Evaluation of Quality Control Protocols for Computed Tomography Scanners in Khartoum Centers

Abstract

Quality control (QC) in any activity refers to the routine and special procedures developed to ensure that the final product is of consistently high quality. Quality control in diagnostic radiology requires a planed, continuous program of evaluation and surveillance of radiologic equipment and procedures. The main purpose of this study is to assess the performance of some of CT scanners used for radiodiagnosis and to evaluate the quality control program in Khartoum State Computed Tomography (CT) centers. The main parameters monitored and tested during the QC program include, average CT number of water, field uniformity, noise, lower contrast resolution, high contrast resolution, slice thickness, bed indexing, couch travel accuracy, light field accuracy, contrast scale and linearity. The total tested CT machines were 7 out of 10. All of the tested scanners passed the following tests field uniformity, noise characteristics, bed index, high contrast resolution, light field accuracy, slice thickness, couch travel accuracy, contrast scale and linearity. However - for some of these scanners - deviations of the results from the standard values have reached the maximum tolerance and this indicates that those machines are in bad need for preventive maintenance. The percentage of success for other tests were 57.1%, and 50% for the average CT number of water, and low contrast resolution test respectively. The study showed also that there is no QA program performed regularly in most of the CT centers involved in this study, such program includes - among others - QC tests, calibration, staff training, preventive maintenance and repair. In addition most of centre do not have the QC tools and depend on the service engineer in calibrating and testing of their machines. Finally the study showed that there is more efforts are needed to enforce the SAEC act that regulates the use of radiation in different applications including the medical field.