Radiation - Induced Cancer Risks

Who studies cancer risks

Risk estimates for radiation-induced cancer were first evaluated by scientific committees starting in the 1950s. The following bodies now study cancer risks:

  • The International Commission for Radiation Protection (ICRP)
  • The National Commission for Radiation Protection (NCRP)
  • The National Academy of Sciences Committee on the Biological Effects of Ionizing Radiation (the BEIR Committee)

These commissions and committees examine groups such as populations exposed to medical sources of radiation, to Japanese atomic bomb survivors, populations exposed to releases from Chernobyl, and to uranium miners, for instance.

What They Conclude

The BEIR Committee has issued several recent reports, including the BEIR IV and BEIR V reports. These reports state that:

  • "It is fair to say that we have more scientific evidence on the hazards of ionizing radiation than on most, if not all, other environmental agents that affect the general public." (NAS, 1980, p.11)
  • "It is not yet possible to estimate precisely the risk of cancer induction by low-dose radiation, because the degree of risk is so low that it cannot be observed directly and there is great uncertainty as to the dose-response function most appropriate for extrapolating in the low-dose region." (Ibid, p. 138)

The Linear No-Threshold Model

 These bodies conclude that, until further studies clarify the risk of cancer induction at low doses, it is prudent and conservative to use the linear no-threshold (LNT) model to estimate cancer risks.

Based on the known risk of cancer induction at high doses, the LNT model linearly extrapolates risks at low doses and assumes there is no threshold for cancer induction. Because we cannot prove there is no risk at very low doses, we conservatively assume that any amount of radiation, no matter how small, poses a cancer risk.

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