Ja. Coderre et al., The effects of boron neutron capture irradiation on oral mucosa: evaluation using a rat tongue model, RADIAT RES, 152(2), 1999, pp. 113-118
The ventral surface of the tongue of male Fisher 344 rats was used to evalu
ate the response of oral mucosa to boron neutron capture irradiation. Three
hours after i.p. injection of 700 mg/kg of the boron delivery agent p-boro
nophenylalanine (BPA), the boron concentrations in blood and tongue mucosal
epithelium were approximately 21 and 23 mu g B-10/g, respectively. The dos
es required to produce a 50% incidence of ulceration with X rays, the Brook
haven Medical Research Reactor thermal neutron beam alone, or the thermal n
eutron beam in the presence of BPA were 13.4 +/- 0.2, 4.2 +/- 0.1, and 3.0
+/- 0.1 Gy, respectively. Ulceration of the tongue was evident by 6 to 7 da
ys after irradiation, irrespective of the irradiation modality; healing was
related to dose and was relatively rapid (less than or equal to 19 days).
Compared to 100 kVp X rays, the relative biological effectiveness factors w
ere 3.2 for the thermal neutron beam and 4.9 for the products of the boron
neutron capture reaction, B-10(n,alpha)Li-7. Oral mucosa is highly sensitiv
e to BPA-mediated BNC irradiation and could be a dose-limiting normal tissu
e in BNCT of brain tumors, or if BPA-based BNCT is applied to the treatment
of head and neck tumors. (C) 1999 by Radiation Research Society.