A probabilistic approach to relate microdosimetry, biological effects, and radiation quality

Microdosimetry-based cellular response functions are derived from dose-effect relations for different biological endpoints, including those relevant for radiological protection. For this purpose, a probabilistic approach is being applied that makes use of measurable microdosimetric spectra and avoids controversial assumptions concerning principal mechanisms of radiation action. Instead, statistical distributions are applied and their parameters evaluated in order to characterize the sensitive target structures within cells. Resulting functions can be used for predictions of both low- and high-dose radiation effects, including those of ultra-soft x rays, and thus may be useful for on-going revisions of radiation quality specifications. They can also be directly applied in radiation-protection metrology by incorporating them into the software used to process the readings of microdosimetric spectrometers. Results of the analyses are compared with experimental data not used in fitting parameters, and with predictions from other phenomenological or ''mechanistic'' approaches