ments, to store them properly after use, than aprons taken from the
general stock."
Dr. Kaplan and his colleagues in the OR wear a dosimeter badge on
the thyroid shield and another on the inside of the protective vest,
against the chest, to measure their levels of radiation exposure. The
maximum annual dose surgical team members should be exposed to
is 20 mSv for the body. The annual threshold is higher for the thyroid
and eyes (150 mSv), and hands (500 mSv). Each month, monitor and
document individual dosimeter readings to ensure team members
remain under the annual threshold of acceptable exposure to radia-
tion.
Less is more
The ALARA principle — maintaining radiation doses "as low as reason-
ably achievable" when capturing intraoperative images — should guide
C-arm use in the OR. So should the inverse square law, which states
the magnitude of exposure to radiation scatter is inversely proportion-
ate to the distance from the source. Per the law, doubling the distance
from the X-ray tube reduces your exposure to scatter by one-fourth.
Mindful that most radiation scatter occurs between the X-ray tube
and the patient, Dr. Kaplan offers this advice:
• Position the tube underneath the table to limit scatter — and to
deflect scatter that does occur toward the legs and feet, not the head
and neck, of the OR team.
• Position the image intensifier as close as possible to the patient to
limit the distance radiation travels between it and the X-ray tube, and
to also widen the field of view.
• When you position the C-arm horizontally to capture lateral views
of anatomy, stand on the side of the table opposite the X-ray tube.
To further limit exposure, use low-dose fluoroscopy — pulsed
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