Stochastics of HZE-induced microlesions.
Fundamental biological experiments with bacteria, yeast, and mammalian cells irradiated with ions heavier than helium indicate that maximal probability of single-hit inactivation does not occur when the ion has LET below about 100-200 keV/micrometer.  Theoretical treatments of cell inactivation data and the radiation chemistry in particle tracks are consistent with this finding.  If a "microlesion" is defined as a linear array, within a tissue, of cells inactivated with maximum probability, surrounded by non-lethally damaged cells, then, by this definition, there must be an LET below which "microlesion" damage cannot be expected.  In a retrospective survey of experimental literature in which single-particle effects in tissues were sought, it was found that little or no evidence has been reported supporting single-particle effects in tissues when LET was below 200 keV/micrometer, while some experimenters who irradiated tissues with particles having LET greater than 200 keV/micrometer reported effects that could be attributed to single-particle tracks.
Todd
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Boulder, CO 80303.
D000818:Animals; D001853:Bone Marrow / Q000473:pathology / Q000528:radiation effects; D016923:Cell Death / Q000528:radiation effects; D002467:Cell Nucleus / Q000528:radiation effects; D002478:Cells, Cultured; D003359:Cosmic Radiation / Q000009:adverse effects*; D004307:Dose-Response Relationship, Radiation; D007422:Intestines / Q000473:pathology / Q000528:radiation effects; D007477:Ions; D018499:Linear Energy Transfer / Q000528:radiation effects; D051379:Mice; D011833:Radiation Injuries, Experimental / Q000473:pathology*; D013269:Stochastic Processes
D007477:Ions