Recently, the environment of medical treatment in our country has become more strict. The purpose of this study is to find changes in the implementation of diagnostic imaging from the point of view of cost analysis, through the use of diagnosis procedure combination (DPC) data. The patient data has been extracted from the DPC data. We compared patients (n=693) in terms of their daily income, cost, and image examination cost ratio for malignant tumors in lungs. The results of this study indicated the ratio of the image examination cost of 040040xx99100x was 25.2% in the old grading sheet. The ratio of the image examination cost increased 42.4% in the new grading sheet. The implementation of diagnostic imaging was able to be made visible simply by analyzing the cost. We found one of the methodologies that connected the improvement of that standard treatment with the examination of each DPC.