Alternative irregular field collimation for fast neutron therapy

The neutron therapy program at the King Faisal Specialist Hospital and Research Centre was resumed in the spring of 1987. Due to the limited number of standard treatment cones, some form of beam modification was necessary. Originally we chose a cast iron blocking system, as adopted by other neutron treatment centers. For several reasons we found this arrangement to be generally unsatisfactory and inconvenient. We therefore, developed an alternative collimation system which resolved our earlier difficulties.