Online ISSN : 1884-4111
Print ISSN : 0033-8303
ISSN-L : 0033-8303
Section 8 [Radiation Biology] Contribution of HIMAC for Radiation Biology
8.2.4 Oxygen Effect in the High LET Region
Atsushi ItoRyoichi Hirayama
Author information

2019 Volume 68 Issue 10 Pages 709-714


High LET radiation is highly expected to control hypoxic fraction in tumor tissue that shows radiation resistance to low LET radiation, because oxygen effect decreases with increasing LET. Due to the availability of various ions and LETs, HIMAC has produced many outcomes from basic to clinical studies. In the basic studies, the mechanism of decreasing oxygen effect with increasing LET was experimentally examined based on the previously proposed “oxygen in the track” model. In addition, in vitro cellular and in vivo transplanted tumor studies demonstrated the LET dependent feature of DNA damage produced under hypoxic condition. For the effort to connect basic studies to clinical trials, measurement of LET dependence of OER (Oxygen Enhancement Ratio) was extended to various oxygen concentrations to mimic oxygen environment in tumors. Finally clinical research using carbon ions for cervical cancer patients demonstrated the effective control of hypoxic fraction.

Information related to the author
© 2019 Japan Radioisotope Association
Previous article Next article