Fluoroscopy and Radiation

An estimated 4-10 million interventional pain procedures are performed annually in the United States, where at least 50% of those are performed under fluoroscopy. The major purpose of fluoroscopy is for correct needle placement to ensure target specificity and accurate delivery of the injected drug. However, this interventional technique of fluoroscopic guidance does result in radiation exposure with risks posed to patients, physicians, and other personnel. Federal regulations do limit the maximum output for C-Arms, and there are a range of techniques to reduce the risk in private practice settings.

Radiation Exposure

Fear over patient radiation doses is a valid concern. Nonetheless, it is important to understand that the goal of all interventional radiology procedures is to treat (not harm) patients and improve their well-being. As a physician, radiation risks associated with interventional procedures should be discussed with patients, particularly when the expected dose of radiation may be high.

In general, fluoroscopy delivers a dose of approximately 5 rads per minute in the direct beam. The thickness of the patient also determines the exposure rate: the thicker the patient, the higher the exposure. Even small doses of radiation (1 rad = approximately one chance in 100,000) can damage DNA, which can essentially cause acute health effects.

Since shielding the patient is not usually possible, time and distance are key in helping reducing their exposure. Time: shorter fluoro times can be achieved when the physician uses intermittent fluoroscopy (as opposed to continuous), and utilizes the image hold capacity. Distance: the patient’s exposure increases exponentially the closer he/she is positioned to the x-ray tube. Positioning the patient as far as possible from the x-ray tube (maybe 12 to 15 inches away from body) and as close to possible to the image intensifier can reduce exposure. (Decreasing x-ray field size can also reduce patient exposure).

With C-Arms, education is a must for properly monitoring and reducing exposure levels for patients and staff. Receive training from a qualified expert (radiologist or radiological health physicist) in safety procedures and proper imaging techniques. Good safety practices, such as the ones below, can also keep radiation doses As Low As Reasonably Achievable (ALARA).

Radiation Safety

Time, distance, and shielding are the three basic guides that could and should be taken for radiation safety. First and foremost, do not allow any unauthorized visitors during x-ray exams. Only individuals required for the radiographic procedure should be present in the radiographic room during exposures.

Timing. As we mentioned before, with timing, shorter fluoro times can be achieved when the physician uses intermittent fluoroscopy. Also, analyze original radiographs before performing a fluoroscopic examination. Viewing original radiographs, especially for orthopedic studies, can dramatically reduce the repeat rate for the time required for procedures.

Distance. Observers should stand on the image intensifier side of the C-arm if possible, to avoid radiation leakage from the x-ray tube. When not assisting, step away from the patient during fluoro, as feasible. Stepping even one foot further back can significantly reduce a person’s dose.