title: Exposure from the large C-arm versus the mini C-arm using hand/wrist and elbow phantoms.
abstract: OBJECTIVE
  This study tests the conventional wisdom that using fluoroscopy under identical geometrical conditions results in less radiation when using the mini C-arm relative to the large C-arm.
  
  
  METHODS
  We evaluated the radiation dose for both direct exposure and scatter 2.54 cm outside the intensifier. We used 3 mini and 3 large C-arms in a vertical orientation with the image intensifier below the specimen and the source above. We used 2 specimens: a cadaver hand/wrist and a cadaver elbow. Specimens were tested both directly on the intensifier and on a hand table placed on the intensifier.
  
  
  RESULTS
  For the same setup, use of the mini C-arm resulted in direct patient radiation exposure greater than the exposure delivered by the large C-arm. Specifically, exposure using the mini C-arm was 53% to 70% greater than that using the large C-arm. In addition, use of the hand table resulted in exposure 80% to 94% greater compared with placing the specimen directly on the intensifier. In all cases, scatter at 2.54 cm from the intensifier resulted in an average exposure of 1.5% (SD, 0.24%) of the direct beam. Tube current, and therefore machine radiation output, was approximately 13 to 14 times greater for the large C-arm.
  
  
  CONCLUSIONS
  Direct radiation exposure to the patient and scatter to the surgeon are minimized when the C-arm is positioned with the intensifier below and the extremity is placed directly on the intensifier. Under identical geometrical conditions with the intensifier below the specimen, the large C-arm with its greater source to image intensifier distance is associated with less radiation exposure than the mini C-arm.
authors.affiliation: Department of Orthopaedic Surgery, Hadassah Medical Organization, Jerusalem, Israel. gershonzinger@gmail.com
authors.forename: Gordon
authors.initials: G
authors.lastname: Singer
authors.forename: Brent
authors.initials: B
authors.lastname: Herron
authors.forename: David
authors.initials: D
authors.lastname: Herron
mesh_terms: D004550:Elbow / Q000528:radiation effects; D005471:Fluoroscopy / Q000009:adverse effects / Q000295:instrumentation; D006225:Hand / Q000528:radiation effects; D006801:Humans; D008954:Models, Biological; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000517:prevention & control; D011835:Radiation Protection / Q000379:methods*; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D014953:Wrist / Q000528:radiation effects