Current Status and Radiobiological Studies Using SPICE-NIRS Microbeam Irradiation System

Microbeams made possible to deliver a defined number of charged particles on a single cell with a resolution of a few micrometers, and are most advantageous for the field of radiation-induced nontargeted effects, so-called bystander effects that are considered to be one of the major effects in the low-dose region. Thus, microbeam technique is advantageous for investigating studies related to addition effect and risk of low dose in space radiation for astronauts and cosmonauts. Our microbeam irradiation system, the Single-Particle Irradiation system to CEll (SPICE) provides a 3.4 MeV proton microbeam focused with a quadrupole magnetic lens on an upward vertical beam line. At present, SPICE is the only proton microbeam facility in Japan at which a single ion single-cell irradiation can be performed on mammalian cells with stability and high throughput using an upward vertical beam of below 2-micrometer in diameter, focused with a magnetic quadrupole triplet lens. A variety of irradiation modes have been established for radiation-induced bystander effects, cytoplasm irradiation etc. Within this several years, we have focused on the radio-induced bystander effects, especially on the aspect on the damaging and protective bystander response and signaling between two different kinds of cells, such as 1) human lung cancer and normal cells, and 2) cancer stem-like cells, CSCsand non stem-like cancer cells, NSCCs in human fibro-sarcoma HT1080 cells. We also expanded our studies to bystander effect in vivo using Zebrafish embryos for bystander effect induced adaptive response. Results on these topics will be also introduced in the presentation. SPICE has been administrated as a ’Joint-use facility for Collaborative Research’, and thus NIRS are accepting research proposal from researchers outside NIRS.International Congress of Radiation Research 201