AP C-Spine

AP C-spine. This AP C-spine was done with the phantom supine on the table, using the table bucky with a 37-inch SID at a 15-degree cephalad angle on the x-ray tube beam. For every 5 degrees that the x-ray beam is angled, a 1-inch deduction is to be done of the SID. 

According to the proportional anatomy chart, an AP C-spine is equivalent to an AP femur. For the first exposure, the same technique was used from the AP femur. That kVp of 74 with a mAs of 6.3 resulted in a DI value of 1.3, outside of the optimal range. 

When looking at the image, the group realized that the collimation was too tight, and it completely cut off T1. The group decided for the next exposure to open the collimation but keep the technique the same. This resulted in an image with a new DI value of 0.4.