Theoretical and experimental investigations of a newly developed intracavitary applicator system for the radiothermotherapy of gynaecological tumours

This paper describes a new type of applicator system for the intracavitary radiothermotherapy of gynaecological tumours. Hyperthermia and radiation can be delivered by one and the same applicator. The hyperthermia is delivered by a modified capacitive heating technique (27.12 MHz) combined with cooling systems, the radiation by the numerically controlled oscillation of a gamma source on the inside of the main applicator, the RF gamma applicator (HDR afterloading technique). Isotherms and isodoses can be adapted to the anatomical-pathological situation. Interactions between the applicator system and the surrounding tissue were investigated in a theoretical model (FEM). Complex two-dimensional SAR calculations as well as three-dimensional temperature calculations were carried out. The RF gamma applicator was also examined by thermography; the thermography proved the theoretical modelling to be correct. The applicators were also tested in animal experiments.