Estimated Operator Exposure for Hand Holding Portable X‐ray Units During Imaging of the Equine Distal Extremity

Abstract

Hand holding of portable X-ray units is common in large animal ambulatory veterinary practice. Portable X-ray equipment manuals, veterinary teaching institutions, and state regulations discourage, or prohibit, hand holding of portable X-ray units. Our goal was to quantify surface radiation leakage of a typical portable X-ray unit and to measure operator exposure at simulated hand and collar positions during imaging of the equine distal extremity. Each exposure for the study was performed at 80 kVp and 7.5 mAs and repeated 10 times. Measurement of tube radiation leakage was performed along each surface of the portable X-ray unit. To determine the operator exposure more accurately, an equine cadaver limb was used to generate scatter radiation for the following views: lateral carpus, lateral foot, palmaroproximal-palmarodistal, and dorsal 60° proximal-palmarodistal obliques of the navicular region. A Pancake Ion Chamber was placed at the handle and at simulated collar position to record estimated occupational exposure. To estimate the effect of lead shielding, exposure measurements were performed within the primary beam and behind a 0.5 mm lead equivalent apron and within an >0.5 mm lead equivalent glove. The average hand and collar dose was 0.471 and 0.327 mR/exposure, respectively. The lead apron and glove attenuated the primary beam 96.9 and 99.2%, respectively. This reduced average hand and collar exposures to 0.0038 and 0.0101 mR/exposure, respectively. Theoretical occupational limits are reached for the collar (whole body) before the hand (extremity).

EVALUATION OF TWO OBJECTIVE METHODS TO OPTIMIZE KVP AND PERSONNEL EXPOSURE USING A DIGITAL INDIRECT FLAT PANEL DETECTOR AND SIMULATED VETERINARY PATIENTS

“…Similar to our results, it was concluded that personnel dose was extremely low, in the range of 2–49 microsievert. In this range, personnel exposure would not be expected to exceed the annual occupational dose for adults of 0.5 sievert set forth by the institution's state Radiation Protection Commission, especially when compared to a recent study of operator exposure during hand holding of portable x‐ray units for equine imaging . In conclusion, by incorporating the principles of ALARA into technique optimization using an objective endpoint, a single technique is not appropriate for all imaging studies of small animal patients.…”

Lack of radioprotection knowledge and compliance in Norwegian equine ambulatory practice

“…The veterinarians were mainly managing the generator, while the horse owners or other handlers mainly were holding the image detector plate, which is in agreement with what was found in other European countries . Previous studies have shown that the person that is closest to the primary beam and the origin of the scattered radiation receives the highest radiation exposures . This position is most often filled by non‐members of staff who lack knowledge of radiation protection.…”

Common artefacts and pitfalls in equine computed and digital radiography and how to avoid them

“…Hand holding of generators not only increases the risk of motion blur, but also should be avoided because of the resulting radiation exposure to the person holding it (Tyson et al . ). Patient motion is especially common in poorly sedated, neurologically abnormal or fractious horses, and ensuring that the patient is appropriately restrained is vital to obtaining high‐quality images.…”

“…Motion of the x-ray generator can be secondary to a pendulum effect when the generator is suspended from the ceiling or a stand; it is important to stabilise the generator to stop this motion prior to image acquisition. Hand holding of generators not only increases the risk of motion blur, but also should be avoided because of the resulting radiation exposure to the person holding it (Tyson et al 2011). Patient motion is especially common in poorly sedated, neurologically abnormal or fractious horses, and ensuring that the patient is appropriately restrained is vital to obtaining high-quality images.…”