Check the images (One of the images aren't so clear, so I marked the gases)

The urologist ordered K.U.B to get more info. about renal stone and the examination was done twice, and in both, there were gases that masked some info. my Q is, how can we improve the results next time, will taking castor oil instead of bisacodyl and glycerin improve the results or there is a problem with the preparation that she should avoid? Because first time, she took glycerin instead of castor oil, and bisacodyl in the next time she underwent the examination because of fearing strong adverse reactions associated with castor oil (Cytotoxicity and neurotoxicity as shown by animal studies)

She followed all the procedures except the castor oil step (Replacing it with other laxatives)

This is the preparation ordered by a radiology center :

1- Light dinner (Example: Jam, plain biscuit, boiled vegetables, fruits, honey) 10:30 PM that doesn't contain dairy products, fats, soft drinks and legumes

2- Ingesting 60 ml castor oil

3- Drinking anise tea without sugar 12:30 am

4- Drinking anise tea without sugar 1 am

5- Take disflayl (simethicone) 2 chewable tablets (without water) every half an hour 3 hours before the examination