PREDICTORS OF POSITIONING ERROR IN DIGITAL RADIOGRAPHY

Abstract

OBJECTIVE: To determine the factors responsible for the occurrence of film retakes by positioning error in digital X-ray radiography. STUDY DESIGN: cross-sectional. PLACE AND DURATION OF STUDY: Department of radiology aga Khan University and Patel hospital Karachi from January to August 2009. METHODS: X-rays of different body parts conducted during the study period at Aga khan hospital (n=45886) and in Patel hospital (n=7510) with digital radiography were included in this study (n=53396). Measurements were done for number of X-rays retake due to different quality control reasons in digital radiography. Quality control reasons included positioning errors and others (underexposure, over exposure, patient movements, grid cut off and equipment related) due to which X-ray quality was questionable. Radiographer (age, gender and radiographic experience) and patient related factors (age, gender, condition of patient and area of X-ray examined) that might cause X-ray retake in digital radiography were also evaluated. Multivariate logistic regression was applied to identify the significant predictors of positioning retake in digital radiography. RESULTS: A total of 670 (1%) digital X-ray radiographic examinations were observed where film retakes were performed due to positioning and other errors. More than half (57%) of the all films retakes were due to Positioning error alone. Multivariate analysis had shown that radiographic examinations by male radiographer decrease 35% risk of occurrence of positioning occur in digital radiography (C.I=0.47-0.9). Increase in the patient age and male sex of the patient were at significantly higher risk of causing positioning error as compared to other errors for film retakes (p-value <0.0001). Similarly other parts of body examinations were 2.3 times higher risk of producing positioning error as compared to abdominal examinations by digital radiography (C.I=1.7-3.3). CONCLUSION: Patient age, examination of parts of body other than abdomen, male patients and the digital X-ray radiographic examination performed by a female radiographer are the significant factors responsible for film retake due to positioning error. Key words : Digital; Positioning error; Retake; Radiography.