pg72,
You are being treated with a protocol that is only being used at MSKCC under
a clinical trial. Because there will be only 44 men treated with that protocol, you aren't likely to hear from them on this site.
The PSA drop from 5.5 to 0.73 is certainly encouraging. In fact, it's so good that it raises the question as to whether any more radiation is really needed. They use a strong radioisotope (Pd 103) that delivers its radiation more quickly, which is why you are experiencing more acute toxicity this early. I have no doubt that this will be a curative therapy for you; the question the trial is trying to answer is what is the toxicity associated with this unique protocol.
I hope you will keep posting about
your progress.