title: Radiation Exposure during the Evaluation and Management of Nephrolithiasis.
abstract: OBJECTIVE
  There is rising concern over the increasing amount of patient radiation exposure from diagnostic imaging and medical procedures. Patients with nephrolithiasis are at potentially significant risk for radiation exposure due to the need for imaging to manage recurrent stone disease. We reviewed the literature in an attempt to better characterize actual risks and discussed methods to reduce radiation exposure for adult patients with nephrolithiasis.
  
  
  METHODS
  A PubMed search was performed using the key words nephrolithiasis, stones, radiation, fluoroscopy, ureteroscopy, percutaneous nephrolithotomy, computerized tomography and shock wave lithotripsy. Additional citations were identified by reviewing reference lists of pertinent articles.
  
  
  RESULTS
  A total of 50 relevant articles were included in this review. Patients with a first time acute stone event are exposed to a significant amount of radiation. Most radiation is from computerized tomography. Patients undergoing percutaneous nephrolithotomy are exposed to an equal or greater amount of radiation than they received from computerized tomography. Risk factors for increased exposure during percutaneous nephrolithotomy include obesity, multiple tracts and a larger stone burden. Ureteroscopy exposes patients to approximately the same amount of radiation as plain x-ray of the kidneys, ureters and bladder. Risk factors for increased exposure during ureteroscopy include obesity and ureteral dilation. During shock wave lithotripsy the amount of radiation exposure is not well characterized. Interventions to reduce exposure to patients include using ultrasound when possible and implementing low dose computerized tomography protocols. The as low as reasonably achievable principle of radiation exposure should always be followed when fluoroscopy is performed. The use of an air retrograde pyelogram may also reduce exposure during percutaneous nephrolithotomy. Fluoroscopy time during ureteroscopy may be decreased by a laser guided C-arm, a dedicated C-arm technician, stent placement under direct vision and tactile feedback to help guide wire placement.
  
  
  CONCLUSIONS
  Patients with nephrolithiasis are at significant risk for increased radiation exposure from the imaging and fluoroscopy used during treatment. The true risks of low radiation exposure remain uncertain. It is important to be aware of these risks to provide better counseling for patients. Urologists must also be familiar with techniques to decrease radiation exposure for patients with nephrolithiasis.
authors.affiliation: School of Medicine, Duke University Medical Center, Durham, North Carolina.
authors.forename: Tony T
authors.initials: TT
authors.lastname: Chen
authors.affiliation: Division of Radiation Safety, Duke University Medical Center, Durham, North Carolina.
authors.forename: Chu
authors.initials: C
authors.lastname: Wang
authors.affiliation: Division of Urology, Department of Surgery, Duke University Medical Center, Durham, North Carolina.
authors.forename: Michael N
authors.initials: MN
authors.lastname: Ferrandino
authors.affiliation: Division of Urology, Department of Surgery, Duke University Medical Center, Durham, North Carolina.
authors.forename: Charles D
authors.initials: CD
authors.lastname: Scales
authors.affiliation: Division of Radiation Safety, Duke University Medical Center, Durham, North Carolina; Department of Radiology, Duke University Medical Center, Durham, North Carolina; Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina.
authors.forename: Terry T
authors.initials: TT
authors.lastname: Yoshizumi
authors.affiliation: Division of Urology, Department of Surgery, Duke University Medical Center, Durham, North Carolina.
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Preminger
authors.affiliation: Division of Urology, Department of Surgery, Duke University Medical Center, Durham, North Carolina. Electronic address: michael.lipkin@duke.edu.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Lipkin
mesh_terms: D003952:Diagnostic Imaging / Q000009:adverse effects; D006801:Humans; D053040:Nephrolithiasis / Q000175:diagnosis* / Q000628:therapy*; D011829:Radiation Dosage; D000069079:Radiation Exposure / Q000517:prevention & control; D014057:Tomography, X-Ray Computed / Q000009:adverse effects
keywords: diagnostic imaging; fluoroscopy; kidney; nephrolithiasis; radiation dosage