CAMRT Radiography Practice Exam

What is the angle of the CR for a Barium Enema sigmoid shot if the patient is prone?

1. 20-30 caudad

2. 30-40 caudad

3. 40-50 caudad

4. 50-60 caudad

The correct answer is: 30-40 caudad

When performing a Barium Enema for a sigmoid shot with the patient in a prone position, the central ray (CR) should be angled appropriately to best visualize the anatomy of interest and to prevent superimposition or distortion of the sigmoid colon. The recommended angle for this positioning is between 30 to 40 degrees caudad. This angling directs the x-ray beam toward the area of interest while compensating for the natural curvature of the spine and the position of the sigmoid colon. A caudad angle helps to align the radiographic beam perpendicularly to the long axis of the sigmoid colon, resulting in a clearer image while minimizing the risk of overlapping structures. Other angles, whether lower or higher than this range, might not adequately demonstrate the anatomy, potentially leading to unclear images or misinterpretation of the results. Thus, the 30-40 degrees caudad angle strikes a balance between optimal visualization of the sigmoid colon and proper technique when the patient is positioned prone.