OPTIMIZATION OF PATIENT RADIAITION DOSE AND IMAGE QUALITY IN PLANAR DIAGNOSTIC RADIOLOGY

Abstract

Medical imaging using X-radiation is useful for supporting diagnosis of numerous diseases, but due to radiation risk, patient protection is an important safety issue. For that, the assessment of radiation dose to patients as well as the necessary image quality level that support diagnosing the suspected pathology is required for optimized X-radiation imaging. This prospective study aimed to investigate the factors affecting the patient’s radiation doses and the associated radiographic image quality in the real practice of common planar radiography examinations. Patient entrance surface air kerma (ESAK (mGy) during chest, abdominal and pelvis X-ray procedures in screen film radiography (SFR) and computed radiography (CR) along with the associated image criteria were assessed in ten selected x-ray departments in Khartoum state hospitals. The assessment was carried out using the internationally recommended standards and guidelines in order to recommend on national diagnostic reference levels (DRLs). Quality control (QC) tests, clinical referral issues and causes image rejection were conducted as initial part of this study. Patients' dose and image quality were evaluated for a total of 846 patients. ESAK (mGy) were calculated from exposure parameters using DosCal software. The X-ray tube output (mGy/mAs), accuracy of exposure factors, linearity and reproducibility were measured using an Unfors Xi dosimeter, while densitometry measures were performed using processor control densitometer, serial number 211-2176F. Image quality was evaluated by using the visual grading analysis technique and based on the European guidelines Quality Criteria for Diagnostic Radiographic Images. Based on the obtained results, the mean percentage and range of good quality images were 71.3 (56–86.1) for chest posteroanterior (PA), 76.1 (65–91) for abdomen anteroposterior (AP) and 70.7 (35.7–92.6) for pelvis (AP). These findings regarding image quality reveal wide variations among the various hospitals and procedures with moderate staff awareness about the guidelines. The corresponding mean ESAK (mGy) were 0.5 ± 0.3, 3.7 ± 1.7 and 3.6 ± 1.6 per procedure, respectively. The ESAK values for patients undergoing abdominal and pelvic X-ray procedures VII showed comparable values in relation to the international diagnostic reference levels (DRLs), while they were twice as high for chest X-ray procedures. There are main factors contributed in these findings. These include; Faulty X-ray machines, improper image processing conditions, exposure factor errors and patient communication errors. Applying of an organized and comprehensive quality control program within these departments specifically and within other similar departments in Sudan generally, as well as establishing quality criteria associated with DRLs for the various radiographic examinations based on the international recommendations is critical to maintain the desired image quality, while keeping the radiation dose to patients at a reasonable level. Finally, the transition from conventional screen film radiography (SFR) to digital technology in diagnostic radiology with the staff training are required as part of the optimization process.