Frankly, physics professor Wade Allison's references to radiotherapy are so far off the mark that all of his recommendations are questionable. Radiotherapy is applied to kill cancer cells, but unaffected cells need to be carefully shielded from the very harmful radiation beam usually emitted by a linear accelerator. To quote the radiation dose that cancer patients are exposed to as any kind of benchmark in the presumption of human safety is ridiculous.

Even a comparison using a CT or PET examination is off the mark in this case. Any radiologist worth his title will carefully weigh the risks and benefits of the dose he exposes a patient to before he carries out an examination. He will be even more careful before treating children or pregnant woman. Furthermore, the average patient receives such treatment very few times during a lifetime.

When it comes to radiation risks, don't believe what a physicist says; ask a biologist or an oncologist.

The opinions expressed in this letter to the editor are the writer's own and do not necessarily reflect the policies of The Japan Times.

manfred baur