Revision 1
March 19, 1998
by Radiation, Science, and Health, Inc.,
Edited by J. Muckerheide

1.9
Conclusions

"U.S. National Council on Radiation Protection (NCRP) 121, November 30, 1995 states, ‘ ...essentially no human data can be said to prove or even provide direct support for the concept of collective dose (based on the linear non-threshold "(LNT) theory) with its implicit uncertainties of non-threshold, linearity. and dose-rate independence with respect to risk.’ (NCRP 1995) Efforts to present low-dose data that support the LNT theory, a monotonically increasing risk of cancer, have led to misrepresentation of their data by the authors of three studies: 1) the 1989 Canadian Fluoroscopy Study, (Miller 1989) (2) its 1996 revision in which the 0.10-0.19 Sv and 0.20-0.29 Sv dose groups are missing, (Howe 1996) and 3) the IARC Occupational Workers Study. (Cardis 1995)

"Another effort to support the LNT theory was made in November 1996. The ICRP and the French Society for Radioprotection under Chairman Roger Clarke, reviewed the 1996 RERF Life Span Study of Atomic Bomb Survivors Report 12 which includes the 1985-1990 mortality data. (Pierce 96, Nucleonics Week 1996) The ICRP claimed, though the authors of the Life Span Study did not, that their analysis of this new data showed a statistically significant increased solid cancer mortality at doses as low as 5 rem. According to Warren Sinclair, president emeritus of the NCRP and chairman of the ICRP Committee 1 which analyzes results of health-effects studies, the new results ‘vindicate’ previous recommendations to lower permissible dose limits to 2 rem/year for occupational workers and to 0.1 rem/yr for the general public. ‘The combination of more data points and a more precise analysis,’ Sinclair said, ‘allowed the RERF researchers to state with confidence that excess cancer risk due to radiation was observed at doses as low as 50 mSv.’ (Nucleonics Week 1996)

"Statistical analysis of the excess solid cancer deaths following exposures of 5 rem (P=0.11) and 15 rem (P=0.42) demonstrate that they are not statistically significant; the lowest significant DS86 dose for increased solid cancer mortality is 35 rem (p=0.002) [for colon cancer]. The correct dose for this significant increase is considerably greater than 35 rem since the revised DS86 dosimetry used gives estimates for neutron radiation from the Hiroshima atomic bomb that are lower by an order of magnitude than both the original T65D dosimetry and the experimental values obtained from neutron activation measurements at the distances from the hypocenter that correspond to low-dose exposures. (Kondo 1993)"