[Prospective prediction of radiotherapy induced normal tissue injuries]

Variation of the normal tissue response to radiotherapy in animals of a given age, sex and species, and predictive analysis of the post radiotherapy normal tissue injuries for each case were reviewed. The degree of response of mouse hind legs to 25 Gy in a single dose varies from less than 20 Gy equivalent to more than 30 Gy equivalent injuries, implying that there still remains an unknown dose modifying factor whose modification factor is at large. It has been proposed to predict prospectively the post irradiation response of several normal tissues including the lung. Although, it is possible to predict the average degree of normal tissue injuries to a given dose, to predict the response of each case appears to be impossible.