September 05, 2013
Ever since a few high-profile stories put CT dose under the media microscope in 2009, dose scrutiny has spilled over into other modalities — namely molecular imaging. Both governmental agencies like the Food and Drug Administration and the public have consequently expressed more interest in the topic.“In Boston Children’s Hospital, I see parents asking more questions about radiation, its risks, and what it means for their child,” Dr. Frederic Fahey, past president-elect of 2012 at the Society of Nuclear Medicine and Molecular Imaging (SNMMI), told DOTmed News. Indeed, concern around radiation dose is commonly cited as one of the barriers to growth in the molecular imaging market.Recognizing that dose awareness in molecular imaging is in its relative infancy, Fahey and colleague Dr. Adam Alessio, associate professor at the Imaging Research Laboratory at the University of Washington and Fahey’s co-chair for the SNMMI Dose Optimization Working Group, endeavored to organize initiatives during Fahey’s presidency that would help move dose awareness forward in the field.Ultimately, the organization’s goal is to help provide practitioners with as much information on dose optimization as it can — a goal that’s easier said than done, since there are some logical hurdles to overcome around collecting that information.For good measureFor example, SNMMI recently worked with the Intersocietal Accreditation Commission (IAC) to help do something that had been only done on a smaller scale before: collect data to see how much levels of radiation dose varied from center to center for the same scan — more specifically, PET and bone scans.The society gathered and analyzed data submitted to the IAC from sites seeking accreditation — a total of 225 sites that performed MDP bone scans and 95 sites that performed FDG PET scans.

Though on average the median levels of radiation dose fell squarely in line with the levels recommended by the society, there was significant individual variation. On the bone scan side, one patient received 19 millicuries of radiation for another patient’s 36. And the radiation levels for PET scans ranged from 3 to 23 millicuries, though the suggested range is 10-20.

Fahey cautions that the data might be biased, since centers that seek accreditation might be more scrupulous in their dose administration than centers that don’t, but the study is still the largest review of its sort.

Manual labor

On the manufacturing end, CT dose reduction efforts have been met with measurably significant success, as there’s been a big market to satisfy increased demand for lower dose technologies. But whether this momentum will translate over to molecular imaging is questionable.


“It’ll be more of a challenge on the nuclear medicine side because we’ve been trying to administer the minimum dose all along. I don’t think we’ll see factor of 10 dose reduction — more like factor of two,” said Fahey.

Furthermore, data is really the key to understanding how to use dose correctly, but collecting it is a particular challenge for the molecular imaging industry.

Unlike CT, where dose levels are automatically recorded in the scanner in the DICOM header and sent to the ACR National Radiology Data Registry, the biomarkers, or the radioactive component of molecular scanners, are injected by technologists into patients.

This means that the dose data is recorded manually by the technologist into an online log, or sometimes even on paper or in a book, meaning that there’s much more difficulty sending that data over to the proper channels to be analyzed.

“In the ACR dose registry, nobody’s having to type or write anything,” said Fahey. “It’s easier to fix things when you know exactly what you’re doing.”

Global bridges

Finally, the society has developed a global initiative involving 12 other nuclear medicine societies around the world, including national organizations from Japan, Korea, China, Australia, South Africa, and Canada.

Its first project was pediatric dose optimization, which builds on the Image Gently campaign to raise awareness on dose optimization across different countries.

Due to its recent radiation scare in 2011, Japan, which has one of the largest imaging markets in the world, has seen a surge of focus on dose reduction, spurring practitioners in the country to proactively seek out and develop guidelines to keep dose at a reasonable level.

The SNNMI is also interested in working closely with societies in Europe to develop better dose guidelines and protocols.

“They came out with their pediatric dose statement in 2007 and we came out with ours in 2011. By 2014 they will be pretty much the same, which is a good thing,” said Fahey.


No comments

Be the first one to leave a comment.

Post a Comment