title: Use of surface markers for MR radiotherapy planning.
abstract: OBJECTIVE
  For the precise planning of radiotherapy treatment ports, the delineation and control of their borders has to be performed with X-ray and other imaging procedures before and during the therapy.
  
  
  METHODS
  Conventional planned therapy ports are checked with the help of MR-imaging with new gel-markers, as a further development to formerly used fluid filled tubes, on the skin of the patient in different regions. We describe the essentials of these gels and report about their first practical use.
  
  
  RESULTS
  Principal considerations to the technique and practical applications are given with imaging examples. The essential physical qualities of the gels are introduced with separate NMR experiments. It turns out, that multiplanar MR-imaging in combination with field markers on the skin is a fast simple and useful help for the control and the improvement of treatment planning.
  
  
  CONCLUSIONS
  MR-imaging with gel-markers on the skin in many cases can show the tumor and the field-ports in one picture. Thus the therapy planning is refined with simple means. On the one hand the target volume can be seized completely and on the other hand sensitive organs can better be protected.
authors.affiliation: Klinik und Poliklinik für Strahlentherapie, Universität, Göttingen.
authors.forename: G
authors.initials: G
authors.lastname: Fischer
authors.forename: D
authors.initials: D
authors.lastname: Matthaei
authors.forename: H P
authors.initials: HP
authors.lastname: Carduck
authors.forename: R
authors.initials: R
authors.lastname: Machinek
authors.forename: R
authors.initials: R
authors.lastname: Fietkau
authors.forename: E
authors.initials: E
authors.lastname: Dühmke
mesh_terms: D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*