title: A clinically practical electron cone for the treatment of head and neck cancer.
abstract: OBJECTIVE
  The purpose of the work was to develop a practical electron cone and to compare its dosimetry with that of the conventional applicator collimation system.
  
  
  METHODS
  The electron cone consists of the upper part of a manufacturer-supplied electron applicator and an institution-built rectangular extension tube which produces a 12 cm x 6 cm field at 100 cm SSD while maintaining an air gap of 5 cm between the patient.
  
  
  RESULTS
  The compact size of the cone allows electron irradiation without having to reposition the patient after photon treatment. The radiation field is very similar to that of a standard 15 cm x 15 cm applicator with a 12 cm x 6 cm field restricting insert. Radiation leakage at the surface of the special cone is typically less than 1% of the useful beam at dmax. During 12 years of clinical use the special cone proved itself very practical in the treatment of more than 300 patients.
  
  
  CONCLUSIONS
  An electron cone practical for clinical use with dosimetry comparable to the conventional applicator was developed.
authors.affiliation: Department of Radiation Oncology, University of Alabama at Birmingham 35233.
authors.forename: I A
authors.initials: IA
authors.lastname: Brezovich
authors.forename: P N
authors.initials: PN
authors.lastname: Pareek
authors.forename: S A
authors.initials: SA
authors.lastname: Spencer
authors.forename: M M
authors.initials: MM
authors.lastname: Salter
authors.forename: R Y
authors.initials: RY
authors.lastname: Kim
mesh_terms: D004583:Electrons; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D011879:Radiotherapy Dosage