Exposure from the large C-arm versus the mini C-arm using hand/wrist and elbow phantoms

J Hand Surg Am. 2011 Apr;36(4):628-31. doi: 10.1016/j.jhsa.2011.01.010.

Abstract

Purpose: 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.

Publication types

  • Comparative Study

MeSH terms

  • Elbow / radiation effects
  • Fluoroscopy / adverse effects
  • Fluoroscopy / instrumentation
  • Hand / radiation effects
  • Humans
  • Models, Biological
  • Phantoms, Imaging*
  • Radiation Dosage*
  • Radiation Injuries / prevention & control
  • Radiation Protection / methods*
  • Scattering, Radiation
  • Sensitivity and Specificity
  • Wrist / radiation effects