Radiation Exposure During Equine Radiography

Abstract

All personnel present in the X-ray examination room during equine radiography were monitored using low energy direct reading ionization chambers (pockets dosimeters) worn outside the lead apron at neck level. The individuals' task and dosimeter readings were recorded after each examination. Average doses ranged from 0 to 6 mrad per study. The greatest exposures were associated with radiography of the shoulder and averaged less than 4 mrad. The individual extending the horse's limb was at greatest risk although the individual holding the horse's halter and the one making the X-ray exposure received similar exposures.A survey of the overhead tube assembly used for some of the X-ray examinations also was performed. Meter readings obtained indicated an asymetric dose distribution around the tube assembly, with the highest dose occurring on the side to which the exposure cord was attached.Although the exposures observed were within acceptable limits for occupational workers, we have altered our protocol and no longer radiograph the equine shoulder unless the horse is anesthetized. Continued use of the pocket dosimeters and maintenance of a case record of radiation exposure appears to make the technologists more aware of radiation hazards.

Ultrasonography of the Equine Bicipital Tendon Region: A Case History Report and Review of Anatomy

“…* Due to the large size of the patient, quality radiographs of the equine shoulder are difficult to ~b t a i n .~ Additionally, a powerful radiographic machine is required, and potential radiation risk to personel is considerable . 6 General anesthesia has been suggested for animals over 350…”

Lack of radioprotection knowledge and compliance in Norwegian equine ambulatory practice

“…Radiographs of stifle, vertebral column, and shoulders require higher exposure factors compared to distal extremities due to increased surrounding soft tissue, and the result is increased scatter radiation, and hence, increased radiation exposure to the people who manage the generator or holding the image detector plate . In the present study, retakes of shoulder and stifles were 33% and 27%, respectively.…”

“…Image detector plate holders and stands for the radiography unit, which may help to increase the distance to the primary beam and scattered radiation, were used infrequently. Previous studies have shown that the distance to the primary beam and the origin of the scatter radiation is increased, the radiation dose to the person assisting in veterinary radiography is reduced . When the detector plate is handheld, there might also be an increased risk for exposure to the primary beam, which may cause higher radiation exposure …”

“…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.…”

ICRP Publication 153: Radiological Protection in Veterinary Practice

“…These simple measures lower patient dose and – by reducing radiation scatter generated in the exposed tissues and materials – improve image quality and reduce the exposure of professionally exposed persons as well as members of the public. (127) A prerequisite for optimisation is a thorough knowledge of the doses associated with a given exposure situation, as well as the factors that influence this dose. Reported doses per image to persons participating in radiographic examinations of small and large animals (Ackerman et al., 1988; Seifert et al, 2007; Hupe and Ankerhold, 2008 , 2011; Barber and McNulty, 2012; Eckert et al., 2015), or per examination for personnel present during standing CT examinations of the equine head (Dakin et al., 2014), fall in the range from 0.1 to 34 µSv. Doses towards the higher end of the range are typically encountered when thicker body parts are being radiographed, such as the abdomen in large dogs, or the equine head, spine (especially thoracic and lumbar regions), and proximal extremities.…”