Signal Detection Theory (SDT) is a valuable framework for studying decision-making processes. In this research, SDT was applied to evaluate the decision skills of medical students in diagnosing trauma radiography. To assess their performance, pre-test and post-test evaluations were conducted, providing each student with 50 trauma radiographic images (25 depicting injuries and 25 without injuries). The students were required to indicate whether they observed an injury or not. Based on their responses, the students' behaviors were categorized as liberal, conservative, or optimal, with the latter representing the desired behavior. The actual response bias and sensitivity were calculated for each student and compared the results between the pre-test and post-test stages. As a result, no optimal behaviors were observed during the pre-test; however, in the post-test, four students demonstrated optimal behaviors. An increase in conservative behavior among students during the post-test was observed, indicating an enhanced sense of awareness and caution. This change can be attributed to the focus and encouragement provided to the students throughout the study. Although no significant differences were found in the actual response bias values between the pre-test and post-test, noteworthy behavioral changes were observed. By employing SDT, this research highlights the decision-making abilities of medical students in trauma radiography diagnosis. The findings indicate that targeted interventions and training programs can play a vital role in improving decision-making skills. Further investigations are warranted to explore effective strategies for fostering optimal decision-making behaviors among medical students in radiographic diagnosis.