title: Coverage of anterior fossa in whole-brain irradiation.
abstract: OBJECTIVE
  Whole-brain irradiation is indispensable in the treatment of several brain tumors and requires coverage of the entire subarachnoid space. Retrospective studies have revealed frequent recurrences in the frontobasal fossa above the cribriform plate (CP). We sought to determine how accurately the latter could actually be identified on lateral radiographs such as those used for radiotherapy planning.
  
  
  METHODS
  The CP was localized by five radiation oncologists and five radiologists on lateral radiographs of 30 human skulls from an anatomic collection. Reference radiographs were acquired under identical conditions except for lead markers pointing to the CP and the ethmoid cells. The targeting accuracy was analyzed.
  
  
  RESULTS
  In 39% (n = 116), the location of the CP was correctly estimated within 2 mm. Mislocations of 2-5, 5-10, and >10 mm were noted in 34% (n = 102), 20% (n = 61), and 7% (n = 21), respectively. Neither specialty nor experience (years of training) exerted a significant influence on targeting accuracy. If the roofs of the ethmoid cells formed prominent bony edges, they were mistaken for the CP in 37%.
  
  
  CONCLUSIONS
  Lateral radiographs provide insufficient information to locate the CP accurately in whole brain irradiation. Additionally, localization was significantly impaired by prominent ethmoid cells.
authors.affiliation: Department of Radiation Oncology, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany. gripp@uni-duesseldorf.de
authors.forename: Stephan
authors.initials: S
authors.lastname: Gripp
authors.forename: Jörg
authors.initials: J
authors.lastname: Kambergs
authors.forename: Martin
authors.initials: M
authors.lastname: Wittkamp
authors.forename: Bärbel
authors.initials: B
authors.lastname: Gerlach
authors.forename: Andreas
authors.initials: A
authors.lastname: Saleh
authors.forename: Volkher
authors.initials: V
authors.lastname: Engelbrecht
authors.forename: Mathias
authors.initials: M
authors.lastname: Cohnen
authors.forename: Axel
authors.initials: A
authors.lastname: Scherer
authors.forename: Reinhardt
authors.initials: R
authors.lastname: Willers
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000532:radiotherapy*; D016371:Cranial Irradiation; D003951:Diagnostic Errors; D005004:Ethmoid Bone / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D006801:Humans; D008495:Medical Oncology / Q000592:standards; D011859:Radiography; D011871:Radiology / Q000592:standards