If dispo is king in the ED, the plan is the prince. But imaging plans can be tricky. You want to look at someone's abdomen, sure. But CT or MRI? Or is this one of the rare instances plain films help? Do they need IV contrast? PO contrast? By no means exhaustive, the guide below outlines common points of confusion with radiology. X-ray -AP vs PA Lateral: The "AP" or "PA" refers to the direction the beam is traveling to the receiver - either anterior to posterior (AP) or posterior to anterior (PA). Despite this being an x-ray this matters because is changes the observed size of images. Imagine your lamp is the x-ray beam and your desk is the receiver: putting your hand close to the desk results in a small hand shadow, moving it towards the lamp increases the size of the shadow. Why we care about this happening at all is the cardiac shadow on a chest x-ray. When the beam goes AP the heart, being more anterior, casts a bigger shadow that may overemphasize