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.

Neutron therapy for locally advanced head and neck squamous cell carcinoma: optimum dose search.

28 patients with locally advanced primary squamous cell carcinoma of the head and neck received neutron therapy and were randomized between two dose levels: 145 cGy n gamma x twelve fractions, three fractions per week (total 17.4 Gy n gamma). 155 cGy n gamma x twelve fractions, three fractions per week (total 18.6 Gy n gamma). Acute toxicity for skin, mucous membrane, salivary and subcutaneous tissues was graded using the EORTC/RTOG scoring system. Analysis indicates 17.4 Gy n gamma as "safe". A further twelve patients are to be assigned to the higher dose (18.6 Gy n gamma) before making a final dose selection.