Megavoltage Treatment Planning and the Use of Xeroradiography

The problem of viewing the emergent ray image from a Treatment Planning Simulator is met by the use of xeroradiography. With this a finished picture is obtained within 10 seconds of completion of the X-ray exposure, which may be studied as a basis of further beam adjustment, or photographed if desired. This technique has the advantage over film, not only of speed in processing, but of showing soft tissue detail, bone detail, air passages and skin outline, all within the same X-ray exposure range. The Simulator at Newcastle on Tyne is described and illustrations of its use in relation to the 4 MeV linear accelerator are given.