Monte Carlo evaluation of occupational exposures in equine radiology procedures.

Portable X-ray equipments are commonly used in diagnostic radiology of equine patients. Despite its benefits, the exposure to ionizing radiation can pose a health risk to workers as physical restraint of patients is typically required. In this context, the aim of this study was to apply Monte Carlo simulation to investigate occupational exposure in the diagnosis of horses. The simulations were carried out by the Monte Carlo N-Particle 6.2 (MCNP6.2) code. The workers were represented by a FASH3 (female) and MASH3 (male) virtual anthropomorphic phantoms. To simulate the horse, a realistic virtual anthropomorphic phantom was created by voxelizing a commercially available 3D model. The spectra were calculated using the SpekCalc program with parameters: 90 and 100 kV, anode angle of 20°, filtration of 2.7 mmAl and field of view of 43×35cm. In the first simulated scenario, workers do not utilize personal protective equipment (PPE). In the second scenario, workers use PPE (lead apron, thyroid protector and lead glasses) and accessories to increase the distance from the patient/X-ray. The results are presented as conversion coefficients for Equivalent Dose (CC[H]) and Effective dose (CC[E]) normalized by the Air Kerma. Without protection, the most exposed organs/tissues of the assistants were: thyroid, for the woman, and breasts, for the man. In the most critical scenario, the assistant CC[E] values are higher than tube operators by a factor of 28. The combination of PPE use and increased distance reduced these CC[H] by at least 99% for the assistants and 97% for tube operators.