I'm finding it more and more common for facilities all across the country to require that all PA chests be attempted lengthwise first, regardless of whether or not you believe the lungs will fit on a lengthwise film. If you are reading this and your facility does this, I would be interested in learning about the reason for it.
I have heard that some Radiologists prefer this because they can get a better assessment of heart size when comparing with a lengthwise film on the next monitor over. When performed crosswise, the monitor (due to its shape) decreases the image size in order to fit the whole radiograph on the Doctor's screen, making the comparison lengthwise chest x-ray a different magnification. My issue with this is that handy dandy measure tool on the PACS system. If we have the capability to plot measuring points and obtain a detailed measurement, we should still be able to acquire an accurate assessment of how large the heart is with a few extra seconds of mouse-play. If this is the only reason for the lengthwise chest to be performed first, it would seem that radiation protection standards are being compromised in order to save a few extra seconds for the Doc.
So far, this is the only reason I have heard of for performing the lengthwise chest prior to obtaining a crosswise to include the costophrenic angles. If there are more reasons out there, I would love to hear them from you.
Here comes the disclaimer:
I would absolutely NOT recommend (especially for students reading) that you approach your Radiologists with this in an accusatory manner. To simply ask a question is what I am hoping to accomplish here. Managers, Radiation Safety Officers, and the Radiologists should be making these decisions, and tact will go a long way to preserving your Technologist - Radiologist working relationships. I would hope that you could gather information out there, and have discussion in here with the convenience of anonymous comments :-)