Use of electrons for radiation therapy in France.

: The development of high energy radiotherapy equipments in France between 1950 and 1990 is analyzed. The use of betatrons after a growth between 1960-1970 decreased progressively from 1975 in favour of linear accelerators (133 in 1989). Cobalt-therapy, rapidly grown up between 1960 and 1980, has reached a plateau phase with a trend to being progressively substituted by low energy linac. The dosimetric aspects are considered: calibration of electron beams, quality control and treatment planning. About 22000 cancer patients were treated in 16 Centres in 1983; of these only 23% (mean value) received electron therapy, but the number varies greatly from one center to another (9-45%). The major indications for electrons in France are: neck nodes, operated breast, internal mammary chain. The general trend is to restrict their use to lesions not deeper than 4-5 cm and first of all to employ them as a boosting treatment, after an X ray irradiation.