Ct Scans

More than 200 patients at Cedars-Sinai Medical Center were inappropriately exposed to high doses of radiation from CT brain scans used to diagnose strokes, hospital officials told The Times on Friday. About 40% of the patients lost patches of hair as a result of the overdoses, a hospital spokesman said. Even so, the overdoses went undetected for 18 months as patients received eight times the dose normally delivered in the procedure, raising questions about why it took Cedars-Sinai so long to notice that something was wrong.

Noninvasive CT scans are nearly as accurate at imaging coronary artery blockages as conventional angiography and are much safer for many patients, according to researchers who published a study today in the New England Journal of Medicine. Angiograms are considered the gold standard for detecting blockages in the arteries.

Doctors might be overusing CT scans, the popular diagnostic tool that exposes patients to far more radiation than conventional X-rays, scientists in Manhattan will report today. The analysis by investigators at Columbia University Medical Center comes on the heels of another released this week by researchers at Brown University, who found pregnant women are being exposed to twice the amount of radiation through CT scans as they were in 1997.

To screen or not to screen? That is the question patients -- most of them current or former smokers -- are asking doctors following the publication of a large international study that found that spiral CT scans can detect lung cancer at its earliest and most curable stage. The results, published last month in the New England Journal of Medicine, have fueled hope that the technology can lead to early treatment of the most common cause of cancer death, as mammography has done for breast cancer.

Larry Ewing's life changed last year on a construction site in Victorville; Larry Carr's changed in 2004 on a road in Iraq. Unlikely brothers in arms, both men now share the same invisible wound -- traumatic brain injury. They tire easily, forget often and lose their balance and concentration without warning. They struggle to make peace with personality changes that have made them barely recognizable to loved ones. And they -- like millions of brain-injured civilians, and hundreds of thousands of troops whose brains have been jolted by blasts in Iraq and Afghanistan -- find that their best hope for better diagnosis and care comes from military medicine.

Every time a patient receives a CT scan, a mundane array of numbers appears on a computer screen before a technician. The numbers include the radiation dose. "It's in your face on the screen," said Dr. Donald Rucker, chief medical officer for Siemens, a manufacturer of CT scanners. Beginning in February 2008, each time a patient at Cedars-Sinai Medical Center received a CT brain perfusion scan -- a state-of-the-art procedure used to diagnose strokes -- the dose displayed would have been eight times higher than normal.

Cedars-Sinai Medical Center did not tell all 206 patients who received radiation overdoses during CT scans of the hospital's error, according to the accounts of four people who said they only came to understand what happened to them through news reports. In a statement last week, hospital officials said all the patients had been contacted "in the interest of keeping them informed." But in interviews with The Times, four people said that although they were called and questioned by Cedars-Sinai radiologists last month, the doctors neither acknowledged any error nor explained that the patients had been exposed to eight times more radiation than necessary.

Americans may be receiving too much radiation from medical tests whose value has not been proven, researchers reported in the New England Journal of Medicine. More than two-thirds of Americans underwent at least one such imaging procedure in the three years covered by the study, reported Dr. Reza Fazel and colleagues at Emory University School of Medicine in Atlanta. The two biggest contributors to the radiation exposure are CT scans, which use a series of X-rays to produce a three-dimensional image of the body, and heart perfusion scanning to measure blood flow through the arteries leading to the heart.

Six mummies and other Egyptian artifacts arrived in Santa Ana this week for a two-year exhibit at the Bowers Museum. And they made their debut in the parking lot. In an effort to publicize the upcoming exhibit, museum officials had the mummies CT-scanned in a truck just outside the building. On Thursday, museum officials repeated the drill for the news media, pointing out the machine wasn't actually scanning at that time.

CT scans can cut the number of unnecessary appendectomies performed in hospitals from 20% to 3%, researchers from Massachusetts General Hospital report this month in the American Journal of Roentgenology. Prior to the use of CT scans, there was no good way to determine whether appendicitis was present, the team said. But the sophisticated X-ray scans are good at imaging the appendix as well as finding conditions that mimic appendicitis.