Cumulative radiation effect part I: Fractionated treatment regimes

Recurrence after Different Primary Treatment for Cancer of the Supraglottic Larynx

“…In evaluating the effect of radiation dose/time/ fractionation patterns, the formula of Kirk et al (2), described as the cumulative radiation effect (CRE) based upon the NSD concept of Ellis (3), was used as a convenient way of comparing the different methods. The possible limitations of these formulae, regarding the description of the true biological effects of the irradiation, have been appreciated (4).…”

Investigation of time-gap formulae on the CRE system using mouse tissue as a biological model

“…That curve was generated using the CRE parameters derived from human skin, but it can be readily demonstrated that the general features of Fig. 3, particularly the skewedness, are qualitatively the same for a wide range in values of the exponents of the CRE formulation for fractionated radiation schedules (Kirk et al, 1971). Therefore the small change in point of 32 crypts per circumference, a near-tolerance end-point chosen so that the effect of a gap in treatment could be investigated over as wide a range of tissue damage as possible.…”

“…The additional single doses, d, given on these regimes are given in the first and second lines in Table I, respectively. These experimental regimes can then be written explicitly as follows: Mean R = 2165 The CREs, R1 and R2, achieved by the first and second schedules, respectively, of these regimes taken alone can be evaluated using the formulation for fractionated treatment schedules presented in Kirk et al (1971): RF = D . N-0-24.…”

“…At present available methods of assessing radiation damage include several empirical mathematical descriptions such as NSD (Ellis, 1968), TDF (Orton & Ellis, 1973) and CRE (Kirk et al, 1971); and a semi-empirical computer model (Cohen, 1971). The CRE system is based on a monotonically increasing scalar assessment of biological effect, implying that a single number, the CRE, is taken to be a complete and unambiguous description of the level of biological effect generated by the radiation, regardless of the way in which the damage was inflicted.…”

Application of Radiation Effect Models in Combined External and Intracavitary Radiotherapy of Carcinoma of the Uterine Cervix

“…Kirk et al (9) extended the NSD equations to subtolerance levels of the normal tissue and termed it cumulative radiation etfect (CRE). Orton Douglas & Fowler (21).…”