Investigation on entrance surface doses to patients from medical X-ray diagnosis in Inner Mongolia autonomous region

Objective To analyze the levels of entrance surface dose (ESD) to patients from diagnostic medical X-ray examinations in Inner Mongolia autonomous region. Methods The investigation of diagnostic medical X-ray examinations was completed in 30% of the number of hospitals under the requirement of the program plan of the national survey on frequency and dose from medical exposure. The investigation of ESDs to patients from general diagnostic X-ray examinations was carried out in terms of the scale of annual outpatients in different levels of hospital. The difference in ESDs to patients was compared for different equipments, different grade hospitals and different exposure sites, with the comparison result being subjected to rank sum test. Results In all types of diagnostic medical X-ray equipment, DR photography equipment accounted for the majority. During various routine diagnostic X-ray examinations, the average ESDs was lumbar vertebral 3.39 mGy, pelvic and hip 1.65 mGy, cervical spine 0.90 mGy, extremities 0.38 mGy and thorax 0.37 mGy, respectively. In the diagnostic examinations of chest, lumbar and cervical spine, the ESDs caused by the use of screen film photography equipment were higher than those by DR photography equipment, with statistically significant difference (Z=-3.229, -4.820, -5.265, P<0.05). Conclusions Screen film photography equipment results in higher ESD than DR photography equipment. The doctor′s operation behavior is an important factor that affects the ESD. Key words: Inner Mongolia region; Medical exposure; Diagnositc exposure; Entrance surface dose