Carbon Ion radiation therapy is available in some countries, but not the USA, according to this article.

"Globally, carbon ion therapy is viewed as the next horizon of cancer care. About 22,000 patients have received the treatment at 13 centers in Germany, Austria, Italy, Japan, and China. More locations are under development in South Korea, Taiwan, and France.

Yet the therapy has followed an odd trajectory in the US. Although it was developed in California in 1975 and early research pointed to its advantages, not a single carbon ion facility, not even a research-oriented one, exists in the US. Other countries invested public money in the technology, but so far, American proponents of carbon ions have been unable to garner federal construction money or sufficient private backing."