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Interventional Fluoroscopy: Reducing Radiation Risks for Patients and Staff

  • Posted: 04/18/2005

Determinants of radiation dose from interventional fluoroscopy

The radiation beam in interventional fluoroscopy procedures is typically directed at a relatively small patch of skin for a substantial length of time. This area of skin receives the highest radiation dose of any portion of the patient's body. The dose to this skin area may be high enough to cause a sunburn-like injury, hair loss, or in rare cases, skin necrosis (Mettler 2002). Threshold doses for potential radiation effects with related time of onset are presented below (ICRP 2000). The highest doses have been reported most frequently as a result of PTCA, radiofrequency cardiac ablation procedures, transjugular intrahepatic portosystemic shunts (TIPS) procedures and embolization procedures in the brain (Koenig 2001).

Appearance of radiation-induced skin injury approximately 18 to 21 months following multiple coronary angiography and angioplasty procedures - evidence of progressive tissue necrosisAppearance of radiation-induced skin injury approximately 18 to 21 months following multiple coronary angiography and angioplasty procedures - evidence of progressive tissue necrosis (Source: www.fda.gov/cdrh/rsnaii.html)

Potential Clinical Effects of Radiation Exposures to the Skin and Eye Lens

 EffectsThreshold dose (Gy)Time of onset
SkinEarly transient erythema22-24 hours
Main erythema reaction6~1.5 weeks
Temporary epilation3~3 weeks
Permanent epilation7~3 weeks
Dermal necrosis>12>52 weeks
EyeLens opacity (detectable)>1-2>5 years
Lens/cataract (debilitating)>5>5 years
Source: ICRP, 2000

During a procedure, several major parameters influence dose:

  • Number of images taken
  • Fluoroscopy time, field size and overlap of fields (Miller 2002)
  • Tube filtration, generator voltage and current
  • Reduced-dose pulsed fluoroscopy versus continuous fluoroscopy (Wagner 2000)
  • Distance between the X-ray tube and the patient and between the patient and the image receptor
  • Patient body habitus

Radiation dose is optimized when imaging is performed with the least amount of radiation required to provide adequate image quality and imaging guidance. Optimizing patient radiation dose also provides a direct benefit to the operator and assistants: scattered radiation in the room is directly proportional to the patient dose. If patient dose is reduced, so is the dose to the operator.