Source of Support: None, Conflict of Interest: None
The use of modified linear quadratic model in radiotherapeutic practice is extended for fractionated
treatment regimes using the formula Em = N[a1d + a2d2 (TI N) -k]. This equation requires data on two important parameters viz. a1 / a2 & k, the values of which vary from tissue to tissue. To estimate a1 / a2, two methods are applied to radiation isoeffect data for spleen and kidney. The parameter k has been estimated from repair half life and cell doubling time of the tissue.