Comparison of the LET-dependent behaviour of gentoxic endpoints and TLDs after proton irradiation

Irradiation of blood samples was performed in a modulated and an unmodulated 62 MeV proton beam in the dose range of 0.25 to 3 Gy. To determine the dose and the linear energy transfer, thermoluminescence dosemeters were attached in front of and behind the sample. A single chip calibration was carried out for measurement of the absorbed dose. The values of absorbed dose and high temperature ratio are given for proton irradiation in depths of 10 and 25 mm and for Co-60 irradiation. The results obtained with the high temperature ratio method show an excellent agreement with the biological investigations of micronucleus induction. The observed correlation of relative biological effectiveness and the high temperature ratio is assumed to be due to similar mechanisms which are responsible for the occurrence of the biological effect and for the dependence of thermoluminescence emission on the linear energy transfer and the dose. (A.K.)