Cracking Down CT Radiation Dose Control by joq12180

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									Cracking Down: CT Radiation Dose Control



April 1, 2008
Cover Story
By Beth Walsh




Medical imaging procedures offer unprecedented abilities for physicians to detect, diagnose and
treat a wide range of diseases and medical problems. An estimated 68 million CT scans, for
example, are performed every year in the United States. That’s up from 3 million in 1980. Along
with the new capabilities, however, are new concerns about radiation exposure. The issue has
come to a head—from education and awareness to updated guidelines and equipment
advances.
Radiation dose awareness in imaging studies started a long time before the New England
Journal of Medicine (NEJM) published an article last November warning that the overuse of
diagnostic CT scans may cause as many as 3 million additional cancers in the United States
during the next two to three decades. That’s a risk the radiology community has been well
aware of for a long time. But the NEJM article revived the quest to control dose for patients and
clinicians. The challenge now is expanding that awareness to the rest of the medical community.

“The traditional approach to diagnostic testing can be characterized as ‘leave no stone
unturned’ to achieve the most certain diagnosis possible,” says David A. Schauer, ScD, CHP,
executive director of the National Council on Radiation Protection and Measurements. “Under
this philosophy, as long as an imaging examination has any chance at all of demonstrating a
diagnosis suggested by the clinical clues, then its use is considered reasonable.”

That approach doesn’t take into consideration the impact that any radiation involved in
treatment would have on the patient, he points out. “It is clear that breaking this habit and
beginning to link selection of patient for imaging examination to likelihood of effect on
treatment choice or on patient outcome can help to reduce the economic problems resulting
from imaging uses which now adversely affect healthcare costs and to reduce unnecessary
radiation exposure of the patient.”

The Alliance for Radiation Safety in Pediatric Imaging launched its new Image Gently campaign
in January, with the goal of raising awareness of the opportunities to lower radiation dose when
imaging children. At least 600 practices have already signed on and pledge to practice in
accordance with the campaign’s recommendation. The medical community has been extremely
receptive, says Donald Frush, MD, chair of the American College of Radiology (ACR) Pediatric
Imaging Commission.

“This was not taken on as a scare campaign or adversarial campaign,” he says. “It was always
based fundamentally on getting information out to practices, organizations and individuals.”
Essentially, the campaign is trying to do everything that the NEJM article did not, he says. That
includes spreading the word that “CT is really helpful, it saves lives and there are ways to do it
appropriately.”

Donald Frush, MD, chair of the American College of Radiology Pediatric Imaging Commission,
with a patient at the Duke University Medical Center in Durham, NC.

Frush says there has been a growing interest over the past six or seven years to look at
radiology’s effects specifically in children and young adults. Some of the cancers that the NEJM
article predicted are related to radiation. Since they can take 30 years to develop, excessive
exposure to radiation is especially important when imaging children. A two-year-old, for
example, has a much higher chance of a 75-year-old of developing one of these cancers. Plus,
children are more radiosensitive because their tissues and organs are still dividing and growing.
“That kind of tissue has more of a chance of having effects from radiation than tissue simply
repairing itself like an adult’s,” he explains.

Radiologists who specialize in pediatric radiology understand the need to image children
differently, says Priscilla F. Butler, MS, senior director, Breast Imaging Accreditation Programs
for the ACR, who also was involved in the Image Gently campaign. Most pediatric imaging in the
United States, however, is done at community hospitals that probably don’t have a pediatric
radiology specialty. “The whole purpose of the initiative was to raise awareness among the
radiologists who don’t do as many pediatric patients.”

The campaign has enjoyed “extremely positive feedback,” she says. “Techs feel empowered to
bring issues to radiologists. This has been a joint effort among the different players in the
radiology department—technologists, radiologists and medical physicists.” Based on the positive
response, the ACR is working on an educational campaign for referring physicians and patients
and families. “We have to be careful,” she says. “We don’t want to scare people off from having
important, life-saving exams. But, we’re dealing with medicine. With everything we do, there is
some risk.”

Many opportunities
________________________________________
It’s hard to determine how much effort is enough, Frush says, but “there is a lot of work that can
be done on all fronts,” including academia, equipment manufacturers, private practice,
physicists and the media. “There are a great many opportunities to get information to people
about how to [image] better. Many manufacturers are very sensitive to this issue and want to
behave and practice as advocates for patients.”




Donald Frush, MD, chair of the
American College of Radiology
Pediatric Imaging Commission,
with a patient at the Duke
University Medical Center in
Durham, NC

Frush notes that over the past several years, “there has been a tremendous reception on many
[CT system] manufacturers’ part to make both image quality and dose part of their marketing. I
applaud them for that.”

Vendors have been working with individual institutions on new software, procedures and
equipment design to minimize radiation dose, says Butler. The development in CT has been
amazing, she says. “Not all that long ago, there wasn’t a way to automatically vary radiation
depending on patient size.” Overall, vendors have been very supportive regarding the control of
radiation dose. Efforts such as making dosage information available in their DICOM header have
helped to increase physician awareness.
More can be done, however. “I think that there should be automated systems that make sure
that the radiation that is delivered is the least that is feasible,” says Daniel Rosenthal, MD,
associate radiologist-in-chief at Massachusetts General Hospital. He would like to see all CT
scanners be obligated to report radiation doses in a unified, uniform system so doses can be
compared. That would be particularly valuable in follow-up situations, for example, where the
recent radiation exposure would allow for a second scan of equal quality at a lower dose.

Imaging is a victim of its own success, to some degree. “Imaging has gotten so spectacular, it’s
hard for clinicians not to order an imaging study,” says Rosenthal. Redundant and unnecessary
exams really need to be controlled, however. “This sort of promiscuous ordering of imaging
studies is probably not in patients’ interest.”

Aside from the large CT system vendors working on imaging techniques that reduce radiation
exposure while maintaining high image quality, smaller companies also are making inroads on
radiation dose control. Rosenthal helped developed RadPort, now distributed by Dictaphone.
RadPort helps radiologists determine which exams should be ordered based on a patient’s
symptoms. It is based on a set of 1,100 rules that were developed (from the original 200 that the
American College of Radiology uses) by Massachusetts General Hospital.

RadPort is helping to reduce the number of inappropriate exams that are ordered, and make
sure the right exams are ordered the first time so problems can be diagnosed sooner, treatment
can begin sooner and patients aren’t exposed to unnecessary amounts of radiation. In addition,
RadPort pre-qualifies exams for insurance coverage, so it helps eliminate problems on the payor
end of things as well.

RadPort’s decision support is an effort to increase the appropriateness with which x-ray exams
are used, says Rosenthal. A user selects an exam, enters one or more reasons for the exam and
then the system feeds back a score to help the user rate the appropriateness of the study and
determine whether it is highly indicated. RadPort also offers comparative scores for other,
similar exams, some of which do not involve radiation at all.
RadPort takes a very complex calculation and reduces it to a series of rules that will not always
be right, Rosenthal admits. “We’ve tried to apply an algorithmic approach, with understanding
by users that this is for general case. There will be exceptions.” Once users are accustomed to
the system, it results in “very distinct changes in practice initially,” he says. Users first find the
system indicating a high rate of use of exams it considers inappropriate. Over time, that usually
drops to about 2 percent of all exams.

Another player in this field is RCG HealthCare Consulting, which offers RadOPS-CT, a service that
helps practices reduce radiation dosage for patients undergoing CT exams. The service assesses
current CT exam practices and protocols, develops a radiation exposure profile, delivers new,
optimized CT protocols proven to markedly reduce patient dose, provides training and support
for technologists and radiologists, and monitors periodic dosage results to identify further
opportunities for refining the overall process.

On average, the radiation exposure service reduces exposure by up to 60 percent, according to
Dushyant Suhani, MD, director of CT radiology at Massachusetts General Hospital, where the
technology was developed. By reviewing protocols that can reduce exposure without sacrificing
quality, facilities can focus on improving quality and increasing patient safety. “It’s valuable to
measure radiation exposure and it’s good operations to measure exposure,” David Charpie, RCG
executive director.
Although the issue is quite complex, the confluence of technology, protocol, workflow and other
strategies plays a significant role in reducing unnecessary radiation exposure.

The service lets RCG help practices that don’t have the same resources. “We see this as a
journey, not a product we drop on them.” That includes creating and setting up protocols for
most clinical indications so that technologists don’t have to do a lot of technical changes in
parameters for each patient.

On the horizon
________________________________________
Controlling radiation dose is “very vexing,” says Rosenthal. Beyond patient safety, there are
financial considerations. Studies have shown, he says, that up to 30 percent of imaging studies
are unnecessary. Healthcare expenditures are steadily creeping up to almost 20 percent of the
U.S. gross national product, and imaging has been growing in double-digit numbers for several
years. “It’s unrealistic, however, to think that imaging will become flat or reverse because
imaging is growing more powerful and useful in medicine. It has to be brought down from a
raging bonfire to a little flame.”

The focus on controlling radiation dose probably will face “consistent and growing interest,”
says Charpie. “I think there’s going to be a continuing pace to it.” That pace is dependent on the
time and resources organizations can put against the problem, he says.

Beyond the organizational level, physician organizations, physicists, equipment manufacturers,
professional groups and even the federal government will play a role, says Suhani. He likens the
situation to that of global warming. “There is no single strategy that is going to work and they
will happen at multiple levels.” In the next few years, he “envisions that each and every site in
the world will have a better approach.”



 ‘Child-size the Dose’ The Image Gently Campaign

 Among the new guidelines of the Image Gently campaign launched by the Alliance for Radiation
 Safety in Pediatric Imaging are:

 Significantly reduce, or “child-size,” the amount of radiation used

 Do not over-scan

        Scan only when necessary
        Scan only the
        indicated region
        Scan once; multi phase scanning (pre-and post contrast, delayed exams) is rarely helpful

 Be a team player

        Involve medical physicists to monitor pediatric CT techniques
       Involve technologists to optimize scanning

For more details, visit: ImageGently.org and www.ajronline.org/cgi/content/full/190/2/273. To
develop CT protocols for children, visit: www.pedrad.org/associations/5364/files/Protocols.pdf

								
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