@ava11 It is not MRI guided proton treatment but MRI of prostrate to align radiation treatments.

What I had was a low dose xray that looked at my gold markers put into my prostrate. This allowed the radiation treattment tech to align the proton device to target the radiation to the prostrate. And many times they did adjust my position and proton device to align with the prostrate parameters.

When they move the proton gantry to the other side of my body (this is done with gantry moving over you) they again do an xray to make sure the prostrate and body position is correct for the parameters for treatment. The xray is not on during treatments but before and after. The prostrate can move from one treatment to another and even between the left entry and right entry time proton radiation is being done.

What my post referred to was instead of using a low dose xray the poster was saying their check and adjust were done using a MRI to set up the paramaters for the proton treatment.

I cannot have a MRI to set up my parameters each time as I have a ICD/Pacemaker and have to take special precautions when having an MRI. I did have a MRI when doing MRI of prostrate to determine suspicious areas. In that case they turned off my pacing of my ICD/Pacemaker. Even doing the lose dose xray and proton radiation they required me to get a check of my ICD/Pacemaker once a week and send results to them to determine any interference with ICD/Pacemaker from the radiation I was getting.

Hope that answered. I have read that some photon (not proton) radiation uses MRI guided during the treatments but have not seen a specific one that mentioned proton. Don't know if out there but sure would be a plus if it were for those unlike me with a AICD/Pacemaker.