Brachytherapy is a procedure in which radioactive material sealed in needles, seeds, wires or catheters is placed directly into or near a tumour (also called internal radiation, implant radiation or interstitial radiation therapy). This book provides practical guidance on the use of brachytherapy. It takes the reader through the basic principles and covers physics, dosimetry and protection issues, before developing this by discussing individual sites on which the procedure can be used.