During a recent health MOT, my GP suggested a chest X-ray after noticing ‘crackles’ when I breathed in and out. I am 62, a non-smoker and very active. What could be the cause? Dr Martin Scurr answers During a recent health MOT, my GP suggested a chest X-ray after noticing ‘crackles’ when I breathed in and out. I am 62, a non-smoker and very active. What could be the cause? Dr Martin Scurr answers