Applied Radiation Biology and Radiotherapy (ARBR)
Teletherapy is usually clinically administered by electro-magnetic radiation as photons of x-rays or gamma rays, or electrons.
There are alternative methods of irradiating tumours, some virtually abandoned e.g. fast neutrons, and some under investigation e.g. protons, heavier ions, and boron neutron capture therapy. Protons have the advantage over photons of a much more sharply defined beam, so that the dose to normal tissue can be reduced. Heavier ions also have this property, as well as being more effective per unit dose in killing cells and being less dependent on the presence of oxygen for maximum effect. In boron neutron capture, tumours containing boron are irradiated with low energy (epithermal) neutrons to produce short-range alpha particles which are very efficient in killing cells. All these techniques are under development.