ABSTRACT
BNCT is based on the very high cross section of boron-10 nuclei for neutron capture, which is followed by the spontaneous ™ssion of the resulting excited boron-11 nuclei to produce highlinear energy transfer (high-LET) alpha-particles and recoiling lithium-7 nuclei according to the equation:1−4
10B + 1n → 7Li3+ + 4He2+ + γ + 2.4 MeV
The high-LET particles have only limited path lengths in tissue (less than 10 μm) and therefore BNCT has the potential to be highly localized to 10B-containing tumor cells in the presence of normal boron-free cells. However, one of the major challenges in BNCT development has been the discovery of tumor-selective boron agents with the ability to deliver therapeutic boron concentrations (15-30 μg/g tumor) to targeted tumors with minimal normal tissue toxicity.5 The two boron compounds currently used clinically for BNCT of malignant brain tumors, melanomas, and squamous cell carcinomas are the sodium mercaptoundecahydro-closo-dodecaborate (1) designated
10.1 Introduction ..........................................................................................................................209 10.1.1 The Neutron-Capture Reaction ................................................................................209 10.1.2 General Requirements and Strategies....................................................................... 210
10.2 Boron Delivery Agents ......................................................................................................... 211 10.2.1 Derivatives of BSH and Other Boron Clusters ......................................................... 211 10.2.2 Amino Acids and Peptides ....................................................................................... 215 10.2.3 Nucleosides ............................................................................................................... 216 10.2.4 Porphyrin Derivatives ............................................................................................... 219 10.2.5 Other DNA Binders ..................................................................................................226 10.2.6 Antibodies .................................................................................................................228 10.2.7 Liposomes .................................................................................................................230
