Equine Standing Multidetector Computed Tomography of the Distal Thoracic Limb and Tarsus Has a Lower Cumulative Radiation Dose than Digital Radiography

Recent technological advancements in CT have improved the ability to scan standing sedated horses. However, the impact of radiation exposure on veterinary staff while scanning the extremities of standing horses using this technique, compared with digital radiography (DR), remains unknown. This study compares the radiation exposure of imaging technicians assisting with multidetector CT (MDCT) and DR of the distal thoracic limb and tarsus in standing horses. Personal dose equivalent was measured on four body locations: thyroid gland, gonads, hand, and feet. Images of the distal thoracic limb (n = 12) and tarsus (n = 12) were obtained from 24 Warmblood horses using DR and MDCT. The DR included four views of the front fetlock (dorsopalmar, lateromedial, dorso45lateral-palmaromedial oblique, and dorso45medial-palmarolateral oblique), three views of the front foot (dorsopalmar, lateromedial and dorso65proximal-palmarodistal oblique) and four views of the tarsus (dorsoplantar, lateromedial, dorso45lateral-plantaromedial oblique and dorso45medial-planterolateral oblique). The MDCT scans included the distal metacarpus to the foot and the tarsus. Noninferiority testing showed lower radiation exposure to the imaging technician during MDCT of the distal thoracic limb and tarsus compared with DR, measured at the thyroid gland, hand, and feet. The radiation exposure to the gonads during MDCT of the thoracic limb was significantly higher than with DR. Nevertheless, the lower cumulative radiation exposure for the assisting imaging technician during MDCT compared with DR suggests that the tested MDCT setup enables advanced imaging of the distal limb in standing sedated horses, offering both reduced radiation exposure and avoiding the patient-related risks of general anesthesia.