Whether or not you need to fast for a radiograph depends on the specific item for which the film is being taken. Because the filming here is more generalized, if the film is a chest film or abdominal flat film does not need to fasting, because whether or not fasting does not affect the flat film shooting. If the film is an upper gastrointestinal imaging, then you need to do the examination on an empty stomach, because the examination on an empty stomach can better observe the condition of the mucosa of the upper gastrointestinal tract. The upper gastrointestinal tract cannot be visualized properly without fasting, so the need for fasting depends on the specific test.