| Popis: |
Purpose: To compare clinical results from accelerated partial breast irradiation with predictions from different half-times of recovery of radiation damage. Method: Three published results of excessive late complications led to an editorial which was a “wake up call” to the possible hazards of fractions spaced close together such as two fractions of 3.85 Gy a day on five consecutive days. These results are re-examined here using linear quadratic modelling with mono-exponential and bi-exponential recovery kinetics. Results: Although clinical results showed rather high proportions of severe complications, only in one of the three studies discussed in reference [1] complications were severe enough to cause it to be terminated. Since then other studies with the same doses have reported acceptable results. However, none of these complication rates are predicted to be tolerable, if mono-exponential kinetics with a single T ½ of ~4 hours is assumed. Conclusions: Better matches to clinical results can be found by assuming bi-exponential recovery with 50%-50% components of 0.3 hand 4 h, and α/β = 3 Gy, for late complications. There is continuing need for data from more clinical results, especially concerning various tumour types. |
