xrays and flatulence

I had bypass surgery 5 years ago and have had a storybook recovery and weight loss since then.  The only problem i have had is that my wife has  said since the surgery i have an excess amount of gas (flatulence).  Well i haven't worried too much about it until just recently.  I have had several xrays because of kidney stones since surgery and they always say i have a lot of gas and it makes the kidneys and especially the stones difficult to see.  They have always managed to see the stones and do the lithotripsy procedure to break up the stone.  However a couple of days ago i was scheduled for lithotipsy and the gas in my large intestine prevented the doctor from seeing the stone so the procedure had to be cancelled.  Now i have a stint in so my kidney will drain and am waiting in hopes the gas will clear up.  With all that said has anyone else had this problem and is the fix as simple as gas x or is some sort of diet change in order.  If anyone has any suggestions i would certainly appreciate hearing them.
john