Brachytherapy works by targeting the cancerous tumour from inside the body. The source of radiation is placed directly inside or next to the tumour. This approach reduces the risk of damage to healthy tissue and organs that are close to the tumour.

Usually, brachytherapy is used to treat prostate, breast, cervical and oesophageal cancer. 

High-dose-rate (HDR) brachytherapy uses a relatively intense source of the radiation (Iridium 192) delivered through temporarily placed applicators.

Radiation source is usually attached to (or embedded in) the end of a wire or cable. The wire drives the catheters into applicators that have previously been placed in the patient. The source placed in a pre-planned position for a pre-set time, before stepping along the catheter. This process repeats itself to create the required dose distribution.

By varying the position and time of the radiation source, the dose is neatly sculpted to conform to the shape of the target. The patient typically receives the total dose in a series of 2-10 treatment sessions, also known as fractions.