Patient Dose Estimation from Digital Radiography Repeat Rate

Abstract

Purpose: This research aimed at estimating the patient effective dose from digital radiography repeat rateand evaluating the factors that contribute to the repetition of radiographic procedures in two referral hospitals in Sari, Iran.

Materials and Methods: Entrance skin dose and effective dose per common radiography procedures in digital radiography were measured. 1724 X-ray exposures were investigated prospectively. The annual number of each radiography procedure was obtained from the archives of the digital radiography department. The patient cumulative dose was the calculation from annual exposures Repeat Rate (RR) and effective dose per digital radiography procedures.

Results: The mean exposure RR per examination was 1.12% and the total percentage of a repeat of all examination was 8.9%. Annual cumulative dose (man-mSivert) resulted from radiographic RR was 449.2.The chest and lumbar spine radiography had the highest annual number and the highest radiation dose, respectively; therefore, these procedures transfer the largest annual dose from repeated radiographic images to the patients. The factors leading to the repetition included the radiographer error (69%), the X-ray tube and equipment error (10.4%), the patient related error (16.1%) and other cases (4.1%). The average effective dose for each examination was 0.36 mSv.

Conclusion: Digital radiographic repeat rate increases a 1.1 % annual patient effective dose from the base level that receives from the current radiographic examination. Inconsistency of the center of the digital panel and the central axis of the X-ray beam and error in the selection of the upright or table digital panel are among the most important factors in the repetition of digital radiography.