Your PSA should be <0.01 (ultrasensitive) six weeks after RP. 0.5 would indicate that there is residual PC somewhere. I concur with another person here in suggesting that you request another test to confirm that it isn't a lab error. I'd suggest that you request an ultrasensitive PSA test. As to your question regarding RT, the question really should be where the cancer is located. If it's in the "local" area then you could undergo RT (I'd suggest Tomotherapy which is the most advanced system in the market). If it's distant then RT won't result in "cure". Ideally you'll want to eliminate the possibility that it is either: a) in your bones or b) in your lymph nodes before determining to pursue RT. There are some sensitive tests available for both invovlement of bones as well as the lymph system. Regarding lymph involvement I'd suggest Combidex. Unfortunately that test has not been approved by our FDA so you'd have to go to the Netherlands for it. Once again, the primary question you should be asking is whether there are residual cells (anything above <0.01 would confirm this) and if there are residual cells locating where they are. If you find that the next PSA is above 0.01 then my best advice would be to seek a true expert in prostate cancer. There are a handful of those around the US. Best wishes to you.