Which of the following is NOT a method used in an X-ray exam?

The correct choice is based on understanding the different imaging methods used in medical diagnostics.

A pyelogram is a type of X-ray exam that specifically focuses on the kidneys and urinary tract, often using a contrast dye to visualize the structures involved. A bronchogram involves taking X-ray images of the bronchial tubes after a contrast material has been introduced, which helps assess lung conditions. A GI series, or gastrointestinal series, is also an X-ray examination that examines the digestive tract using a contrast agent.

On the other hand, a cardiogram, which is related to cardiology, typically refers to an electrocardiogram (ECG or EKG), a test that records the electrical activity of the heart and is not an imaging technique using X-rays. This distinction highlights that while the other options involve X-ray examinations, the cardiogram does not, making it the correct choice for the method that is not used in an X-ray exam.