Abnormal Chest X-ray . . . Must Do a CT Scan?

Environmental just means that the cause isn't within the body. Pnemonia, specific viral or bacterial infections, allergies,spores,etc are all environmental causing conditions which would contribute to an abnormal chest xray..A CT scan is used to detect any abnormalities, and picks up on anything that isn't normal. Lung cancer can be detected by using a CT scan, or any other cysts, absesses, or lumps. If they don't think the cause is internal or cancer related, they will need to rule it out by doing a CT. It's a safety precaution more or less. If the cause is environmental, then antibiotics, or other medications will be given to treat it.

My mother had some spots that were determined to be from allergens where she lived most of her life.

This happened to my mom in March, and it did turn out to be cancer. She was going through tests to get ready for hip replacement surgery, and a spot was detected. The CT scan determined it was cancer, and she immediately began treatment. Since August she is cancer free, and they continually do tests. She had another one done where the CT scan showed spots on her lungs, but a biopsy revealed it was a yeast infection in her lung. So, it could be environmental, too.