Study of Optimal Angle When Taking Foot AP Weight-Bearing Radiography

족부전후방향 체중부하 촬영 시 적정 입사각에 관한 연구

Incident X-ray angles of weight bearing foot AP radiography which differ in each medical institution were compared. Optimal angles were derived from the study and suggested as basic data for clinical application. 19 patients with no abnormality on right foot took part in the study from June 2013 to July 2013. Weight bearing foot AP radiography in the correct position was examined with the incident X-ray angles of $10^{\circ}$, $15^{\circ}$, $20^{\circ}$, $25^{\circ}$, $30^{\circ}$, and $35^{\circ}$. All the images were evaluated subjectively by 5 radiological technologists of over 15 year work experience using Likert scale as 1 for 'very poor', 2 for 'poor', 3 for 'fair', 4 for 'good', 5 for 'very good', 6 for 'excellent', and analyzed with ANOVA and Scheffe. Image quality was the most optimal at $20^{\circ}$ as 4.53, and relatively good at $25^{\circ}$ as 4.38 and at $30^{\circ}$ as 4.18. $35^{\circ}$ and $10^{\circ}$ were relatively poor. The average points of 6 groups indicated statistically significant difference (p<.01). In the post-mortem, 3 subgroups showed no statistically significant difference, and the average point of the groups of $20^{\circ}$, $25^{\circ}$, $30^{\circ}$was evaluated relatively higher than the other 2 groups. An optimal incident X-ray angle within the range from $20^{\circ}$ to $30^{\circ}$ for weight bearing foot AP radiography could make it possible to obtain the image of high diagnostic value and would be useful for clinical application in the future.