title: MRI-assisted cervix cancer brachytherapy pre-planning, based on application in paracervical anaesthesia: final report.
abstract: BACKGROUND
  Optimal applicator insertion is a precondition for the success of cervix cancer brachytherapy (BT). We aimed to assess feasibility and efficacy of MRI-assisted pre-planning, based on applicator insertion in para-cervical anaesthesia (PCA).
  
  
  METHODS
  Five days prior to BT, the pre-planning procedure was performed in 18 cervix cancer patients: tandem-ring applicator was inserted under PCA, pelvic MRI obtained and applicator removed. Procedure tolerability was assessed. High risk clinical target volume (HR CTV) and organs at risk were delineated on the pre-planning MRI, virtual needles placed at optimal positions, and dose planning performed. At BT, insertion was carried out in subarachnoidal anaesthesia according to pre-planned geometry. Pre-planned and actual treatment parameters were compared.
  
  
  RESULTS
  Pre-planning procedure was well tolerated. Median difference between the pre-planned and actual needle insertion depth and position were 2 (0-10) mm and 4 (0-30) degrees, respectively. The differences between the pre-planned and actual geometric and dosimetric parameters were statistically non-significant. All actual needles were positioned inside the HR CTV and outside the organs at risk (OAR).
  
  
  CONCLUSIONS
  Our pre-planning approach is well tolerated and effective. Pre-planned geometry and dose distribution can be reproduced at BT.
authors.affiliation: Department of Radiation Oncology, National Center for Cancer Care and Research, Doha, Qatar ; Department of Radiotherapy, Institute of Oncology Ljubljana, Ljubljana, Slovenia.
authors.forename: Primoz
authors.initials: P
authors.lastname: Petric
authors.affiliation: Department of Radiotherapy, Institute of Oncology Ljubljana, Ljubljana, Slovenia.
authors.forename: Robert
authors.initials: R
authors.lastname: Hudej
authors.affiliation: Department of Radiotherapy, Institute of Oncology Ljubljana, Ljubljana, Slovenia.
authors.forename: Omar
authors.initials: O
authors.lastname: Hanuna
authors.affiliation: Department of Radiotherapy, Institute of Oncology Ljubljana, Ljubljana, Slovenia.
authors.forename: Primoz
authors.initials: P
authors.lastname: Marolt
authors.affiliation: Department of Radiation Oncology, National Center for Cancer Care and Research, Doha, Qatar.
authors.forename: Noora Mohammed A A
authors.initials: NM
authors.lastname: Al-Hammadi
authors.affiliation: Department of Radiation Oncology, National Center for Cancer Care and Research, Doha, Qatar.
authors.forename: Mohamed P
authors.initials: MP
authors.lastname: Riyas
authors.affiliation: Department of Radiotherapy, Institute of Oncology Ljubljana, Ljubljana, Slovenia.
authors.forename: Barbara
authors.initials: B
authors.lastname: Segedin
keywords: MRI; cervix cancer; image-guided brachytherapy; pre-planning