I disagree with "... we don't know what is going on at low levelsof dose."

[John Cameron <jrcamero@wisc.edu>]

Dear Colleagues: Mike Stabin wrote (in part):  I believe that anyone 

who is honest with the data will admit that at this point in time we 

don't know what is going on at low levels of dose."  I strongly 

disagree. I know a number of eminent scientists who strongly disagree 

with the LNT. A few that come to mind: Lauriston Taylor, Victor Bond, 

Myron Pollycove, Ludwig Feinendegen and the authors of the book:

  Radiation Protection Dosimetry - A Radical Reappraisal

by Jack Simmons and David Watt (Medical Physics Publishing about 1998)

Three of the  major conclusions of the book are:

1. Weighting coefficients and risk factors derived with their use are 

meaningless numbers when used for calculating radiation protection 

dosimetry.



2. To deny the existence of a threshold for the induction of cancer 

by radiation is to fly in the face of a large body of evidence 

supporting its existence.



3. The postulate of a linear response as a function of dose is, at 

best, a crude approximation and, at worst, an extremely expensive way 

to over-estimate risk.



	In 1973 Frigerio et al showed conclusively (i.e., high 

statistical strength) that the states with the highest background 

radiation levels have 15% lower cancer mortality than the average for 

all states. In 1998 Jagger showed that three mountain states with 

high background had a cancer mortality about 25% lower than three 

U.S. Gulf States with a background only one-third of that in the 

moutain states. (Again, very high statistical strength.)

	The nuclear shipyard worker study showed that the nuclear 

workers had 15% lower cancer mortality (p<0.01) than the controls. 

More importantly they had a 31% lower death rate from non-cancer (16 

std. dev.). Their death rate from all causes was 24% lower than the 

controls (p<10^-16).

	The 100-year study of British radiologists showed that after 

1920 they never had a significantly increased cancer death rate and 

that for the 100 years their death rate from non-cancer was 14% lower 

than their male medical colleagues. Their dose rate about 1920 was 

estimated to be about 0.5 Gy/y. For the most recent group studied 

(1955-1979) their cancer mortality was 29% lower (NS) and their death 

rate from non-cancer was 36% lower (p<0.001) and their death rate 

from all causes was 32% lower (p<0.001).

	Where are the human studies that support the LNT in the dose 

range <0.2 Gy?

	I do not know what fraction of our colleagues agree with the 

statement "we don't know what is going on at low levels of dose."  We 

shouldn't let private organization who choose their own members 

(i.e., ICRP and NCRP) distort our view of radiation health effects. 

I believe we have excellent evidence that there is no increase of 

cancer in high background areas. There is even better evidence of 

greatly reduced deaths from non-cancer at at occupational dose rates 

up to about 1 Gy/y (i.e., early British radiologists).

	We know what is going on at low dose rates if we exclude 

a-bomb survivor data. The health effects of instantaneous doses 

radiation on a-bomb survivors  are  inappropriate for predicting 

health effects at the low dose rates of radiation workers. The dose 

group of a-bomb survivors who had a 75% increase in cancer deaths 

had a similar numerical increase of non-cancer deaths. This  is 

grossly different than  the results of the early UK radiologists 

(1897-1920) who had a 75% increase in cancer deaths but a 14% 

decrease (p<0.05) in non-cancer deaths. This huge discrepancy in 

non-cancer deaths invalidates the use of a-bomb data for longevity 

studies, the best measure of health effects of radiation (see last 

reference below).

Best wishes,

John Cameron

References:



1. Frigerio, N.A., Eckerman, K.F. and Stowe, R.S. (1973) Carcinogenic 

Hazard from Low-Level, Low-Rate Radiation, Part I, Rep. ANL/ES-26. 

Argonne Nat. Lab



3. Jagger, J Natural Background Radiation and Cancer Death in Rocky 

Mountain and Gulf Coast States Health Physics Oct. pp 428-434 (1998)



4. Matanoski, G.  1991.  Health effects of low-level radiation in 

shipyard workers.  Final report. 471 pp.  Baltimore, MD, DOE 

DE-AC02-79 EV10095.



5. Sponsler, R. Cameron, J.R.  Nuclear shipyard worker study 

(1980-1988): a large cohort exposed to low dose-rate gamma 

radiation.    http://www.medphysics.wisc.edu/~jrc/art_nsws1.htm



6. Berrington, A, Darby, SC, Weiss, HA, Doll, R. 100 years of 

observation on British radiologists: mortality from cancer and other 

causes 1897-1997 Br J Radiol. 74, 507-519 (2001)



7.  Cameron, J. R. Radiation increased the longevity of British 

radiologists. Br J Radiol 2002; 75: 637-8.



8. Cameron, J.R. Longevity is the most appropriate measure of health 

effects of radiation Radiology 299 (1); 14-15 2003



The following  two references show thresholds for cancer of 2 Gy and 

10 Gy, respectively:



Rossi, H.H. Zaider, M. Radiogenic lung cancer. The effects of low 

doses of low-LET radiation. Rad. and Env. Biophys. 36(2): 85; 1997.



Evans, R.D. (1974) Radium in man Health Physics 27, 497-510.



-- 

John R. Cameron (jrcamero@wisc.edu)

(until 10/18/03) E2571 Porter Rd.  PO Box 405, Lone Rock,WI 53556 

Phone:608) 583-2160

(After 10/31/03) 2678 SW 14th Drive, Gainesville, FL 32608 Phone: 352/371-9865



Visit  the Virtual Radiation Museum  (VRM) at 

http://www.medphysics.wisc.edu/~vrm

and my web page at  http://www.medphysics.wisc.edu/~jrc/