Quantenphysik der biologischen R�ntgenstrahlenwirkungen

Fundamentals of Microdosimetry

“…Let p be the density of the counting gas in grams per cubic centimeter. The value p then is also the ratio of the density of the counting gas to the density of tissue, which is assumed to be 1 g/cm 3 . If the counter has the diameter d*, the diameter of the equivalent tissue region is d -pd*.…”

“…Consider a spherical detector with a diameter of 1 cm that is filled with tissue-equivalent gas at atmospheric pressure (p -10 ~3 g/cm 3 ) and is exposed to a field of 15-MeV neutrons. The corresponding tissue site has a diameter of 10 fxm and the event frequency for 15-MeV neutrons is roughly 50/Gy (see Table I, Section II).…”

“…It was, therefore, natural that an attempt was made [2][3][4] to explain also curvilinear dose-effect relations in terms of random hits in hypothetical targets. An evident weakness of the approach has been the unrealistic assumption of equal, statistically independent hit events and of hypothetical, equal targets.…”

“…These approaches were aimed at an explanation of the shape of dose-effect relations in terms of the statistics of energy deposits that were termed hits and that were alternatively thought to be single ionizations [2], or events of point heat [3]. As a heuristic principle this interpretation was useful.…”