Hi Rick,
There is an article by the Harvard Medical Group that talks about Blood in urine after radiation. You can read the entire article here. You can also read about other causes here.
I hope this helps somewhat. Remember, online sites are great resources for information so that you are able to ask the important questions that will help you manage your healthcare, however they can not take the place of your doctor's solid medical advice.
Take care and stay in touch!
Vicki M