ABSTRACT
The term brachytherapy refers to treating tumours from a short distance, in contrast to
teletherapy, where tumours are treated at a long distance from the radiation source.
Brachytherapy is usually achieved by placing radioactive sources on or in the tissue to be
irradiated. In teletherapy, tissue absorption largely governs dose distribution, whereas the
inverse square law is most responsible in brachytherapy. Whereas teletherapy is designed
to produce a homogenous dose distribution in most cases, brachytherapy uses the
inhomogeneous dose distributions found around sources to create a high dose in tumours,
whilst producing a low dose in normal tissue.
