Visualization and Transport of Positron Emission from Proton Activation in vivo.

Heavy charged particle beams can be widely used for cancer therapy if control in heterogeneous tissue is proved practical. A beam of protons at 200 million electron volts has been visualized in plastic and in a living animal by using an on-line positron camera. The fraction of the activity retained in the radiation site was found to be at least 70 percent of that produced in a dead animal. The sensitivity of the technique was established for a typical geometry.