TY - JOUR T1 - Trabecular bone changes induced by fast neutrons versus gamma rays in mice TT - JF - Int-J-Radiat-Res JO - Int-J-Radiat-Res VL - 13 IS - 3 UR - http://ijrr.com/article-1-1520-en.html Y1 - 2015 SP - 251 EP - 257 KW - Neutrons KW - trabecular bone KW - osteoclast KW - relative biological effectiveness N2 - Background: The trabecular bone changes in the tibia of C3H/HeN mice were measured 12 weeks after whole body irradiation with various doses of fast neutrons (0-2.4 Gy) or 137Cs-generated gamma-rays (0-6 Gy). Materials and Methods: Serum calcium, phosphorus, estradiol concentration and alkaline phosphatase activity were measured. Tibiae were analyzed using microcomputed tomography. Biomechanical property and osteoclast surface level were measured. Results: There was a significant relationship between the loss of bone architecture and the radiation dose, and the best-fitting dose-response curves were linear-quadratic. Mean relative biological effectiveness (RBE) values (Ref. gamma) of 2.05 and 2.33 were estimated for fast neutron irradiation in trabecular bone volume fraction and bone mineral density, respectively. There was a substantial reduction in osteoclast surface level in tartrate-resistant acid phosphatase-stained histological sections of tibial metaphyses in irradiated mice with high dose of neutrons. Conclusion: There was a significant relationship between the loss of bone architecture and the radiation dose. The difference of osteoclastic bone resorption may represent a contributor to the low RBE in high dose of irradiation level relative to that of low dose level. M3 10.7508/ijrr.2015.03.008 ER -