Vertex field verification in the treatment of central nervous system neoplasms

Increasing sophistication of computerized brain tumor treatment plans has enabled clinicians to devise increasingly complex field combinations to spare as much normal brain tissue as possible. These treatment plans often call for the use of a vertex field. This report describes a simple, useful technique for the verification of the vertex (or any non-coplanar) field on the treatment machine—a procedure that is impossible with conventional port film techniques.