Radiation exposure during simulated equine head and limb fan beam standing computed tomography appears safe for personnel using lead shielding.

Overview

• This study measured radiation exposure to veterinary personnel during simulated equine head and limb scans using a novel standing computed tomography (CT) system designed for horses.
• The research aimed to determine whether radiation doses remained safe for operators and handlers when using lead shielding.

Introduction and Purpose

• The use of standing CT (sCT) for equine imaging is increasing in clinical practice due to its diagnostic benefits.
• However, radiation exposure to personnel who remain in the CT room during scanning is a safety concern.
• This study sought to quantify radiation doses at typical personnel positions during simulated equine head and limb sCT scans to evaluate potential occupational risks.
• Positions mimicked in the study included the control operator, horse handler, and lead rope handler.

Methodology

• Radiation measurements were taken using an Equina helical fan beam sCT system (Asto CT Inc), specifically designed for standing horses.
• Scatter radiation was measured at various locations corresponding to where personnel would stand during imaging of the equine head and limbs.
• Entrance air kerma (a measure of radiation energy delivered per unit mass of air) was used to quantify dose using a spherical ionization chamber and electrometer.
• Personnel were assumed to be wearing protective lead aprons and lead eyeglasses during measurements to simulate actual safety protocols.

Results

• For simulated head scans with lead aprons:
  • Control operator location received 13.3 µGy (microroentgen equivalent doses)
  • Horse handler location received 3.5 µGy
  • Lead rope handler location received 6.8 µGy
• For simulated limb scans with lead aprons:
  • Control operator received 1.3 µGy during both pelvic and thoracic limb imaging
  • Lead rope handler received 0.2 µGy during pelvic limb imaging and 5.4 µGy during thoracic limb imaging
• The highest radiation doses were noted at the control operator position during head scans and at the lead rope handler position during thoracic limb scans.

Interpretations and Recommendations

• The measured radiation doses to personnel were low and below recommended occupational exposure limits when using lead shielding and eyeglasses.
• To further reduce exposure, the study recommends:
  • Limiting the number of personnel inside the sCT room during scans.
  • Rotating personnel between handler positions to distribute dose evenly.
  • Increasing the distance of operators from the scanner where possible.
  • Consistent use of lead shields and leaded eyeglasses for all personnel in the room.

Conclusion

• This study supports that the novel Equina standing CT system delivers radiation doses to personnel within safe occupational exposure limits when appropriate protective measures are taken.
• Thus, scanning a large number of horses annually using this system is unlikely to result in harmful radiation doses to veterinary staff.
• These findings are important for ensuring safety protocols in equine veterinary practices using this technology.