Table 1.

Distribution of survivors according to DS02 colon dose and parameters of the best fit to the Weibull distribution

Dose systema		(a) DS02 colon dose (unmodified)				(b) DS02 colon dose (modified)
City		Hiroshima		Nagasaki		Hiroshima		Nagasaki
Dose category		Mean	Survivor	Mean	Survivor	Mean	Survivor	Mean	Survivor
<0.1		0.017	41 144	0.009	22 190	0.032	21105	0.026	6684
0.1–0.5		0.227	9383	0.246	2079	0.226	9383	0.246	2079
0.5–1.0		0.688	2176	0.738	996	0.661	2200	0.722	996
1.0–1.5		1.256	737	1.260	430	1.180	807	1.195	446
1.5–2.0		1.771	272	1.729	120	1.701	299	1.664	132
2.0–2.5		2.302	241	2.279	74	2.204	316	2.324	101
2.5–3.0b		2.778	31	2.715	24	2.661	22	2.649	65
3.0–3.5		2.273	42	3.173	14
3.5–4.0		3.838	41	3.813	12
4.0–4.5		4.162	46	4.285	17
4.5–5.0		4.784	18	4.694	19
Weibull parameters	μ	10.446 ± 4.424		8.090 ± 4.343		19.314 ± 3.838		32.199 ± 4.571
	κ	0.519 ± 0.199		0.482 ± 0.291		0.643 ± 0.110		0.761 ± 0.077
	Ď	0.212		0.182		0.299		0.404
	$\dot{D}$	0.068		0.046		0.141		0.224

^aDS02 colon doses with neutrons unweighted (RBE = 1): (a) unmodified doses, in which doses are neither truncated nor adjusted. (b) modified doses, in which unreasonably high doses are truncated to 4 Gy and doses are adjusted according to the dose- and city-specific adjustment factors. The number of survivors was compiled from the RERF ‘lssinc07’ database. The surviving probability in Fig. 1 was calculated assuming that the survivors at a given dose category could also tolerate the preceding doses, i.e. S_i = ∑N_i/T, where T is total number of survivors and Ni is the number of survivors at the ith dose category.

^b0.25 ≤ Gy for modified dose system.