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Final decision on treatment: Viewray or Truebeam?
Prostate Cancer | Last Active: Apr 18 7:04am | Replies (34)Comment receiving replies
ViewRay is photon. The issue also has to do with how many beams. MRIdian has up to 18 beams, energy divided into 18 paths. Photon has all the energy through only two paths. As a result there are more skin burns with proton. Proton also adds 5 mm margins around tumors, MRIdian adds 3mm so less normal tissue is exposed with MRIdian. Adaptive radiotherapy and automatic gating significantly lower the risk of side effects with MRIdian which is about 50% less than other CT guided radiotherapy. There are no well designed randomized studies comparing proton with photon. No evidence that 45 proton sessions will do better than 5 with MRI-Linac.
Replies to "ViewRay is photon. The issue also has to do with how many beams. MRIdian has up..."
I think you intended to say "Proton has all the energy through only two paths." What I want to know is whether the Photon radiation is controlled by MRIdian so that it does not escape outside of the prostate when the beams are turned ON? From what I've read, Photons (xrays) pass right thru tissue and don't stop until they leave the body. What is your understanding as to what is going on when treatment is being applied ?
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Great summary. Although I chose 5 treatment proton at Mayo Rochester where they use Hitachi kit, the statement, "There are no well designed randomized studies comparing proton with photon" is consistent with all I have read and been told by urologists and radiologists. The one statement made by those perfming the procedure that I question is whether Radical Prostectomy is still the "Gold Standard". Photon and Proton have been shown to have equal long term outcomes.