A U G U S T 2 0 1 5 O U T P A T I E N TS U R G E R Y. N E T 3 5
Plus, a mini C-arm saves you the expense of acquiring additional imaging
equipment. In order to fluoroscopically image a patient on a table with a full-
sized C-arm, that table has to be constructed from radiolucent materials. With
a mini C-arm, your OR team can use the surgical table you already have. By
inverting the arm (which is draped for use in the sterile field), they can use the
image intensifier as the operating surface for the hand, foot or ankle.
Incidentally, this inverted-position use has also been found to reduce radiation
exposure to the patient and the surgeon (osmag.net/joR7EM).
If you see your surgeons doing a lot of mini-C-arm-suitable cases, then by all
means go with the compact unit. At $50,000 or under, a mini C-arm is less
expensive and does an equally good job to a full-sized unit. But obtaining a larg-
er unit that's able to serve multiple purposes can attract surgeons in other disci-
plines.
2. Imaging and control
Newer C-arm models incorporate special imaging functions that not only
improve the surgical view, but provide a measure of safety for the surgical team
and patient. "As Low As Reasonably Achievable" (ALARA) is the guiding princi-
ple for the safe use of C-arms and other imaging equipment (see "How Safe Are
Your Imaging Practices?" on p. 22). Your surgeons want high-quality images,
but you need to limit the amount of radiation exposure in the process. "Coning
down" is an automated function available on newer machines that reduces the
radiation dose without adversely affecting the resulting image. It focuses the
beam to minimize the area exposed to radiation (to protect the patient) and
decrease the amount of radiation scattered (to protect the staff).
It's called "coning down" because traditionally it has worked as a shrinking
circle, like a camera lens or the eye's iris. Some newer C-arms, however, can
"cone in" by cropping the image vertically from the left and right sides
toward the midline of the view, creating a narrow rectangular image. This can
