I can only speak surrounding RT etc only guessing similar circumstances re wind etc. Were advised that if necessary a diet change may be suggested if wind etc were to be a problem as certain fruit, veg, fibre rich foods do cause excess wind e g broccoli. So,sometimes,a good diet may be a hindrance but, this is said under the guidance for RT sessions, sometimes change of diet is not advisable. I would guess the CT scan people have come across this many times and reckon the laxative is the way to go.
W