Iodomethyl - = - Tyrosine Be a Surrogate for Bpa in Bnct ?

INTRODUCTION A single-photon emission computed tomography [SPEW imaging agent that analogue of a boron carrier for boron neutron-capture therapy VNCT] of cerebral gli be useful for assessing the kinetics of boron uptake in tumors and in the surrounding noninvasively. BNCT is based on the interaction of thermalized neutrons with 10B nuclei in the targeted tumor. For B N m of brain tumors, it is crucial that *OB concentrations in radiosensitive regions of the brain be minimal since malignant cells and vital brain tissues are often intermingled at the margins of the tumor. C m n t l y , boronophenylalanine @3PA]-mediated Z3NCT is undergoing preiiminary clinical study for postoperative radiotherapy of glioblastoma muitiforme at Brookhaven National Laboratory [l]. Investigators in Japan are developing 1 *F-fluoroboronophenylalanine P P A ] as a positron emission tomography eE3] surrogate for BPA [Z]. 18F (T1/2 = 110 min), which is usually generated at a cyclotron dedicated to PET, is generally a minimally perturbing substitute for the 2H on the aromatic ring because of its small size and the strong covalent bond it forms with carbon. However, SPECT has potential advantages over PJ3: 1) SPECT is clinically more widely available at lower cost; 2) most radioisotopes for the synthesis of SPECT agents can be purchased; 3) SPECI' is less difficult to implement. It is thought that the quality of images derived from the two techniques would each be sufficiently informative for BNCT treatment planning purposes, provided that the SPECT and PET agents being considered were both pharmacokinetic surrogates , for BPA.