These radioactive emitters, which are the size of a grain of rice, are referred to as seeds. The 5-mm long seeds are covered with a titanium shell in order to prevent adverse tissue reactions. Depending on the selected activity of the seeds and the size of the prostate, we implant between 40 and 60 seeds.
After careful calculation and with the help of an ultrasound and target grid, they are guided from the perineum into the prostate by means of a cannula. The radiation emitted by the seeds kills tumour cells. The seeds emit a low dose rate over several months, thereby reducing adverse effects. Iodine 125 has a half-life of about 60 days; after 9–10 months, there is no longer any radiation.
Because these emitters have a low penetration depth, the surrounding tissues such as the rectum, potency nerve fibres, and the sphincter remain protected. With respect to radiation protection, no special measures must be taken for the patients or the environment.
Brachytherapy is planned and implemented in close collaboration between urologists, radiation physicists, and radiation therapists. In Switzerland, brachytherapy is offered only by specialised hospitals, including Uroviva Klinik AG.
In Europe, brachytherapy is being used more frequently for treating localised prostate cancer. Long-term studies from the US have revealed that with respect to tumour healing, brachytherapy yielded results equivalent to those obtained following surgical removal of the prostate or external radiation. Following brachytherapy, the side-effects – especially with respect to potency and continence – appear to be less pronounced than they are following radical surgery or external radiation.
Therapy in images and sound