An $182 million below-ground cancer clinic is set to open in March on the Mayo Clinic's Phoenix campus.

The clinic will house Arizona's only proton beam therapy program, which tries to minimize damage to surrounding tissue during cancer tumor radiation.

The concrete facility is being built entirely with private donations and is expected to treat about 1,200 patients a year. The Arizona Daily Star reports about 40 percent of the patients will come from outside the Phoenix area.

Currently, the closest facilities for Arizonans seeking high frequency, targeted proton beam therapy are in California and Texas. 

Some critics contend the therapy has little benefit over X-ray radiation but supporters say it can reduce damage to surrounding healthy tissue by as much as 99 percent. They say it may be particularly helpful for kids with tumors close to critical organs.