My husband went for xray on his lungs the xray machine was shaking could it give a false reading .

X ray: Probably doesn't matter. X ray machine is the source for x rays which travel like beams of light. If the cassette or the patient is moving, the images will come out blurry. The tech usually checks the images, if they aren't good he will take them again.

Not likely: Shaking of any form while obtaining a chest x-ray is most likely to produce motion artifact which has the effect of subtle blurring of the image, much like a camera. If this were to slip by the technologist without being noticed (rare), the radiologist would recommend a repeat study (sometimes needed) because the motion makes it less sensitive for showing subtle findings (but not a false reading).