as tube voltage (kV) and pulse time to ensure the smallest possible
radiation dose is delivered.
Collimate the C-arm's beams to focus on the targeted area,
reduce exposure to adjacent tissue and limit the potential for
scatter. Start with the collimators closed and gradually open them
until only the desired imaging area is in view. Newer machines let
you adjust the collimation without activating the fluoroscopy,
which is a nice safety feature. Use the last-image-hold feature
available on newer machines to study specific anatomy instead of
delivering constant fluoroscopy to capture continuous images.
Only activate the unit when your attention is on the monitor.
Communication between surgeons and techs helps ensure the flu-
oroscopy is activated only when intended.
Layers of protection
It's essential to place a protective shield over areas of the body
that have a high rate of rapidly dividing cells, such as the thyroid
and gonads, where ionizing radiation mutates the body's DNA.
Cataracts can be caused by long-term exposure to ionized radia-
tion, but lead-lined glasses with side shields decrease exposure by
more than 90%. According to the ICRP, aprons of 0.25-mm lead
equivalence suffice for procedures performed on pediatric
patients and thin individuals, and 0.35-mm lead equivalence offer
protection needed for surgeries performed on thick patients or
for surgeons and staff who work many imaging procedures. Opt
for wrap-around aprons, which provide back-and-front protection.
Still, never turn your back on the surgical field when the X-ray is
activated.
Lead gowns of at least 0.5-mm thickness reduce exposure to
scatter by 90%, says the ICRP, but only if they're properly main-
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