Commonsense approach protects patients and staff in interventional suite

November 25, 2007

Practitioners can minimize radiation exposure during interventional procedures by following 10 easy steps, according to Dr. Navnit Kumar, a radiologist from Leeds Teaching Hospitals in the U.K.

Practitioners can minimize radiation exposure during interventional procedures by following 10 easy steps, according to Dr. Navnit Kumar, a radiologist from Leeds Teaching Hospitals in the U.K.

Kumar provided a checklist in an education exhibit at the RSNA congress:

  • Ask yourself if the examination is really necessary and if an alternative is safer or more effective. For instance, most diagnostic digital subtraction angiograms can now be achieved with CT angiography or MRA.
  • Conduct a thorough review of previous imaging procedures. In patients with gastrointestinal bleeding, looking at the patient's history and endoscopy results can help you target the site rather than perform generalized examinations. This reduces radiation dose for the patient and staff.
  • Make full use of shielding. Aprons should be 0.35 to 0.70 lead equivalent. Use eye, thyroid, and hanging face shields, as well as undercouch lead skirts. Avoid placing hands in the primary beam and wear lead gloves if necessary. Finally, stand on the side of the image intensifier.
  • Increase distance between staff and equipment. Doubling the distance between the operator and primary beam reduces the exposure by a factor of four. Use long connectors and ensure staff are as far away from the equipment as practical. Oblique views and steep angulations increase radiation exposure by bringing the x-ray tube closer, and the operator should reposition on the image intensifier side.
  • Minimize radiation exposure time. Minimize "beam on" time by preplanning images and the procedure, review the previous imaging (decide on best views), communicate to the team, and introduce "dry run" procedures, especially in nonroutine and complex cases. Use minimal intermittent fluoroscopy for patient positioning and use last image hold feature for viewing static images rather than continuous fluoroscopy. During the procedure, the operator must be aware of fluoroscopy time and radiation dose. The frame rate should be as low as reasonably possible, and you should watch for the positioning of the device during guidewire/catheter exchange.
  • Use screen grabs when lower anatomic detail is acceptable. The fluoroscopy dosage per frame of screen grabs is substantially lower than acquisition.
  • Reduce magnification, which increases radiation exposure. Use digital magnification zoom facility or minimum focused magnification view after deciding on appropriate projections. Do not survey with magnified views and do not magnify using increased patient-to-intensifier distance because this increases secondary radiation.
  • Tighter collimation reduces scatter radiation and therefore cuts patient and operator dose. Improve image quality by reducing image noise due to scatter radiation originating from outside the region of interest.
  • Road map image allows review of anatomy without the need for reacquisition. Perform only road map images rather than a full DSA in patients undergoing peripheral angioplasty, after having a good diagnostic MR or CT angiogram.
  • Reduce the number of people in the angiography suite. When not directly assisting, supporting staff/observers should stay as far away as possible and behind the shield.