Re: still reading the postings, still learning from them
Image-Guided Radiation Therapy (IGRT) is important in avoiding side-effects of treatment and is especially important to you because of your previous TURP. There are two ways to do it. They can implant in your prostate little gold markers about the size of rice grains called fiducials. Or, they can implant small radio transponders (This is called Calypso). Either one works fine and enables them to track the position of your prostate between treatments - called inter-fractional motion. IGRT is often combined with IMRT in such systems as Tomotherapy and many others.
CyberKnife additionally tracks the motion of the prostate during each treatment - called intra-fractional motion. With CyberKnife, IGRT is combined with SBRT.
With proton therapy, they place a balloon in the rectum during each treatment. This holds the prostate in place so it doesn't move around too much.
The better they track the motion of your prostate, the more the radiation treats only the prostate and not the places you don't want the radiation to go, like the rectum, the bladder neck, the penile bulb and the pelvic bones. Even with the sub-millimeter accuracy of CyberKnife there will be some acute and possibly some late-term urinary and bowel irritative symptoms. Also, some men are more sensitive to the irritative side effects of radiation than others.