title: Intraoperative detection of ¹⁸F-FDG-avid tissue sites using the increased probe counting efficiency of the K-alpha probe design and variance-based statistical analysis with the three-sigma criteria.
abstract: BACKGROUND
  Intraoperative detection of (18)F-FDG-avid tissue sites during 18F-FDG-directed surgery can be very challenging when utilizing gamma detection probes that rely on a fixed target-to-background (T/B) ratio (ratiometric threshold) for determination of probe positivity. The purpose of our study was to evaluate the counting efficiency and the success rate of in situ intraoperative detection of (18)F-FDG-avid tissue sites (using the three-sigma statistical threshold criteria method and the ratiometric threshold criteria method) for three different gamma detection probe systems.
  
  
  METHODS
  Of 58 patients undergoing (18)F-FDG-directed surgery for known or suspected malignancy using gamma detection probes, we identified nine (18)F-FDG-avid tissue sites (from amongst seven patients) that were seen on same-day preoperative diagnostic PET/CT imaging, and for which each (18)F-FDG-avid tissue site underwent attempted in situ intraoperative detection concurrently using three gamma detection probe systems (K-alpha probe, and two commercially-available PET-probe systems), and then were subsequently surgical excised.
  
  
  RESULTS
  The mean relative probe counting efficiency ratio was 6.9 (± 4.4, range 2.2-15.4) for the K-alpha probe, as compared to 1.5 (± 0.3, range 1.0-2.1) and 1.0 (± 0, range 1.0-1.0), respectively, for two commercially-available PET-probe systems (P < 0.001). Successful in situ intraoperative detection of 18F-FDG-avid tissue sites was more frequently accomplished with each of the three gamma detection probes tested by using the three-sigma statistical threshold criteria method than by using the ratiometric threshold criteria method, specifically with the three-sigma statistical threshold criteria method being significantly better than the ratiometric threshold criteria method for determining probe positivity for the K-alpha probe (P = 0.05).
  
  
  CONCLUSIONS
  Our results suggest that the improved probe counting efficiency of the K-alpha probe design used in conjunction with the three-sigma statistical threshold criteria method can allow for improved detection of 18F-FDG-avid tissue sites when a low in situ T/B ratio is encountered.
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute and Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus 43210, OH, USA. stephen.povoski@osumc.edu
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Povoski
authors.forename: Gregg J
authors.initials: GJ
authors.lastname: Chapman
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Murrey
authors.forename: Robert
authors.initials: R
authors.lastname: Lee
authors.forename: Edward W
authors.initials: EW
authors.lastname: Martin
authors.forename: Nathan C
authors.initials: NC
authors.lastname: Hall
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000601:surgery; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18