Radical radiotherapy for carcinoma of the uterine cervix using external beam radiotherapy and a single line source brachytherapy technique: The Clatterbridge technique

At the Clatterbridge Centre for Oncology, a single line source brachytherapy technique using the Selectron (Nucletron) low dose rate remote afterloading equipment has been developed for use in conjunction with homogenous whole pelvis external beam radiotherapy in the radical treatment of carcinoma of the cervix. The technique incorporates several modifications aimed at reducing treatment related morbidity while maintaining satisfactory local tumour control and cure rates. A flexible dose prescription system has been devised to allow individualization of the brachytherapy isodose distribution according to the clinical findings and the estimated normal tissue doses. Modifications of source loading distributions are carried out to limit the point 'A' dose rate to a narrow range to take into account the dose rate effect on the risk of complications. Source loading distributions are also modified according to the estimated normal tissue doses in order to respect normal tissue tolerance. This paper describes the technique and its underlying principles.