title: [A multileaf collimator: additional quality assurance in a GE linear accelerator].
abstract: BACKGROUND
  In comparison to a conventional collimator, a multileaf collimator demands a great deal of quality assurance procedures due to its large number of leaves. A concept for daily quality assurance is presented, mainly concerning the positioning accuracy of the leaves.
  
  
  METHODS
  Two leaf configurations including maximal opening as well as overtravel of single leaves, at a maximal opening of the jaws, are transmitted online in daily exchange from our record- and verify system to the linac. Aiming at a special test phantom a visual control of the positioning accuracy is performed. The leaf positioning is documented by an electronic portal imaging system and is compared with a reference shot by superposition of a grid.
  
  
  RESULTS
  This method of quality assurance offers a fast and effective possibility to guarantee the proper function of the whole system by simulating the routine treatment situation.
  
  
  CONCLUSIONS
  Compared to a conventional collimator only a slightly greater workload is needed for quality assurance of a multileaf collimator.
authors.affiliation: Strahlentherapie und Radioonkologie, Klinikum Darmstadt. kd-strahlentherapie@t-online.de
authors.forename: K
authors.initials: K
authors.lastname: Hierholz
authors.forename: W
authors.initials: W
authors.lastname: Baus
authors.forename: K
authors.initials: K
authors.lastname: Müller-Sievers
authors.forename: B
authors.initials: B
authors.lastname: Kober
mesh_terms: D004867:Equipment Design; D006801:Humans; D010315:Particle Accelerators / Q000295:instrumentation* / Q000592:standards; D011786:Quality Control; D011879:Radiotherapy Dosage