Brachytherapy is a type of radiotherapy, or radiation treatment, offered to certain cancer patients. There are two types of brachytherapy – high dose-rate (HDR) and low dose-rate (LDR). LDR brachytherapy is the type that is most commonly used to treat prostate cancer; it may sometimes be referred to as 'seed implantation' or it may also be called 'pinhole surgery'.[1]