Table 1.

Cell survival parameters of T/C-28a2 cells (fitted from curves of Fig. 2a)

	D10a	D37b	SF2c	RBE (D10)d	RBE (D37)e
X-Rays 225 KV	5.60	3.47	0,67	/	/
C-ions 28 keV/μm	2,25	0.97	0,12	2.49	3.58

^a The D10 dose gives a surviving fraction of 0.1

^b The D37 dose gives a surviving fraction of 0.37

^c The SF2 fraction is observed at a 2Gy irradiation

^d RBE (D10) values are calculated as (D10 X-Rays) / (D10 C-ions)

^e RBE (D37) values are calculated as (D37 X-Rays) / (D37 C-ions)

X-Rays irradiation: Linear-quadratic model

SF(Dose) = exp. (Alpha*Dose + Beta*Dose^2)

SF(0) = −0,1812

Alpha = −0,0831

Beta = −0,0583

Alpha/Beta - ratio = 14,249

C-ions irradiation: Linear model:

SF(Dose) = exp. (a*Dose)

SF(0) = 0,2998

a = −10,212