@misc{oai:repo.qst.go.jp:00067583,
 author = {Furusawa, Yoshiya and Shimao, Daisuke and Matsumoto, Yoshitaka and Aoki, Mizuho and Kubota, Nobuo and Ando, Koichi and 古澤 佳也 and 松本 孔貴 and 青木 瑞穂 and 窪田 宜夫 and 安藤 興一},
 month = {Mar},
 note = {An estimation method of radiobiological effectiveness at very low-survival (or high-dose) region on a malignant melanoma cells was investigated, for a treatment planning of eye melanoma at HIMAC, where high-dose exposure per each fractionation is required. Survival fractions were obtained using X-rays and heavy-ions at LET values among 13 - 300 keV/_m by colony formation methods for single-cells (low-dose region) and multicellular spheroids (high-dose region) of HMV-I cells. The linear-quadratic (LQ) equation and the multi-target single-hit (MS) equation together with a combined (LMS) equation, S = exp(-aD)[1-{1-exp(-D/Do)}n ], obtained from the linear part of the LQ equation and the MS equation were used for survival data fitting.  Survival data obtained from single-cells and spheroids were combined each other.  The LQ equation fits well for the combined survival data at lower dose region or single-cells survival data.  The MS equation fits well combined survival data at higher dose region of spheroid data. The LMS equation fits well for the combined survival data for all dose region tested.  We estimated the RBE values of the ion-beams from low to high dose regions by using the combined survival data with LMS equation.  The RBE values at very high survival level (> 50 %) were ~3.7 at 300 keV/mm or ~1.8 at 13 keV/mm, decreased with survival level quickly at higher (~ 10 %) survival level and converged at very low survival level to be ~1.5 for ion-beams at LET value 13 - 300 keV/_m., The 2nd International Workshop on Space Radiation Research},
 title = {A method to estimate radiobiological effectiveness at a very low surviving level of cells},
 year = {2002}
}