Archive for December, 2013
Posted on December 18th, 2013 by Admin
From Mayo Clinic's Discovery's Edge magazine
Many prostate cancer survivors live in fear of being told that their cancer has returned. It’s even scarier to be told that the doctor knows the cancer is there because of rising PSA levels, but that he can’t find it. Doctors and patients alike know that early detection of the recurrent cancer is critical to the patient’s chance of beating it a second time.
The problem, however, is locating it.
A Mayo Clinic research team has developed a new imaging technique that can often find the recurrent disease months, if not years, earlier than other imaging techniques. Prostate cancer uses choline, a B-complex vitamin, as a building block. So when a minute amount of radioactively-labeled choline (choline C-11) is injected into a patient, it is quickly taken up by the cancer — like a fish rising to the bait.
The prostate cancer then emits radiation, allowing doctors to pinpoint its location. A positron emission tomography (PET) scanner is “able to tell where in the body this radiation is being emitted,” explains Mayo Clinic radiologist Val Lowe, M.D..
Choline C-11 isn’t toxic, and the radioactive element is so minimal, it’s really not much of a pharmacologic safety issue, explains Dr. Lowe. “If you take a grain of sugar and divide it into 100 pieces, one of those pieces is enough to do a PET scan.”
As well as being safe, the PET scan takes little time. Once the radioactive element is added to the choline C-11, it has a very short shelf-life. The half-life of choline C-11 is only 20 minutes, meaning it loses half of its radioactivity every 20 minutes. Because the radioactivity is the imaging agent that allows the PET scanner to see the cancer, the agent must be used shortly after it’s made. It cannot be stored and shipped. It essentially must be manufactured on-site.
All told, it takes about 45 minutes to make choline C-11, and the scan itself takes only about 20 minutes. The results are analyzed and a report is typically ready half an hour after the scan is completed.
“For the first time ever, we will have a clear blueprint of where the patient stands, at a far earlier course in treatment failure,” says Eugene Kwon, M.D., a Mayo Clinic urologist. “It has basically ripped the curtain off the Wizard of Oz.”
At this time, Mayo Clinic is the only health care provider in the country authorized to do this test. But when filing with the FDA, Mayo Clinic waived all exclusivity. It wanted other sites in the country to be able to manufacture and use the drug to better serve their own patients.
Posted on December 16th, 2013 by Jason Pratt
Posted on December 9th, 2013 by Admin
The blogs feature commentary from Mayo Clinic experts about most recent news and advances within each disease, specifically:
The content produced on these blogs is meant to spur discussion and our contributors look forward to answering any questions left in the comment section of blog posts or YouTube videos.
We also encourage our readers to use the comment section of posts to propose any topics they would like to see discussed in future posts.
Thanks for your continued interest and we look forward to expanding our collection of content focused on these conditions.
Posted on December 2nd, 2013 by Admin
From Mayo Clinic's Discovery's Edge magazine
Reducing radiation exposure from CT scans has become one of the primary goals of Mayo Clinic’s CT Clinical Innovation Center. Dr. Cynthia McCollough and her colleagues are doing the Radiation Limbo: How low can they go without sacrificing image quality.
Dr. McCollough is continually looking for ways to lower radiation exposures while maintaining the needed quality. A critical step in that process includes better defining what level of image quality is needed.
“We don’t always need pretty pictures,” says Dr. McCollough. “We only need pictures that clearly show the disease or injury. For some conditions, a really low exposure of radiation can be used.”
To reduce the amount of radiation patients are exposed to, the CT Clinical Innovation Center takes several routes. “The most basic, low-tech thing we can do is to ‘right-size’ the dose,” says Dr. McCollough.
Mayo Clinic has developed a computerized set of electronic protocols that are centrally managed. If an adjustment is made to a protocol, the correct, new information is instantly available at all 25 CT scanners on the Mayo Clinic campus in Rochester, Minn., as well as at all Mayo Clinic Health System sites, and the Mayo practices in Florida and Arizona.
Much like the automatic exposure feature on a camera, CT scanners can now automatically adjust the radiation exposure that the patient receives based on the type of exam and the size of the patient. “Everything we're doing with dose reduction is to make sure patients get the exams they need at the lowest radiation doses,” says Dr. McCollough.
One area where use of medical radiation has increased dramatically in recent years is in cardiology. It is also one of the areas that has seen significant decreases in the levels of radiation exposure. Dr. Charanjit Rihal, a cardiologist at Mayo Clinic, says the results have been encouraging. “We reduced the amount of radiation by at least 40 percent, and in some cases, by as much as 70 percent.”
Another of Dr. McCollough’s colleagues, Dr. Joel Fletcher a radiologist and the medical director of the CT Clinical Innovation Center, worked with the pediatric oncology group to lower the radiation dose for follow-up CT scans for children diagnosed with cancer who had completed treatment.
“We just kept turning down the dose until finally it was down to the lowest setting the scanner would run at,” says Dr. McCollough. With each setting, a pediatric radiologist would look at the scan to ensure that the image was still clear. “We try to do the limbo: you know, ‘How low can you go?’”
With education, new technology, and collaboration between physicists, radiologists, and other physicians, Mayo Clinic is answering that question.