In 2011, over the objections of some residents opposed to a nuclear facility in the town, the council authorized $1.53 million to buy 84 acres of farmland, which it has agreed to turn over to Shine for $1. The city has also agreed to pay $345,000 to extend utilities to the site, provide $2 million in forgivable loans and co-sign a bank loan with Shine up to $4 million that it would have to pay should the company fail, a first for the city.

Gale Price, economic development director for the city of Janesville, said that although it was unusual to put public money into a start-up, the city expected to recoup its investment within 10 years. “That’s how we measure whether we’re giving away the farm,” he said.

Mr. Ryan has championed the project and spoke at a celebration marking nuclear regulatory approval. But Mr. Piefer said, except for the initial phone call urging him to come to Janesville, Mr. Ryan has played no part in the federal grant and construction approvals.

Shine jumped at the chance at federal money for the private plant. But Mr. Piefer isn’t solely focused on the need in American hospitals. The company has already announced lucrative deals to ship moly-99 to Chinese hospitals.

But first, it needs to start producing.

“You cannot just open a shop down the street and start nuclear medicine,” said Dr. Iagaru, of Stanford Hospital. “The public comes with an expectation that if my oncologist wants me to get a bone scan, it’s not big deal,” Dr. Iagaru said. “But the truth is, it’s a big deal.”