[ RadSafe ] RE: Radiation received in Taiwan Co-60 contaminated aprts most beneficial to people

[Marcel Schouwenburg]

Posted on behalf of Y.C.  Luan (please send replies to him using the 
email address mentioned below)
Senior Scientist of NuSTA and Consultant of NBC Society in Taiwan  . 
(yuan-chi luan <nbcsoc at hotmail.com>)

I am glad that Dr Rainer Facius from the Germen Aerospace center, and Dr 
John Jacobus the noted  US  certified health physicists are still trying 
in clarification the information and data appeared in the two papers 
about the Co-60 contaminated apartments in Taiwan.The clarification 
might be able to prove the truth of the health effects of radiation 
observed in the Taiwan Co-60 apartments, which might be in turn  
benefciall to the human beings in the peaceful uses of nuclear energy 
and the radiation application in  immunization and therapy of cancers. 
As an author of one paper, I would like to present some additional 
explanation based on my personal experience in this matter:

1. Dr Chang's paper indicated in its Table 3 that the SIR 95% CI for all 
cancers of 95-114.9  incidences to be  0.8, for all cancers except 
leukemia of 88-111.6 incidences to be 0.8, and for all solid cancers of  
82-109.5 incidences to be 0.8. All these data meant that the number of 
incidences observed were less than the predicated, or all the cancer 
risk should have been reduced. But the Table 3 also indicated the SIR 
for leukemia of 7-3.2 to be 2.2, and the SIR for thyroid cancer of 7-2.7 
to be 2.1 that meant the number os incidences observed were bigger than 
the predicated or meant the leukemia and thyroid cancer rick should have 
been increased, yet the leukemia is only about 2% and thyroid cancer was 
too tiny to be listed among in all 15 cancers in Taiwan ( the average 
cancer mortality for the total Taiwan population was 163.8 
persons/100,000 person-year in the first year moved to the apartments in 
1983 , the leukemia 204-208  was only 3.9/100,000), So that the data of 
leukemia and thyroid cancer did not had statistical significance.  

2.The most important data governing this matter was how the predicated 
incidence number obtained, there were 15 types vital deaths data listed 
in the National Mortality Registation of Taiwan (NCRT) system of the 
Department of Health (DOH), the cases or incidences of cancer were only 
statisticed by the hospitals. As Dr Chang's paper only statisticed the 
cancer incidences, the authors of Dr Chen's paper had contacted the 
doctors in the some important hospitals about incidences in Taiwan, no 
definite figures obtained, but the number of incidence of cancers is 
commonly two to three times higher than the number of the cancer deaths. 
So that the 95 of all cancers incidences among the irradiated residents 
is definitelly not a big number that could show the health effects of 
the low dose rate chronic radiation could  increase cancer risk, on the 
contral it is a  really a smaller number in comparing with the 232 
cancer deaths of the irradiated resicents, though the irradaited 
residents in two papers were not same, one is about 10,000 and another 
is in 7271.

3.The conclusion of Dr Chang's paper indicated the low dose rate chronic 
radiation could increase cancdr risk to the irradiated residents, 
especially to the subgroup under age 30. Age and sex adjustment in 
estimating of cancer mortality is usually required, but for estimating 
the Co-contaminated apartments in Taiwan, even in Atomic explosion in 
Japan, analysis of the biological effects reduced to the whole 
population would be most important data,  Ages and sexes adjustment are 
necessary for certain cohort with particular ages and sexes, as the 
cancer mortality of people in different ages would be so different, 
didfferent sexes would have some difference. Dr Chang's concluaiso 
emphysed the subgroup in age under 30 would cause confusion in 
estimation, for example, the cancer mortality of the people at ages 
15-19 and at ages 65-69 in Taiwan are respectly caculated to be 
52.3/100,000 and 1717.9/100,000 in 2005. The average mortality of all 
the  cancers for the total population in 2005 was 163.8/100,000 will be 
easy to calculated the total cancer deaths of the irradiated residents 
in Taiwan.

4. The RERF group did have obtained many valuable data in 40 years 
followed up of the health effects of the acute radiatian explosed to the 
Japanese survivors and used as basis for radiation protection by ICRP as 
Dr.Jacobus mentioned, but the biological effects of acute radiation from 
atomic bombs were completely different to these effects of  the  low 
dose rate chronic radiation to human health. The low dose rate chronic 
radiation even with the doses accumulated to high level still were 
benefical to people. Both the papers of  Dr Chang and Dr Chen had data 
indicated dose rate per hour high up to 1 mSv/hr and dose rate per year 
high up to 8 Sv/y in 1983, but the cancer deaths of irradiated residents 
were reduced to  only 7 uctil today, actually there should be about 270. 
So that the all the international radiation regulating agencies, such as 
ICRP should have different radiation protection policy and measures for 
the low dose rate chronic radiation which actually received by in the 
nuclear energy uses and the medical radiation application. Dr Chen's 
group in Taiwan had  many times suggested to  US DOE, IAEA and ICRP to 
revise the conventional radiation protection policy and reglulations.

5. Dr.Facius advised the Japanese ATB observation should be continued. 
The results of obervation of the Japanese survivors in 40 years 
conducted by RERF had obtained quite value data and published in the 
Radiation Research 146, 1-27 (1966). RERF had concluded the health 
effects of the acute radiation to the Japanese survivors who received 
the doses higher than 1 Sv, their solid cancer and leukemia mortality 
surely increased many times than the general population, and 
relationship betwen doses and cancer death rate could be in linear none 
threshold (LNT)model, and the leukemia deaths had appeared in a quite 
short times, might be an indicator to show radiation could cause 
leukemia. But the mortality of the surivors could be only observable in 
a smmal percentage of survivors who received in doses higher than 1 Sv, 
the majority of survivors received doese lower than 200 mSv, could not 
definitely show whether their cancer mortality increased or decreased. 
Therefore there were many scientists believe low dose radiation is 
harmless, even hormetic to human health, But from the data observed in 
the Taiwan contaminated apartments,the radiation might be benefical or 
hormetic to people was only limited to low dose rate chronic radiation, 
not the acute radiation from atomic bomb explosion. Dr, Luckey is the 
most important scientist believed in radiation hormesis, the radiation 
is also low dose rate chronic radiation. Dr. Luckey indicated in the 
complete dose-response curve in  his book" Radiation Hormesis" that when 
dose high up to 10 Sv/y is still hormetic to people. He also presented a 
paper in the 1999 ANS annul meeting indicated that if the US population 
were all exposed to a yearly doses through a public health system as the 
radiation doses avergely received by the nuclear workers, about half ot 
the cancer deaths in USA would be prevented.   

6. Dr Facius prefered also the natrual backgroud radiation (NB) might be 
a yardstick for assess of the health effects of radiation to human 
beings, as there are many areas in the world that have higher NB, but 
with lower cancer mortlity among the population, so  that people believe 
higher doses than NB received would be beneficial to people. My personal 
view to this based on the experience  is that when the radiation dose 
rate in the environment is lower than NB, the health of people woud be 
harmed, when the year dose rate about 20 to 50 times higher than NB, the 
cancer mortality of the people would be effectively reduced as though as 
immuned by vaccine. Dr Luckey also predicated in his book when the 
people received doses of about 100 mSv, the health effects of radiation 
would be  most optimum to people health (the average doses received by 
peole in the world is about 2.4 mSv/y )         

Best regards

Y.C.  Luan     Senior Scientist of NuSTA and Consultant of NBC Society 
in Taiwan  .
yuan-chi luan <nbcsoc at hotmail.com>