Use of CRE instead of TDF

The nominal standard dose concept proposed by Ellis 1967) for comparison of various treatment regimes has been widely accepted. The nominal standard dose is associated with treatment schedules which lead to full tolerance of tissue. Using this idea, Kirk et al. (1971) have proposed the use of Cumulative Radiation Effects (CRE) at the partial tolerance level. Orton and Ellis (1973) have proposed time, dose, fractionation factors for dealing with treatment schedules leading up to and including tolerance. A question, therefore, arises which of these two concepts should be used for dealing with problems of radiotherapy at the present juncture.