Table 1. Average number of nuclei per cell in directly exposed and bystander cells for neutron and cobalt-60 gamma rays.

Radiation dose (Gy)	Nuclear division index
	GM15510 cells		GM15036 cells
	Direct	Bystandea	Direct	Bystandea
Neutrons
0 (pooled)b	2.27	2.11	1.98	2.11
4 (media only)c	-	2.23	-	2.09
0.5	1.61	2.20	1.39	2.00
1	1.46	2.06	1.40	1.98
1.5	1.35	1.90	1.25	2.33
2	1.24	2.18	1.18	1.93
3	1.20d	2.07	1.14d	2.13
4	1.11d	2.30	1.09d	2.14
Cobalt-60 γ
0	1.92	1.79	1.79	1.71
4 (media only)c	-	1.97	-	1.83
0.5	1.87	1.89	1.58	1.79
1	1.64	1.92	1.51	1.93
2	1.24	1.82	1.21	1.81
3	1.13	1.92	1.19	1.82
4	1.06	1.90	1.13	1.85

^aNeutron data shown are for replicate 1; the values for replicate 2 were similar (p>0.05).

^bCombined values of the controls (pre-radiation, post-radiation and transportation control).

^cMedia without cells was irradiated with 4 Gy and transferred to unirradiated cells.

^dToo few high quality binucleated cells were available for scoring.