title: Radiation dosimetry of intraoperative cone-beam compared with conventional CT for radiofrequency ablation of osteoid osteoma.
abstract: BACKGROUND
  Radiofrequency (RF) ablation is the standard of care for the surgical treatment of non-spinal osteoid osteoma and has greatly reduced morbidity associated with surgical excision. Precise placement of the RF ablation probe is necessary to avoid incomplete ablation. Limiting radiation exposure is especially advantageous in the pediatric population in whom osteoid osteoma frequently occurs. The aim of this study was to compare the radiation dosimetry and clinical outcomes among patients treated with RF ablation using three different localization techniques.
  
  
  METHODS
  Case-control methods were used to analyze sixty-six cases. Patients were categorized into three treatment groups: (1) intraoperative three-dimensional cone-beam CT (computed tomography) imaging (O-Arm) with surgical navigation (StealthStation S7), (2) intraoperative three-dimensional imaging (O-Arm) only, and (3) radiology suite-based diagnostic CT imaging. Radiation dosimetry and clinical outcome were analyzed with use of the dose-length product and local-relapse-free survival, respectively.
  
  
  RESULTS
  Mean age was nineteen years for the twenty-three patients in group 1, twenty years for the seven patients in group 2, and nineteen years for the thirty-six patients in group 3. Mean follow-up was fifty-three months. The mean radiation dose for groups 1, 2, and 3 was 446.62, 379.78, and 1058.83 mGy-cm, respectively. Significant (p < 0.05) differences in the radiation dose existed between groups 1 and 3 and between groups 2 and 3, whereas no difference was found between groups 1 and 2. Local-remission-free survival at three years for groups 1, 2, and 3 was 84.7% (95% confidence interval [CI], 64.5% to 100%), 100% (95% CI, 100% to 100%), and 90.7% (95% CI, 80.7% to 100%), respectively. Fifty-eight (92%) of the sixty-three followed patients were asymptomatic at the latest follow-up visit.
  
  
  CONCLUSIONS
  RF ablation using intraoperative cone-beam CT imaging, with or without surgical navigation, was associated with a significantly lower radiation dose compared with ablation using a radiology suite-based CT technique. Ablation using each of the three imaging techniques was equally effective in treating osteoid osteomas with a similar risk of relapse.
authors.affiliation: Department of Orthopaedic Surgery, University of Minnesota, 2512 South 7th Street, R200, Minneapolis, MN 55454. E-mail address for E.Y. Cheng: cheng002@umn.edu. E-mail address for S.M. Naranje: sameernaranje@gmail.com.
authors.forename: Edward Y
authors.initials: EY
authors.lastname: Cheng
authors.affiliation: Department of Orthopaedic Surgery, University of Minnesota, 2512 South 7th Street, R200, Minneapolis, MN 55454. E-mail address for E.Y. Cheng: cheng002@umn.edu. E-mail address for S.M. Naranje: sameernaranje@gmail.com.
authors.forename: Sameer M
authors.initials: SM
authors.lastname: Naranje
authors.affiliation: Department of Diagnostic Radiology, University of Minnesota, MMC 292, Room B-275 Mayo, 420 Delaware Street S.E., Minneapolis, MN 55455. E-mail address: riten001@umn.edu.
authors.forename: E Russell
authors.initials: ER
authors.lastname: Ritenour
mesh_terms: D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D001864:Bone Wires; D016022:Case-Control Studies; D017115:Catheter Ablation / Q000379:methods*; D054893:Cone-Beam Computed Tomography; D018572:Disease-Free Survival; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007430:Intraoperative Care / Q000379:methods; D008297:Male; D059352:Musculoskeletal Pain / Q000517:prevention & control; D010017:Osteoma, Osteoid / Q000000981:diagnostic imaging / Q000601:surgery*; D011829:Radiation Dosage; D015641:Radiography, Interventional; D011874:Radiometry; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult