Optimisation of patient protection and image quality in diagnostic radiology

Abstract

Objective: To determine the examination frequencies, quality of radiographic images and the entrance surface dose (ESD) in patients undergoing general radiographic examinations. Design: Prospective study on the device performance, film reject rate, patient dose, and image quality during the use of standard and fast speed film screen combination. Setting: Radiology Department of Kenyatta National Hospital, a referral, teaching and research hospital in Kenya. Subjects: A total of 837 adult and 229 paediatric patients undergoing diagnostic examinations were assessed for patient dose and image quality. Interventions: The X-ray tube output measurements and X-ray exposure parameters were determined. The patients ESD on standard 200 and fast 400 speed film screen combination was determined. The radiographic image quality was assessed. Main outcome measures: The findings were compared with the international diagnostic reference levels (DRL’s) for determination of dose optimisation in diagnostic radiography. Results: The relative frequency of examination was 80% and 20% for adults and paediatric patients respectively. The image quality improvement by 13% was achieved and patient dose reduction range of 31% to 77%. Conclusions: The patient dose reduction and image quality was achieved through a quantitative quality control (QC) assessment of processes involved in producing radiographs. The study leads to the introduction of the concept of plan- do-check-act on QC results and optimise with a view of patient dose reduction. The department appreciated the value of a quality assurance (QA) programme and continues to collect data for establishment of DRL’s.