RadNet Inc., which operates a network of diagnostic-imaging outpatient centers, on Tuesday said that it wants to borrow as much as $455 million to refinance its debt.

The Los Angeles company said it plans to pay off a term loan and a portion the existing balance on its revolving credit line with as much as $330 million in term loans. It also is seeking a new revolving loan of between $100 million and $125 million.

RadNet, which operates 237 imaging centers primarily in California and five other states, on June 30 had about $338 million of loans outstanding, including $279 million of term debt and $59.5 million under its revolving facility, the company said.

Shares closed up 12 cents, or 4.4 percent, to $2.85 on the Nasdaq.