Brosig and 18 other people gave victim impact statements, both in person and through a prosecutor, describing their pain and hurt.
Barto's wife, Linda Barto, was among them.
"He has been lying to me about everything for all of the 52 years I have known him. ... He spent his whole sinister life lying and sneaking around, so he could carry on his abuse uninterrupted," she said.
She said her heart was heavy for the victims.
Authorities had a chance to stop Barto in 2000, when he appeared before the Pennsylvania Board of Medicine on administrative charges that he molested two young girls in the 1990s. But regulators threw out the case and allowed him to keep practicing medicine, saying the allegations were "incongruous to his reputation."
Barto was a beloved paediatrician in Johnstown — and an elected school board member — with hundreds of supporters who flatly disbelieved he was a paedophile.
Such was the community's support that ribbons were distributed and worn at a high school football game as he fought the allegations in the 1990s. Brosig, who felt obligated to wear the ribbon as a member of the colour guard, said it "burned a hole in my chest that entire night."
After the medical board cleared him, Barto felt "invincible," he later told authorities.
And he continued molesting.
Barto, now 71, went on to violate at least a dozen more young patients before his arrest in January 2018, according to the state attorney general's office.
"Dr Barto used his position of authority as a paediatrician, the family doctor relied on to treat and heal their children, to feed his own sick desires," Attorney-General Josh Shapiro said at a news conference after the sentencing.
In handing Barto a prison term of 79 to 158 years — meaning the ex-paediatrician will die in prison — a judge told the gathered victims that justice was finally theirs.
"All I can say is that the justice system is not perfect, but it worked the second time," Judge Patrick Kiniry said.
Barto did not apologise and declined to make a statement. He pleaded guilty in December to sexually abusing two family members. He pleaded no contest to the charges involving his patients, refusing to admit guilt but accepting the punishment.
His lawyer, David Weaver, said Barto would not appeal the sentence.
Even after Barto was charged last year, some people in the area still couldn't accept the truth about him, launching a Facebook group in support.
- AP