Comparing radiation quality(Please click illustration.)
This chart illustrates the Linear Energy Transfer (LET) of ionising radiation and helps to explain the effect that different internal exposures with different radiation quality, alpha, beta and gamma, have on the cell.
The release of energy along the path travelled by the particle or ray, causes ionisation of the tissue - creating free radicals11 and other ionisation products. The dose to the individual cell is the critical concern in radiation exposure. Therefore the radiation quality - or the amount of energy and the pathlength of the particle or ray - determines the dose (energy per gram which equals ergs). Alpha particles have the shortest pathlength, 30-40 microns or 1-2 cells. A Uranium-238 atom releases an alpha particle with an energy of 4.039 MeV, and a Plutonium-239 has an alpha energy of 5.244 MeV. The difference is little when one considers that the molecules within the cell have a binding energy of less than 10eV. Beta particles have a less harmful effect because they travel a longer distance, and have a lower LET. Thorium-234, the daughter product of Uranium-238 is a beta emitter with a beta energy of 0.270 MeV, which means it has a much lower LET than Uranium-238. Uranium-238, Plutonium-239 and Thorium-234 are also gamma emitters. Gamma rays have a spectrum of energies and a much longer path of travel. The gamma ray for Uranium-238 has an energy of 0.048MeV. The LET for gammas is much lower than for alpha or beta particles. Alpha particles have such a high energy density that it is evident that cells may not repair themselves. There are repair mechanisms for beta particle and gamma ray damage to be repaired by the cell. But the cell may not repair itself properly, i.e after repair it may not be the same as it was before the damage occurred.
ECRR: Executive Summary
The European Committee on Radiation Risk (ECRR) concludes:
"The present cancer epidemic is a consequence of exposure to global atmospheric weapons fallout in the periods 1959-1963 and that more recent releases of radioisotopes to the environment from the operation of nuclear fuel cycle will result in significant increases in cancer and other types of ill health."
"Using both the ECRR's new model and that of the International Committee for Radiation Protection (ICRP), the committee calculates the total number of deaths resulting from the nuclear project since 1945. The ICRP calculation, based on figures for doses to populations up to 1989 given by the United Nations, results in 1,174,600 deaths from cancer. The ECRR model predicts 61,600,000 deaths from cancer, 1,600,000 infant deaths and 1,900,000 fetal deaths. In addition the ECRR predicts a 10% loss of life quality integrated over all diseases and conditions in those who were exposed over the period of global weapons fallout." 2 (p. 182-183)
The European Committee on Radiation Risk (ECRR) concludes:
"The present cancer epidemic is a consequence of exposure to global atmospheric weapons fallout in the periods 1959-1963 and that more recent releases of radioisotopes to the environment from the operation of nuclear fuel cycle will result in significant increases in cancer and other types of ill health."
"Using both the ECRR's new model and that of the International Committee for Radiation Protection (ICRP), the committee calculates the total number of deaths resulting from the nuclear project since 1945. The ICRP calculation, based on figures for doses to populations up to 1989 given by the United Nations, results in 1,174,600 deaths from cancer. The ECRR model predicts 61,600,000 deaths from cancer, 1,600,000 infant deaths and 1,900,000 fetal deaths. In addition the ECRR predicts a 10% loss of life quality integrated over all diseases and conditions in those who were exposed over the period of global weapons fallout." 2 (p. 182-183)