Source of Support: None, Conflict of Interest: None
The linear quadratic (LQ) model has recently been modified by incorporating a time factor. The modified LQ (MLQ) model has a number of applications in which the alterations of dose per fraction in fractionated radiotherapy may be used to bring out improved results with respect to early / late normal tissue and tumour reactions. In this paper, the MLQ model is used to determine the total dose for early / late normal tissue reactions and tumour response. The normal tissues are classified in three main groups on the basis of their reactions. Different values of a1 / a2 and k are used for the three groups of normal tissues and tumours to calculate the equivalent total doses for various treatment regimes.