Optimization of exposure factors on radiographic examination chest AP supine with 15% kV rule method

The supine AP chest radiograph is an examination that is often performed in diagnosing and as an indicator of treatment, so this examination has become more frequent compared to other radiographic examinations during the COVID- 19 pandemic. The purpose of this study is to find out how to optimize the use of exposure factors radiography examination of the chest supine AP using the 15% kV rule method. Descriptive quantitative research method carried out in the laboratory of the Department of diagnostic imaging and radiotherapy, Health Polytechnic of the Ministry of Health, Jakarta 2 using computer radiography, X-rays, piranha radiation detectors, and anthropomorphic phantoms. Statistical analysis of the one- way ANOVA test to determine the effect of the 15% rule method on image quality Contras to noise ratio (CNR), and determine the appropriate optimization procedure using the figure of merit (FOM). The results of the one-way ANOVA test have a p-value of 0.995, so there is no significant difference in the CNR value to changes in the exposure factor using the 15% kV rule method. Then the FOM results show that the correct optimization procedure using an exposure factor of 85kV 2.5mAs can provide a dose of 0.22 mGy while maintaining optimal CNR image quality.