New sources of neutrons and heavy charged particles for use in medicine and biology

Some characteristics are discussed of new radiation sources used in radiobiology and radiotherapy. These are mainly sources of intermediate neutrons which in therapy eliminate the disadvantage of thermal neutron beams. Proton accelerators are beginning to be used as fast neutron sources which provide a lower neutron yield but are otherwise in every way more advantageous than the ''classic'' fast neutron sources used hitherto. Attention is also centred on proton sources. It is stated that the number of countries and workplaces using proton therapy is constantly increasing. (Z.M.). 10 figs., 4 tabs., 44 refs