MIAMI, Fla. - Elderly Russian immigrants lined up to take kickbacks from the backroom of a Brooklyn clinic.

Claims flooded in from Miami for HIV treatments that never occurred. One professional patient was named in nearly 4,000 false Medicare claims.

Authorities said busts carried out this week in Miami, New York City, Detroit, Houston and Baton Rouge, La., were the largest Medicare fraud takedown in history - part of a massive overhaul in the way federal officials are preventing and prosecuting the crimes.

In all, 94 people - including several doctors and nurses were charged Friday in scams totaling $251 million. Federal authorities, while touting the operation, cautioned the cases represent only a fraction of the estimated $60 billion to $90 billion in Medicare fraud absorbed by taxpayers each year.

For the first time federal officials have the power to overhaul the system under Obama's Affordable Care Act, which gives them authority to stop paying a provider they suspect is fraudulent.

Critics have complained the current process did nothing more than rubber-stamp payments to fraudulent providers.