B-10-editing H-1-detection and F-19 MRI strategies to optimize boron neutron capture therapy

Boron neutron capture therapy (BNCT) is a binary radiation therapy used to treat malignant brain tumors. It is based on the nuclear reaction (B-10 + n(th) -> [B-11*]-> alpha + Li-7 + 2.79 MeV) that occurs when B-10 captures a thermal neutron to yield alpha particles and recoiling Li-7 nuclei, both responsible of tumour cells destruction by short range and high ionization energy release. The clinical success of the therapy depends on the Selective accumulation of the B-10 carriers in the tumour and on the high thermal neutron capture cross-section of B-10. Magnetic resonance imaging (MRI) methods provide the possibility of monitoring, through B-10 nuclei, the metabolic and physiological processes suitable to optimize the BNCT procedure. In this study, spatial distribution mapping of borocaptate (BSH) and 4-boronophenylalanine (BPA), the two boron carriers used in clinical trials, has been obtained. The BSH map in excised rat brain and the F-19-BPA image in vivo rat brain, representative of BPA spatial distribution, were reported. The BSH image was obtained by means of double resonance B-10-editing H-1-detection sequence, named M-Bend, exploiting the J-coupling interaction between B-10 and H-1 nuclei. Conversely, the BPA map was obtained by F-19-BPA using F-19-MRI. Both images were obtained Lit 7 T, in C6 glioma-bearing rat brain. Our results demonstrate the powerful of non conventional MRI techniques to optimize the BNCT procedure. (C) 2008 Elsevier Inc. All rights reserved.