A patient who was exposed to an overdose of radiation during a CT scan on Monday sued Cedars-Sinai Medical Center and the maker of the scanner.

Trevor Rees's lawsuit, filed in Superior Court, seeks class action status on behalf of the 206 patients who received radiation overdoses because of an equipment error that went undetected for 1 1/2 years.

The lawsuit claims the hospital's staff and the scanner's manufacturer, General Electric Healthcare, were negligent in performing the scans.

Hospital officials said the staff reset the machine's computer to help doctors see blood flow in the brain and better diagnose strokes. However, "a misunderstanding about an embedded default setting applied by the machine" led patients to receive eight times the normal dose of radiation. About 40 percent of them lost patches of hair as a result.

Rees said the hair on his head and eyebrows fell out in the days and weeks following two CT scans in December 2008. He also experienced red and flaky skin on his face and scalp, symptoms of radiation overdose, he claimed.

Last month, hospital officials contacted him to ask if he had experienced any side effects following the scans, but was not told why, the lawsuit said.

Rees said the hospital did not inform him about the overdose.

Hospital officials have said that they had contacted all 206 patients who received the radiation overdoses.

GE has said the machine was not defective. A hospital spokeswoman Simi Singer said she has not seen the lawsuit and couldn't comment.

The suit also alleges medical malpractice, product liability and breach of warranty. It seeks general and economic damages.