Members of your surgical team are at risk every time C-arms are switched on from a danger they can't see or feel. Luckily, the steps they can take to protect themselves from X-ray scatter are rooted in common sense. My role as a radiation safety officer at a large hospital lets me track the amount of radiation thousands of surgical professionals are exposed to each year, and most have little to extremely low levels of exposure because they work with the latest imaging technologies, practice proper fluoroscopy techniques and understand the 3 fundamentals of radiation safety.

ALARA ("as low as reasonably achievable") is the guiding principle of radiation practices: use the lowest possible dose to obtain needed images. That can be achieved by keeping the beam-on time to an absolute minimum. The Golden Rule is to reduce fluoroscopy doses to the minimum necessary to achieve the clinical result.

Several features on newer machines help you achieve that aim:

• Pulsed fluoroscopy delivers radiation in short bursts, instead of continuously, to capture images.
• Loop functions cycle through a series of captured images, letting the physician review what has been captured to decide if he can avoid reactivating the C-arm to capture useful images.
• Last-image hold features freeze the image that's captured as soon as the C-arm is deactivated. This mode can be used in place of live fluoroscopy to confirm anatomical information and the locations of hardware and implants.

Remember, doses accumulate as exposure time increases. Relying on these features found on new C-arms and a judicious use of fluoroscopy will limit the amount of time the C-arm is activated.

Every member of the surgical team should wear lead aprons, which protect wearers against 95% of radiation scatter. Staff members who need to be adjacent to the OR table should also wear thyroid shields and leaded glasses. Eye and thyroid protection are optional for staffers in the room who generally are more than 6 feet away from the table.

The annual allowable radiation exposure is 50 millisieverts. The ALARA Level 1 threshold is 5 millisieverts — 10% of the annual limit. That's the pay-attention threshold. The ALARA Level 2 threshold is 15 millisieverts, or 30% of the annual limit. That's the investigational threshold where you're going to have to find out what your team has been doing to get that kind of exposure, which shouldn't be happening if they've been following good safety practices.

Here at Yale New Haven Hospital, which has thousands of operating room staff members, we give radiation dosimeters — which measure exposure levels — to only about 1,000 workers, the ones who we think are most likely to have radiation exposure of any significance. Smaller hospitals and freestanding ambulatory surgery centers don't have professional health physics experts on staff, so they often give dosimeters (also called film badges) to all members of the clinical team.

Dosimeters are retrospective tools that allow you to assess the effectiveness of your radiation safety program. If you're following good practice, the vast majority of your employees won't be getting exposed to high amounts of radiation, so the results from the dosimeters should be negligible. In lieu of having professionals on hand to determine who needs these devices, it's easier to badge everyone who works imaging cases.

Maintain perspective

We're all exposed to about 3 millisieverts of natural radiation each year. The effective dose of a chest CT is about 5 millisieverts, which is equivalent to about a year and change of our natural exposure. Yes, you're working with radiation, but if you understand the fundamentals of time, distance and shielding, you can easily keep your occupational exposure well within the variation we're exposed to by simply walking outside. OSM