2)  Some centers don't use balloons and others do.  Are their rates of success equal, better, or worse?

Impossible to answer this question because of the different times the facilities were activated. I will say that both LLUMC and MPRI do use the balloons, and LLUMC's success is established. (See PDF by Dr. Rossi in "Files."

I don't know which of the other centers do not use balloons except that some that went to the Florida Center said they did not have the balloon experience. I have no way of determining why they chose not to use the balloon, or if their method is better.  I would put this in the "To be determined" category.

I will say that the rationale for the balloon use is to distend the rectum so that most of the rectal tissue is well out of the beam path, and to "secure" the prostate gland against the pelvic wall to prevent movement during treatment (which only lasts about one or two minutes).

Anyone with answers about balloons for the Texas and Massachusetts proton facilities, or for any of these questions, please help.


3)  Do they all use real time imaging?

Real time imaging needs to be defined. If by real time imaging is meant imaging of the gland during the actual proton beam application, the answer is no. This will be the next generation of improvements, when active "pencil beam" scanning of the tumor or target will be utilized. probably a minimum of five years in the future; one of the planned new centers will probably be the first to incorporate this.
The system used by LLUMC, MPRI, and (I think) FPTI is to do a "master" CT Scan, then just before the beam application, with the patient in a positioning device, a radiograph (x-ray photograph like the standard chest X-ray) is made amd the patient position is carefully aligned so that the current gland location matches the master CT Scan. Then the beam is applied.


4)  Are there any other differences between the treatment provided at the various centers?

I am in hopes that this group will help to identify the differences in the various centers.

Very recent correspondence with a "graduate" of the MPRI Indiana Center identified a difference:
The total dosage is about the same as at LLUMC, but on each day of treatment, both a left hip AND a right hip treatment is done, such that the total that day is 1.8 Gy (one presumes 0.90 Gy through each hip).

Loma Linda's protocol is to deliver a 1.8 Gy dose through alternating left and  right sides on alternating days. In other words, for instance, on Monday a patient would receive a 1.8 Gy treatment on the right side, then on Tuesday the treatment would be 1.8 Gy through the left side.

There are differences in patient restraining devices (LLUMC uses a body cast "pod") and no doubt other differences in protocols, probably all minor.

Hopes this helps. What should be kept in mind is that the basic application should be about the same - 79-81 Gy total), and that the accuracy and the precision of the proton beam is far greater than standard radiation, and also results in less total integrated radiation dose to non-target body tissue even with the newest IMRT methodology.

Fuller