A comparison of neutron beams for BNCT based on in-phantom neutron field assessment parameters

In this paper our in-phantom neutron field assessment parameters, T and D-T umor, were used to evaluate several neutron sources for use in BNCT. Specif ically, neutron fields from The Ohio State University (OSU) Accelerator-Bas ed Neutron Source (ABNS) design, two alternative ABNS designs from the lite rature (the Al/AlF3-Al2O3 ABNS and the (LiF)-Li-7-Al2O3 ABNS), a fission-co nvertor plate concept based on the 500-kW OSU Research Reactor (OSURR), and the Brookhaven Medical Research Reactor (BMRR) facility were evaluated. In order to facilitate a comparison of the various neutron fields, values of T and D-Tumor were calculated in a 14 cmX14 cmX14 cm lucite cube phantom lo cated in the treatment port of each neutron source. All of the other releva nt factors, such as phantom materials, kerma factors, and treatment paramet ers, were kept the same. The treatment times for the OSURR, the (LiF)-Li-7- Al2O3 ABNS operating at a beam current of 10 mA, and the BMRR were calculat ed to be comparable and acceptable, with a treatment time per fraction of a pproximately 25 min for a four fraction treatment scheme. The treatment tim e per fraction for the OSU ABNS and the Al/AlF3-Al2O3 ABNS can be reduced t o below 30 min per fraction for four fractions, if the proton beam current is made greater than approximately 20 mA. DTumor was calculated along the b eam centerline for tumor depths in the phantom ranging from 0 to 14 cm. For tumor depths ranging from 0 to approximately 1.5 cm, the value of D-Tumor for the OSURR is largest, while for tumor depths ranging from 1.5 to approx imately 14 cm, the value of D-Tumor for the OSU-ABNS is the largest. (C) 20 01 American Association of Physicists in Medicine.