Page 228 - Adams and Stashak's Lameness in Horses, 7th Edition

194 Chapter 3

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Figure 3.4. Acquisition of 60° dorsoproximal to palmarodistal
oblique using a Redden navicular block.

RADIATION SAFETY
The general principles of radiation safety are as
follows:
1. Keeping personnel as far away from the radiation
source (X‐ray tube) as possible
2. Using protective barriers
3. Reducing X‐ray exposure factors Figure 3.5. Radiograph of a lead glove, showing a lucent area
4. Using a radiation‐monitoring system (arrows) that represents a defect or hole in the lead lining.
Keeping personnel as far away from the X‐ray source hanging them when they are not in use. This prevents
as possible can be accomplished by having nonessential cracks or holes forming in the lead‐impregnated lining
personnel leave the immediate area, using cassette hold­ as a result of improper care. All lead PPE should be radi­
ers and positioning blocks, providing tranquilization or ographed periodically to check for damage (Figure 3.5).
general anesthesia when needed, using an X‐ray tube An X‐ray beam‐limiting device or collimator
1
stand or support, and having a 1‐ to 2‐meter‐long cord (Figure 3.2) is an important, yet overlooked, piece of
connected to the exposure button. No part of the body radiation safety equipment. The size of the primary
should be exposed to the primary X‐ray beam. X‐ray beam is a major factor in determining radiation
The personnel subject to the greatest exposure when dose to the hands. Adjustable light‐beam collimators
performing equine examinations are those holding the have the advantage of limiting the primary X‐ray beam
horse’s limb, the detector holder, and those holding the to the exact cassette size, regardless of the FFD. The light
halter. Therefore, if personnel must be near the animal also assists alignment of the primary X‐ray beam with
1
when the X‐ray examination is performed, they should the cassette. Every X‐ray machine should have an adjust­
wear lead personal protective equipment (PPE). able beam‐limiting device.
A radiation‐monitoring system should be used by all In summary, the following safety measures should be
radiology personnel. These systems not only provide observed:
safety guidance but also protect against possible legal
implications. Film‐badge monitoring systems and ser­ • Never handhold the X‐ray detector during an expo­
vice can be purchased from commercial sources. sure. Detector holders or handles should be used.
Equipment necessary for safely operating an X‐ray • All personnel not needed for assistance with the X‐ray
machine includes detector holders, lead PPE, aluminum examination should leave the immediate area.
filters, and an adjustable light‐beam collimator. Detector • Lead gloves, thyroid shields, and aprons should be
holders eliminate the need to handhold detectors, worn by all individuals assisting with the X‐ray
increasing the distance between hands and the X‐ray examination.
beam. • A primary X‐ray beam‐restricting device should be
Lead aprons, thyroid shields, and gloves should be used, preferably an adjustable light‐beam collimator.
worn by everyone assisting with the X‐ray examination. • If possible, rotate personnel responsible for holding
Protective gear should have at least 0.5‐mm lead equiva­ the detector; avoid routinely using the same person
lent. Lead PPE provides adequate protection from sec­ for this job.
ondary and scattered radiation but not from primary • Do not allow anyone under 18 years of age to assist
radiation. The life of lead PPE can be prolonged by with an X‐ray examination.