Comparison of Foot Bone (Ossa Pedis) Angulation in Anteroposterior (AP) Projection with Central Ray at 0°, 10°, and 15° in the Radiology Department of Gunung Jati Hospital

Abstract

Accurate radiographic visualization of the foot (ossa pedis) is essential for reliable diagnosis, given the complex anatomy and overlapping structures of the tarsal region. However, there remains no clear consensus regarding the optimal central ray (CR) angulation for anteroposterior (AP) foot radiography in clinical practice. This study aimed to compare the diagnostic image quality of AP ossa pedis radiographs obtained using CR angulations of 0°, 10°, and 15° at the Radiology Department of Gunung Jati Regional Hospital, Cirebon City. A comparative evaluative design was employed using a standardized digital radiography protocol. All images were acquired with a fixed source-to-image distance of 100 cm and identical exposure parameters (45 kV, 10 mAs) to isolate the effect of CR angulation. Image quality was assessed using blinded Visual Grading Analysis by five expert evaluators based on the visibility of key tarsal and tarsometatarsal joint structures. Quantitative analysis was performed using mean score statistics. The results demonstrated that both 0° and 10° CR angulations yielded superior and equivalent image quality (mean score = 3.2), classified as good, with clearer joint space visualization and minimal anatomical distortion. In contrast, the 15° CR angulation produced a lower mean score (2.8), indicating adequate image quality with increased structural overlap. These findings suggest that 0° and 10° CR angulations are more suitable for routine AP ossa pedis examinations, providing evidence-based support for protocol optimization in clinical radiography practice.