title: Radiation Dosimetry for Ureteroscopy Patients: A Phantom Study Comparing the Standard and Obese Patient Models.
abstract: OBJECTIVE
  To determine the effect of obesity on radiation exposure during simulated ureteroscopy.
  
  
  METHODS
  A validated anthropomorphic adult male phantom with a body mass index (BMI) of approximately 24 kg/m(2), was positioned to simulate ureteroscopy. Padding with radiographic characteristics of human fat was placed around the phantom to create an obese model with BMI of 30 kg/m(2). Metal oxide semiconductor field effect transistor (MOSFET) dosimeters were placed at 20 organ locations in both models to measure organ dosages. A portable C-arm was used to provide fluoroscopic x-ray radiation to simulate ureteroscopy. Organ dose rates were calculated by dividing organ dose by fluoroscopy time. Effective dose rate (EDR, mSv/sec) was calculated as the sum of organ dose rates multiplied by corresponding ICRP 103 tissue weighting factors.
  
  
  RESULTS
  The mean EDR was significantly increased during left ureteroscopy in the obese model at 0.0092 ± 0.0004 mSv/sec compared with 0.0041 ± 0.0003 mSv/sec in the nonobese model (P < 0.01), as well as during right ureteroscopy at 0.0061 ± 0.0002 and 0.0036 ± 0.0007 mSv/sec in the obese and nonobese model, respectively (P < 0.01). EDR during left ureteroscopy was significantly greater than right ureteroscopy in the obese model (P = 0.02).
  
  
  CONCLUSIONS
  Fluoroscopy during ureteroscopy contributes to the overall radiation dose for patients being treated for nephrolithiasis. Obese patients are at even higher risk because of increased exposure rates during fluoroscopy. Every effort should be made to minimize the amount of fluoroscopy used during ureteroscopy, especially with obese patients.
authors.affiliation: 1 Comprehensive Kidney Stone Center, Duke University Medical Center , Durham, North Carolina.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Shin
authors.affiliation: 1 Comprehensive Kidney Stone Center, Duke University Medical Center , Durham, North Carolina.
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Cabrera
authors.affiliation: 2 Radiation Safety Division, Duke University Medical Center , Durham, North Carolina.|6 Department of Radiology, Duke University , Durham, North Carolina.
authors.forename: Giao
authors.initials: G
authors.lastname: Nguyen
authors.affiliation: 2 Radiation Safety Division, Duke University Medical Center , Durham, North Carolina.|5 Graduate Program of Medical Physics, Duke University , Durham, North Carolina.
authors.forename: Chu
authors.initials: C
authors.lastname: Wang
authors.affiliation: 3 Urology Department, University of California , Irvine, Orange, California.
authors.forename: Ramy F
authors.initials: RF
authors.lastname: Youssef
authors.affiliation: 1 Comprehensive Kidney Stone Center, Duke University Medical Center , Durham, North Carolina.|4 Duke Clinical Research Institute, Duke University , Durham, North Carolina.
authors.forename: Charles D
authors.initials: CD
authors.lastname: Scales
authors.affiliation: 1 Comprehensive Kidney Stone Center, Duke University Medical Center , Durham, North Carolina.
authors.forename: Michael N
authors.initials: MN
authors.lastname: Ferrandino
authors.affiliation: 1 Comprehensive Kidney Stone Center, Duke University Medical Center , Durham, North Carolina.
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Preminger
authors.affiliation: 2 Radiation Safety Division, Duke University Medical Center , Durham, North Carolina.|6 Department of Radiology, Duke University , Durham, North Carolina.|7 Department of Radiation Oncology, Duke University , Durham, North Carolina.
authors.forename: Terry T
authors.initials: TT
authors.lastname: Yoshizumi
authors.affiliation: 1 Comprehensive Kidney Stone Center, Duke University Medical Center , Durham, North Carolina.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Lipkin
mesh_terms: D000328:Adult; D015992:Body Mass Index; D001835:Body Weight; D005471:Fluoroscopy / Q000379:methods*; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D053040:Nephrolithiasis / Q000601:surgery*; D009765:Obesity; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D000069079:Radiation Exposure / Q000706:statistics & numerical data*; D011874:Radiometry; D018666:Ureteroscopy / Q000379:methods*