Summary
The cost of proton beam installations is massive, and is not justified in light of available litterature regarding the superiority of this therapy. There are only a handful of tumors, such as chordoma, where the proton beam therapy is recommended over other types of radiation. The higher compensation for this radiation is probably playing a part in the decision making for these new projects.
Analysis
I do not believe that companies such as Varian, Elekta, Phillips, and Accuray have to worry about competition from proton beam facilities.
The number of proposed centers is still quite small in the big scheme of things.
In addition, the technology of external beam therapy and radiosurgery is rapidly advancing, which will further diminish any theoretical advantage of proton beam therapy.
