title: Patient positioning variations to reduce dose to normal tissues during 3D conformal radiotherapy for high-risk prostate cancer.
abstract: OBJECTIVE
  The goal of this work was to assess optimal treatment positioning of 3D conformal radiotherapy (3DCRT) for high-risk prostate cancer patients.
  
  
  METHODS
  Treatment plans of 25 patients in different patient positions were evaluated: with knee and ankle support (KAS) in the supine position and with a belly board (BB) in the prone position both with full (FB) and empty bladder (EB). Planning target volumes (PTVs) for pelvis, prostate and vesicles, prostate, and organs at risk (OARs) were delineated. Dose and overlapping volumes were evaluated.
  
  
  RESULTS
  Overlapping volumes were significantly smaller with a FB than with an EB. No significant differences were found in overlapping volumes with respect to patient fixation systems, but the percentage values of dose to the OARs showed significantly better results employing KAS than a BB. A FB reduced the dose volumes to the OARs. Comparison with respect to circumference of abdomen (CA) showed significantly smaller overlapping at large CA in most of the cases.
  
  
  CONCLUSIONS
  Supine position is suggested with KAS combined with a FB (especially in cases of larger CA) when using 3DCRT with planning technique modification for high-risk prostate cancer patients to reduce the dose of OARs, based on our results.
authors.affiliation: Department of Radiotherapy, National Institute of Oncology, Budapest, Hungary. kczigner7@yahoo.com
authors.forename: K
authors.initials: K
authors.lastname: Czigner
authors.forename: P
authors.initials: P
authors.lastname: Agoston
authors.forename: G
authors.initials: G
authors.lastname: Forgács
authors.forename: M
authors.initials: M
authors.lastname: Kásler
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D056888:Patient Positioning / Q000379:methods*; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000517:prevention & control; D011835:Radiation Protection / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods*; D016896:Treatment Outcome