Comprehensive investigation of radiation protection in veterinary hospitals in Changzhou, China.

Abstract

To assess the current status of radiation protection in Changzhou veterinary hospitals. Questionnaires were used to survey the veterinary hospitals and their radiation workers, questions included veterinary hospitals' basic information, location, type of X-ray diagnostic equipment, and personal information, status survey, the radiation cognition of the radiation workers. In search of veritable data for the estimation of occupational doses, an AT1123 radiation survey dosemeter was used to simulate the measurement of the ambient dose equivalents around the head and neck of a radiation worker operating in the imaging room. RaySafe RF was used to measure the air kerma at the center of the irradiation field and 0.5 cm from it. RaySafe RF and related phantoms were used for performance tests of X-ray diagnostic equipment. A total of 118 veterinary hospitals, 118 radiation workers, and 119 X-ray diagnostic equipment were surveyed. Among the 119 X-ray diagnostic equipment, 118 were DR (Digital Radiography) for veterinary practice, and 1 was a general-purpose CT scanner. The 118DRs cover 31 brands (manufacturers), the top six brands of DRs accounted for 68% of the total. A portion of the veterinary hospitals did not fully consider radiological protection in site selection (most veterinary hospitals were located near shops or residential areas), imaging room location (only 53 X-ray diagnostic devices are set on the first floor), and imaging room shielding. One hundred and seventeen (98.3%) X-ray diagnostic equipment needs to be operated while the radiation workers stay in the imaging room. Individual monitoring of occupational external exposure was carried out in 117 (99.2%) veterinary hospitals, and 59 (50.0%) did not carry out health surveillance for radiation workers. Twenty three (19.5%) veterinary hospitals placed Thermoluminescent Dosimeter (TLDs) in the imaging room or even next to the X-ray tube. The vast majority of radiation workers manually restrained pets (93.2%) and the majority (84.7%) of radiation workers refused to wear lead gloves during restraints, resulting in occasional exposure of their hands to the primary beam. The performance tests of X-ray diagnostic equipment of six DRs found that DRs of four (66.6%) brands had unqualified indexes, and the main unqualified indexes were the linearity of tube output of two DRs (33.3%) and alignment of X-ray field of three DRs (50.0%). The air kerma in the irradiation field of DRs ranged from 122.3 to 410.4 uGy, and there were obvious differences between the air kerma in the irradiation field and out of it (Z = -5.125， P <.001). The ambient dose equivalents around the head and neck of animal restrainers ranged from 22 to 182 nSv. The site selection of the veterinary hospitals, and the placement of the imaging room are not optimized because of the lack of occupational hazard assessment, the routine performance tests of X-ray diagnostic equipment are not carried out, and the occupational health examination and personal dose monitoring of radiation workers are not up to the standard. Animal restraint by workers are relatively common and dosemeters are occasionally inappropriately placed. Relevant competent departments should introduce radiological protection standards for veterinary hospitals promptly.