Comparison Between Film-Screen and Digital Mammography for Woman Breast Cancer Screening: Mean Glandular Dose

Introduction: Most studies in mammography have only been carried out in a comparison of image quality and lesion detection in film-screen mammography (FSM) and full field digital mammography (FFDM) systems. The aim of this paper was to evaluate mean glandular dose (MGD) of patient and affecting factors by FSM and FFDM to estimate which one gives a brief radiation protection to patient. Material and Methods: The FSM units with fast and slow screen film detectors used for comparison to FFDM in this study. In addition to technical factors, a set of data consisting of age, weight, height and compressed breast thickness (CBT) were also recorded for each patient.Results: Entrance skin exposure (ESE) for CBT of 4cm, 27 kVp in FSM by fast and slow screen film detector, was 4.5 mR/mAs and 11 mR/mAs, respectively. But ESE variation by FFDM (Gitto) by Mo filter was 14 mR/mAs. In conventional units, mean CBT of 6.02 cm with fast and slow screen film detector were 1.55 and 1.96 mGy. In digital unit by mean CBT of 5.41 cm, MGD was 2.26 mGy, respectively. Significant correlations were observed between MGD and breast thickness, breast density, applied kVp and mAs.inConclusion: In spite of advantages presented by digital technology, this technology leads to a significantly greater MGD to patient when comparing to conventional mammography especially with fast film-screen mammography and patients with high breast thickness.