Penerapan Modifikasi Faktor Eksposi Aturan 10 kV Terhadap Kualitas Citra Radiografi Thorax Modalitas CR vs DR

Abstract

Background: The use of Computed Radiography (CR) and Digital Radiography (DR) makes Radiographers pay less attention to the selection of exposure factors, resulting in overexposed and underexposed. One technique for optimizing and maintaining image quality in CR and DR is modification of the exposure factor of the 10kV rule. This study aims to compare image quality (histogram, noise, signal to noise ratio (SNR), and exposure index (EI)) in CR and DR by applying the modified exposure factor rule of 10 kV to chest radiographs.

Methods: Quantitative research with an experimental approach using the Perlove PLX 101 C mobile X-ray aircraft, thorax phantom, CR Prima T2 and AeroDR 3 1417HL DR detector. Data was generated by exposing the phantom using an anteroposterior (AP) chest radiography examination technique. Exposure was carried out 3 times for CR and DR with 60kVp 10mAs, 50 kVp 20 mAs and 70kVp 5mAs. Noise measurement through region of interest (ROI) in the background area. The SNR value with ROI is a comparison between the mean value of the pulmonary and costal anatomy with background noise. CR and DR image histograms were obtained using the Image-J application. Exposure index and sensitivity values by looking at the CR monitor. Then the data is processed and analyzed statistically.

Results: Modification of the 10 kV regulatory exposure factor produces the highest noise image at 70kVp 5mAs, namely 7.82 in CR and 10.6 and there are differences between other exposure factors with a p-value <0.001. The pulmonary and costal SNR values in DR were higher than the SNR in CR for all exposure factors and there was a difference with a p-value <0.001. The histograms on CR and DR are flat and homogeneous. The highest CR exposure index value was at 60kVp 10mAs, namely 2760 and the lowest was at 70kVp 5mAs, namely 1997 with sensitivity classified as overexposure for all exposure factors because it was below 75/mR.

Conclusions: Application of the modified exposure factor rule of 10kV to AP chest radiographs causes differences in the quality of DR and CR images. The lowest noise and highest SNR are found in DR images with an exposure factor of 50kVp 20mAs, but the lowest exposure index is at 70kVp 5mAs