Many of the most commonly used medical imaging techniques involve the use of ionizing radiation. Patients, of course, must be protected from excessive exposure to radiation, but so do the radiologists, especially interventional radiologists who may be in charge of lengthy medical imaging procedures.
Computed tomography, or CT-guided interventions are becoming more common, and since radiologists are present in the exam room, they are vulnerable to radiation exposure. Factors affecting how much radiation radiologists are exposed to include the length and complexity of the procedure, and the position of the radiologist’s hands relative to the x-ray beam. For example, if a radiologist cannot reach a target lesion with an in-plane x-ray projection, how the gantry’s angle is positioned could expose the radiologist to more radiation. Risks to radiologists can be minimized, however, if certain best practices are adopted.
German Researchers: Low Exposure Risk if Precautions Taken
Researchers from University Medical Center Mannheim, of Heidelberg University recently published results of a study in the Journal of the American College of Radiology of radiation exposure to interventional radiologists during CT-guided interventions. The radiation exposure levels for staff don’t always correlate with the radiation doses to the patient; so patient dose is not a good determinant of personnel exposure. Shielding protocols are important for interventional radiologists, in order to minimize risk of overexposure to radiation during medical imaging.
In the study, radiologists wore thermoluminescent dosimieters on their foreheads, in front of their thyroids, on the chest, hands, feet, and inguinal area. Radiation doses were analyzed based on:
• Experience level of the interventional radiologist
• Difficulty of the procedure
• Lesion size
• Type of CT system used (dual-source versus multi-detector)
Radiologists also wore protective aprons of 0.35 mm or 0.5 mm lead equivalent, plus a thyroid collar. Measured doses were generally low. Ninety-six point seven percent of doses were below 100 microsieverts, 99.5% were below 500 microseiverts, and only 0.3% of doses exceeded 1,000 microsieverts. Fifty thousand microsieverts is the highest dose allowed in one year of occupational exposure.
Whole Body Dose vs. Extremities
The right hand was the site of most of the elevated doses, though most of these exposures were still less than 50 microsieverts. A median whole-body dose of 12 microsieverts was observed. Whole-body doses were significantly lower with the dual-source CT system versus the multi-detector system, except for forehead doses. Generally, the more complex the medical imaging procedure, the higher the radiologist’s exposure.
Best Practices During Interventional Radiology Procedures
The German study highlighted the importance of using best practices and protective measures during interventional radiology procedures. Image Gently, the alliance for radiation safety in pediatric imaging offers several best practices for interventional radiology procedures, and they include:
• Open communication among personnel and advanced planning of runs to minimize the need to repeat processes
• Lowering the number of exposures when possible
• Decreasing acquisitions and exposures if possible once an acceptable level of detail is obtained
• Positioning equipment with fluoroscopy off
• Using pulse fluoroscopy when possible, with a low pulse rate when possible
• Tight collimation of beams to decrease the area of exposure
• Using the lowest dose rate that provides acceptable image quality
• Minimizing electronic magnification
• Use of audible periodic fluoroscopy time alerts
• Limiting image acquisition to only those needed in terms of frames per second, lower dose protocols, magnification, and length of run
Safety of the patient and of the practitioner are critically important in interventional radiology. Interventional radiology is a highly specialized form of medical imaging, and the physicians who own and operate SteleRAD include interventional radiology specialists Dr. Nicholas Arfaras, Dr. Jon K. Guben, Dr. Joel Erickson, Dr. Linda Hughes, Dr. Michael B. Gordon and Dr. David Ring. SteleRAD‘s radiologists have extensive histories of excellence with interventional radiology, providing a broad range of interventional radiology services. To learn more about how SteleRAD can help your hospital, imaging center, or practice group, contact or call 954-358-5250.