Influence of tube voltage on digitized image qualityof patients exposed to occupational dust: phantoms and clinical studies

摘要

Background High-voltage analog X-ray examination is a main tool for pneumoconiosis,which is challenged by digital radiography (DR).The tube voltage of DR chest films required for diagnosis and staging of pneumoconiosis is concerned technically.We investigated the influence of the tube voltage on chest X-ray DR image quality of patients exposed to occupational dust.Methods DR images of the CDRAD2.0model,an anatomical chest phantom,and 136 exposed workers were analyzed at different tube voltages by threereaders.Image quality factors (IQF) were calculated and compared using the CDRAD2.0 model.DR images of ten anatomic positions were scored against those of the high-kilovolt chest films in anatomical phantom and clinical cases,and differences in scores were analyzed.Results In the CDRAD2.0 model,all three readers had a minimal IQF at 120 kV (mean:22.25 kV).The differences in the mean IQF of DR images at different tube voltages was significant (F=13.78,P＜0.001).The IQF of DR imaging at 120 kV was similar to high kilovolt analog imaging (t=-0.58,P＞0.05).In the anatomic phantom and clinical cases,the DR images at 120 kV were closest in anatomical detail to the high W analog images,and the means were similar (P＞0.05).Conclusions Among different tube voltages,DR image quality is closest to the high kilovolt analog images at 120 kV in patients exposed to occupational dust.