The American Journal of Roentgenology, Radium Therapy, and Nuclear Medicine
Calculation of isodose patterns for high energy therapy units using Cunningham's BEAM program requires accurate information on the beam profile in air. This may be obtained by scanning across the x-ray beam using a very small silicon diode detector. Data obtained on a particular unit may not be applicable to any other unit. Computer calculations of isodose curves for high energy x-ray machines must use a 0.25 cm. or smaller lateral grid of dose calculation points to ensure accurate reproduction of the sharp fall-off of the dose at the beam edge.