Paired miniature tissue-equivalent proportional counters for dosimetry in high flux epithermal neutron capture therapy beams

Boron neutron capture therapy (BNCT) is a promising alternative to conventi onal radiation therapy for highly malignant brain tumors. Due to the variet y of types of radiation present, and the short range of some of these parti cles, accurate dosimetry for BNCT is very difficult. Low pressure tissue eq uivalent proportional counters (TEPCs) are able to provide detailed informa tion about the radiation types as well as microdosimetric information by pr oviding the complete single event spectrum of charged particles depositing the dose in a simulated microscopic site. TEPC microdosimetry for BNCT has thus far been limited by the large size of commercially available TEPCs. To overcome this problem, a pair of miniature TEPCs has been constructed with sensitive volumes of 0.0027 cm(3). Design considerations for these counter s as well as preliminary absorbed dose measurements are presented. (C) 1999 Elsevier Science B.V. All rights reserved.