Why do I need to have a full bladder when I have radiation treatments?
Why do I need to have a comfortably full bladder when I receive a radiation treatment?
Actually filling your bladder full of air would be a VERY bad idea. You don’t want to create a tissue/air interface like that in an area that’s being treated by radiation. You wouldn’t get good coverage which is what you want.
To answer your question. I’m assuming this is for prostate cancer. The prostate (or if it’s not that, other parts in that area) will move around some during treatment. For prostate cancer, the radiation is very localized on the cacerous tissue. You want it to be in the same place every day. Because there isn’t much of an indicator besides your initial CT, and you don’t get a CT every day (it doesn’t show up in the films they take) they have to try to have the conditions as close to the original conditions as possible.
Another consideration is surface area. If your bladder is full, less of the surface area of the bladder will be hit by the radiation during treatment – which will mean less complications for you down the road. Less of the bladder will be getting the full dose. I hope that helps, if you need further clarification you can email me or ask your doctor. I’m sure he/she would be happy to answer 
Or you can ask a therapist.
Also – your urologist will not be able to answer these questions. This is a question for your radiation oncologist.
do they use ultrasound before the radiation? I know they want a full bladder then to see images better.
References :
Are you receiving Radiation To Your Bladder? Ask your doctor for clarifcation on why they want you to have a "comfortably full bladder" for it.
References :
Probably so that the liquid holds it out in shape so you get even exposure. Your other option is to have a catheter inserted that fills your bladder with gas (usually nitrogen) to hold it all out evenly. Not very comfortable at all….
But you should really be asking these sorts of questions of your urologist, not of a bunch of strangers on the Interwebs!
References :
Actually filling your bladder full of air would be a VERY bad idea. You don’t want to create a tissue/air interface like that in an area that’s being treated by radiation. You wouldn’t get good coverage which is what you want.
To answer your question. I’m assuming this is for prostate cancer. The prostate (or if it’s not that, other parts in that area) will move around some during treatment. For prostate cancer, the radiation is very localized on the cacerous tissue. You want it to be in the same place every day. Because there isn’t much of an indicator besides your initial CT, and you don’t get a CT every day (it doesn’t show up in the films they take) they have to try to have the conditions as close to the original conditions as possible.
Another consideration is surface area. If your bladder is full, less of the surface area of the bladder will be hit by the radiation during treatment – which will mean less complications for you down the road. Less of the bladder will be getting the full dose. I hope that helps, if you need further clarification you can email me or ask your doctor. I’m sure he/she would be happy to answer
Or you can ask a therapist.
Also – your urologist will not be able to answer these questions. This is a question for your radiation oncologist.
References :
I work in radiation oncology.