The associations
between radiation exposure and cancer are mostly based on
populations exposed to relatively high levels of ionizing radiation
(e.g., Japanese atomic bomb survivors and recipients of selected
diagnostic or therapeutic medical procedures). Cancers associated
with high dose exposure include leukemia, breast, bladder, colon,
liver, lung, esophagus, ovarian, multiple myeloma, and stomach
cancers. Literature from the U.S. Department of Health and Human
Services also suggests a possible association between ionizing
radiation exposure and prostate, nasal cavity/sinus, pharyngeal and
laryngeal, and pancreatic cancers.
Those cancers that may develop as a result of radiation exposure are
indistinguishable from those that occur naturally or as a result of
exposure to other chemical carcinogens. Furthermore, literature from
the National Cancer Institute indicates that other chemical and
physical hazards and lifestyle factors (e.g., smoking, alcohol
consumption, and diet) significantly contribute to many of these
same diseases.
Although radiation may cause cancer at high doses and high dose
rates, public health data do not absolutely establish the occurrence
of cancer following exposure to low doses and dose rates below about
10,000 mrem (100 mSv). Studies of occupational workers who are
chronically exposed to low levels of radiation above normal
background have shown no adverse biological effects. Even so, the
radiation protection community conservatively assumes that any
amount of radiation may pose some risk for causing cancer and
hereditary effect, and that the risk is higher for higher radiation
exposures.
A linear no-threshold (LNT) dose-response relationship is used to
describe the relationship between radiation dose and the occurrence
of cancer. This dose-response model suggests that any increase in
dose, no matter how small, results in an incremental increase in
risk. The U.S. Nuclear Regulatory Commission (NRC) accepts the LNT
hypothesis as a conservative model for estimating radiation risk.
New Zealand
Eritrea, Asmara
New Zealand
Morocco, Rabat
Chile, Santiago
Zambia, Lusaka
Vanuatu, Port Vila
Maryborough, Queensland St. Petersburg, Florida, USA
Antigua and Barbuda, St. John's
