Last February, Northern Illinois University won state permission to build an expensive and advanced proton-therapy cancer-treatment center in the suburb of West Chicago. It would be the first such facility in Illinois, joining five other centers in the nation.

But it won’t be the last: Proton therapy has a bright future. Doctors say it’s often superior to X-ray treatment: Its energy can be more finely focused on a cancerous tumor, sparing surrounding tissue to a significant degree. So far, it’s been used most often on children and patients with brain tumors.The promise of proton therapy explains why several more centers are in planning or construction stages nationwide—including one proposed by Central DuPage Hospital for Warrenville, about six miles from the NIU facility.

And that’s too close, according to the Illinois Health Facilities Planning Board. In April, the board issued a preliminary rejection of Central DuPage’s plan to build.