DETROIT, MI -- When fraud accusations against Farid Fata were first brought to the attention of federal authorities, U.S. Attorney Barbara McQuade figured it was a case of opposing opinions on complex medical protocols.

"When we heard about the harm in this case, it was hard to believe," McQuade said.

"I imagined we were going to show these records to an expert who would say, 'Well, it's more aggressive than I would be, but it's within the reasonable bounds of reasonable medical care.' In fact, quite the opposite."

It would end up being the "most serious fraud case in the history of the country," according to the U.S. Justice Department, in terms of the scope and the severity of harm caused to hundreds of ailing patients.

Four days after an office manager at Fata's practice, George Karadsheh, tipped off federal investigators on Aug. 2, 2013, agents shut down his clinics, executed search warrants, interviewed employees and arrested the Michigan doctor.

Investigators eventually found that patients who were given false cancer diagnoses and treated with abnormal dosages of dangerous chemotherapy drugs suffered organ damage, nerve damage, immune system depletion, lost teeth and other permanent ailments.

"These are not side effects that they will ever recover from," McQuade said.

"Other patients actually did have cancer. Some were terminal. Chemotherapy was pointless. But he prescribed chemotherapy for them anyway, because it was profitable to do that."

Still others were given oddly small chemotherapy dosages, according to oncology experts who testified this week in the Michigan doctor's sentencing hearing.

"He underdosed other patients because he was too cheap to give them the amount of medicine they actually needed," McQuade said. "If they needed 1.25 vials of chemotherapy, instead he just gave them one. Because he didn't want to open up that second vial. It cost him too much money."

After hearing from two cancer experts and 20 victims and relatives of former patients over four days, U.S. District Judge Paul Borman on Friday sentenced Fata 45 years in federal prison, and ordered him to pay $17.6 million in restitution.

Fata, who ran clinics in the Detroit area and Lapeer County, pleaded guilty to health care fraud, money laundering and conspiracy to defraud the U.S. back in September 2014.

He ultimately admitted to some form of mistreatment in 553 separate cases.

Fata sobbed before the court as Borman prepared to issue his sentence Friday.

"Last Tuesday, (when victims spoke in court) I could not look (at) my patients and their families. Because I was horribly ashamed of my conduct," Fata said in between heaving emotional cries.

"It all went wrong. I cannot bring back the past. ... I have violated the medical oath, and I have caused anguish. ... I do not know how I can heal their wounds. I do not know what to do to express my sorrow and shame. Yes, I have accepted responsibility and admitted I am wrong. I did not feel I deserved a trial. I misused my talents and permitted this sin to enter me because of power and greed. My quest for power is self-destructive."

Fata, dressed in a black suit with no tie, glasses and a shaved head, sat stoically through most of his sentencing hearing, staring forward and away from victims when they spoke, until finally breaking down with emotion Friday when his lawyer told the court: "He has lost everything."

"He has lost his medical licenses in Pennsylvania and Michigan," said defense attorney Christopher Andreoff.

"He has lost his family. His wife and his children have moved from the United States. There are no people who have been visiting him for the last ... year and a half. We (his lawyers) have been his only visitors."

Fata agreed to forfeit $9.1 million from 15 different bank accounts, a Clarkston home worth $1.4 million, an Acura SUV, two life insurance policies and his interests in 11 different business entities.

McQuade said authorities planned to provide funds collected by the federal government to Fata's victims.

The whistleblowers who sparked the investigation are also entitled to some of the cash, McQuade said.

A group of victims and relatives of former patients wore yellow in court Friday.

They said it symbolized sunshine, which, they hoped, Fata would never see again.

Maggie Dorsey did not appear to draw much relief from from Fata's sentencing.

After leading a group of 20 victims and relatives of former patients in a Tuesday series of court statements on the impact of Fata's fraudulent care, Dorsey stood outside the courthouse with a stoic expression once the sentence was issued.

"I don't know," she said, shaking her head when asked her reaction to the 45-year prison term.

She wore a protective glove as a result of severe neuropathy suffered after Fata treated her with chemotherapy for multiple myeloma.

She never actually had multiple myeloma.

Dorsey made an intense emotional statement earlier in the week about losing the ability to comb her daughter's hair, to eat with metal silverware and, on some days, to simply stand.

Her daughter finished reading her statement to the court after Dorsey broke down with tears.

But her expression was blank, Friday.

"I was hoping for over 50, but it is what it is," she said. "Judge Borman was fair."

More coverage of the case here.