Assessment of kVp Accuracy, Reproducibility and Consistency in diagnostic x-ray units of some selected hospitals and radiology centres in Jos and environs, Plateau state Nigeria.

Abstract

To ensure that radiation doses received by both patients and medical staff are kept as low as reasonably achievable. Quality Assurance program implementation in conventional diagnostic radiology is necessary. The exposure factors of the x-ray machine need to be checked from time to time as required by the International Commission on Radiological Protection
 (ICRP). In this research, assessment of the tube output variation with kVp accuracy, reproducibility and consistency in diagnostic x-ray units of some selected hospitals and radiology centres in Jos, Plateau state were carried out using Gammex digital kV meter with model number: 330. Eight hospitals x-ray units and four radiology centres were studied and the test for kVp accuracy, kVp consistency and kVp reproducibility were conducted on the x-ray machines at varied kV and mAs set on the control panel at a focus to film distance of 10m. From the results obtained, seven x-ray units (58%) had values ranging from (1.78 to 4.26) within the tolerance limit of ±5% in kVp accuracy while five x-ray units (42%) were above the tolerance limit. In kVp reproducibility eight x-ray units had values ranging from (1.52 to 9.78) within the recommended tolerance limit of ±10%, while four x-ray units were above the recommended tolerance limit with values between (- 13.30% to 15.86%) and in kVp consistency with the recommended tolerance limit ±5%, 67% of the x-ray units were all within the tolerance limit with values ranging from (-0.8 to -5.0) but 33% had values (5.3 to 18.1) of high deviations outside the tolerance limit. This show that the set value of exposure factor kV from the control console gives values within the tolerance limit for about 67% of the studied x-ray machine, meaning there is a good quality assurance programme in place most of the diagnostic x-ray units studied.