Charged particle therapy works MUCH better then IMRT because it attacks the double strand DNA directly. Using the bragg effect the energy is released mm's into the tumor and then STOPS! This is called a high LET while IMRT has a low LET. IMRT only works indirectly by causing free radical damage and repairable single strand DNA breaks. IMRT doesn't work well with tumors because of the tumor's low oxygen levels (hypoxia). Drugs are given to increase the oxygen level but this only enriches the Doctors who make a profit from their sale.

IMRT has little control because it is low mass electrons and when fired it will continue all the way through the body. It is a cheap to own and operate machine. There are at least 330 IMRT centers in the US. There are now 8 PRT centers with the last one in Virgina funded in part by the DOD. If you go to wikipedia and type in proton therapy, particle therapy, boron therapy or carbon therapy you can read more about this. The DOE lab (LLNL) and UC Davis have made a dielctric wall compact proton therapy machine. It is in the hands of the tomotherapy group which uses IMRT AND CT scans every treatment. They will lose business for every machine that sells. How long do you think before this new PRT machine will see the light of day?