| Abstrakt: |
Carcinoma of the cervix is shortly to be treated using a high dose-rate intracavitary unit which delivers dose-rates 100 times greater than those obtained using the radium technique at present in use at this centre. Cell survival theory has been applied to the existing radium treatments to estimate the levels of damage produced in the tumour and in the surrounding healthy tissue structures. An attempt has then been made to predict regimes of fractionated treatment at the high dose-rate, which will as nearly as possible match the effect of the radium treatment on the tumour and which will, it is hoped, produce less damage to the surrounding healthy tissue structures.For the purpose of the calculations, the various structures irradiated have been divided into two types. Type 1 structures are defined as structures with cell cycles sufficiently long to prevent complete repopulation occurring between consecutive doses of radiation, which consequently have a cumulative effect. Type 2 structures are defined as structures capable of rapid cell division and which consequently restore their cell populations to normal between one dose and the next, provided the first dose is not sufficiently large to denude the structure of viable cells. |
