Question

1. What is meant by the “Relative Biological Effectiveness" and the "Oxygen Enhancement Ratio" of an ionizing radiation? 2. What factors are involved in the sensitivity of a particular tissue to radiation damage? How do the terms “VIM", "DIM”, “MCT”, “RPM” and “FPM" relate in this regard. 3. Describe briefly the differences between "early" and "late” effects of radiation damage as well as describe what “Acute Radiation Syndrome (ARS)” is and give a description of biological mechanisms that are involved in producing ARS.

Answer 1

1- Relative biological effectiveness—it is the ratio of biological effective of one type of ionizing radiation relative to other.

Oxygen enhancement ratio— it refers to the enhancement of therapeutic effect of ionizing radiation due to the presence of oxygen.