Limiter for beam of radiation, used esp. in radiotherapy - esp. where two limiters can be driven in two coordinate directions and swivelled to restrict width and penumbra of beam

摘要

A source is located in a container which has a window for a beam of radiation emitted by the source; the beam has a main direction (A) of reference. The beam limiter consists of at least one block (a) which can be driven in a direction (Y) at 90 deg. to direction (A). Block (a) can be driven on rollers in direction (Y), and by a threaded spindle in direction (A). Block (a) has a pivot mounting for a block (b) so the latter can be swivelled on a third coordinate axis; and block (b) has a main surface limiting the radiation beam and minimising the penumbra. Several such pairs of blocks (a,b) are pref. used on a collimator, esp. in radiotherapy or radiodiagnostics.