title: Sparing the posterior surgical site when planning radiation therapy for thoracic metastatic spinal disease.
abstract: BACKGROUND
  Most patients with painful spinal metastases are sufficiently palliated by hypofractionated radiotherapy. However, a small group of patients will need surgical intervention to treat symptomatic spinal cord compression and/or gross mechanical instability. Irradiation of a (prospective) surgical area may lead to postsurgery complications, including wound dehiscence, infection, and chronic wound ulcers. Decreasing the radiation dose to the surgical area could reduce radiation-induced toxicity and associated surgical complications.
  
  
  OBJECTIVE
  To investigate an alternative radiation technique designed to lower the surgical area dose while delivering an adequate target dose and minimal off-target dose.
  
  
  METHODS
  Comparison of radiation doses received by various anatomic structures after simulating irradiation with a routine posteroanterior single field (SF) technique and experimental multiple field (MF) technique in a setting of thoracic metastatic spinal disease.
  
  
  METHODS
  The computed tomography (CT) data from six previously treated patients with a total of 10 thoracic spinal metastases were used to plan four radiation schemes (SF8 Gy; SF20 Gy; MF8 Gy; and MF20 Gy). Discrete anatomic structures were defined on CT data, including a posterior surgical area, and after simulation the doses received were calculated and compared for the 8 Gy and 20 Gy techniques.
  
  
  RESULTS
  With the experimental MF technique, a clinically relevant dose could be delivered to the affected vertebra, whereas the dose received at the (prospective) surgical area could be significantly reduced compared with the SF technique. The dose received at the nontarget tissues fell below the threshold level for clinical relevance.
  
  
  CONCLUSIONS
  This radiation planning study showed the feasibility of sparing the surgical area while delivering an adequate dose to affected vertebrae in thoracic metastatic spinal disease.
authors.affiliation: Department of Orthopaedics, University Medical Center Utrecht, Heidelberglaan 100, 3584CX, Utrecht, The Netherlands. j.j.verlaan@umcutrecht.nl
authors.forename: Jorrit-Jan
authors.initials: JJ
authors.lastname: Verlaan
authors.forename: Paulien G
authors.initials: PG
authors.lastname: Westhoff
authors.forename: Jochem
authors.initials: J
authors.lastname: Hes
authors.forename: Yvette M
authors.initials: YM
authors.lastname: van der Linden
authors.forename: René M
authors.initials: RM
authors.lastname: Castelein
authors.forename: F Cumhur
authors.initials: FC
authors.lastname: Oner
authors.forename: Marco
authors.initials: M
authors.lastname: van Vulpen
mesh_terms: D001859:Bone Neoplasms / Q000532:radiotherapy / Q000556:secondary; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D011183:Postoperative Complications / Q000517:prevention & control; D011829:Radiation Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal / Q000379:methods*; D013125:Spinal Neoplasms / Q000532:radiotherapy* / Q000556:secondary; D013904:Thoracic Vertebrae / Q000473:pathology / Q000528:radiation effects*; D014057:Tomography, X-Ray Computed