Possible biomedical applications of antiproton beams: focused radiation transfer.

A calculation of the energy lost by antiprotons stopping in water shows that the radiation transferred is localized within 1 mm of the stopping point. This "focusing" of the radiation is mainly due to heavily ionizing particles emitted from the nuclei on which the annihilation takes place. At present antiproton beams for medical purposes may not be cost effective compared to other charged particle beams, but the sharpness of their radiation transfer combined with antiprotonic radiography are highly attractive and unique features that may invite special applications.