tracks and recoiled proton tracks by the track size selection method. This enabled us to estimate quantitatively the distributions of 10 B concentrations within the tissue sections by comparing with suitable standards.