I have three x-ray images (exported as JPEG) taken from the same patient. those three images are taken at different positions:1. patient standing erect 2. patient performing left lateral bending 3. patient performing right lateral bending.
I am trying to measure the length of the spine using ImageJ, and I am converting the measurement from pixels to millimeters using the annotated ruler (real-life scale).
ideally, I am supposed to get very similar spine length, however, I am getting about 60-millimeter difference between the erect and the lateral bending and a difference of about 17 mm between the right and the left lateral bending.
please guide me what might be the reason for the discrepancy? what should be fixed?