Capability Analysis of Diagnostic Radiological Machine for Clinical Chest Examination Outputs

Abstract

Heart failure is being characterised by many factors ranging from high blood pressure, stress, medication, obesity and other medical complications. Radiological examination offers potential diagnosis of congestive heart failure. This work investigated Capability Process Analysis of Cardiac Thoracic Ratio (CTR) based on radiological chest X-ray examination using MX.4 Radiological Diagnostic Machine (DRM). The raw data were sourced based on the output of the MX.4 DRM for 150 samples of X-ray films divided into 25 samples of 5 subgroups and evaluated cumulatively. Simulated CTR values were generated using uniform distribution process. Specification limits were set on 3sigma ( ^  3  x ) for both upper and lower limits-(USL and LSL) and tolerance limit was established by T  0.05 with target value of T  0.5 based on the specification criteria for non-sensitivity analysis of CTR result. Statistical process control and capability analysis were adopted to address process stability and indices for the two processes. Normal probability plots and empirical CDF functions investigated the mean pattern of the raw and simulated values. Bartlet ‘b’ statistic ascertained the degree of homogeneity in the process. Data analyses were performed using statistical software MINITAB version 16.0 and Excel package. Findings revealed that raw computed CTR values and simulated CTR values were operating under 1.0 – 1.3 sigma level. On the average 33% of the raw CTR values obtained fall outside the specification limits while the pk p C  C indices for all the cumulative raw CTR values suggested that the process is off centered and shifted from the target value indicating that the variability in the raw CTR process is very high compare to the simulated CTR values. The study concluded that there was significant shift in the CTR values towards upper specification band. The variability in the CTR value of patients can be minimised through the right education about the health risk associated with CTR>0.55. The study recommended shift in the target value of CTR to 0.52 to maintain accuracy based on possible inherent factors. Health awareness campaign on slow death resulting from heart failure in absence of early detection of abnormality in CTR among patients should be created by the government and health agencies. Patients should be medically advised on the measures to control and maintain stable CTR. Further study should be conducted on large repeated experimental CTR samples to ascertain the reliability of this study. Finally, follow up study of patients should be undertaken by the cardiologist to reduce the possible health risk that associated with CTR.