France - CT scans in childhood increased cancer risk, says study

PARIS: Children exposed to multiple CT scans could be up to three times likelier to contract cancer of the blood, brain or bone marrow later in life, according to research published on Thursday.

Writing in The Lancet medical journal, a team of scientists in Canada, Britain and the United States said the cancer risk, in absolute terms, appears to be small.

But they appealed for radiation doses from CT scans to be kept at a minimum and for alternatives to be used where appropriate.

The researchers claimed their study was the first to provide direct evidence of a link between exposure from CT radiation in childhood and later cancer risk.

"Of utmost importance is that where CT is used, it is only used where fully justified from a clinical perspective," said lead author Mark Pearce of Newcastle University's Institute of Health and Society.

As a vital diagnostic technique, use of the CT scan has increased rapidly in the past 10 years, particularly in the United States, the researchers said.

"However, potential cancer risks exist due to the ionising radiation used in CT scans, especially in children who are more radiosensitive than adults."

Computerised tomography - commonly known as CT - is an X-ray technique that produces images of the body's internal structures in cross sections.

The researchers studied nearly 180,000 people who underwent a CT scan as children or young adults (under 22) in Britain between 1985 and 2002.

Of these, 74 were subsequently diagnosed with leukaemia and 135 with brain cancer according to data for the period 1985 to 2008.

The team calculated that compared to patients who received a radiation dose of less than five milli-Grays (mGy), those who were given a cumulative dose of 30 mGy had about three times the risk of developing leukaemia (cancer of the blood or marrow) later in life.

Those who received 50 to 74 mGy had thrice the risk of brain tumours.

The study did not compare children who had been scanned against those who had not been scanned.

Put into context, this means that among every 10,000 patients who received one CT scan before the age of 10, there would be one extra case of leukaemia and one extra brain tumour per 10 mGy of radiation in the 10 years after exposure.

"Further refinements to allow reduction in CT doses should be a priority, not only for the radiology community, but also for manufacturers," said Pearce.

"Alternative diagnostic procedures that do not involve ionising radiation exposure, such as ultrasound and MRI (magnetic resonance imaging) might be appropriate in some clinical settings."

Commenting on the study, Andrew Einstein of the Columbia University Medical Centre in New York said Pearce and his colleagues' work confirmed that CT scans "almost certainly produce a small cancer risk".

"Use of CT scans continues to rise, generally with good clinical reasons, so we must redouble our efforts to justify and optimise every CT scan."

- AFP/de

USA - Small 'neural focus groups' predict anti-smoking ad success

Brain scans of a small group of people can predict the actions of entire populations, according to a new study by researchers from the University of Michigan, the University of Oregon and the University of California at Los Angeles.

The findings are relevant to political advertising, commercial market research and public health campaigns, and broaden the use of brain imaging from a diagnostic to a predictive tool.

As opposed to the wisdom of the crowd, the study suggests that the neurological reactions of a few—reactions that people are not even consciously aware of and that differ from the opinions they express—can predict the responses of many other people to ad campaigns promoting specific behaviors.

"Brain responses to ads forecasted the ads' success when other predictors failed," said Emily Falk, director of the U-M Communication Neuroscience Lab and lead author of the study, which appears online in Psychological Science.

"Our findings could help design better health campaigns. This is a key step in reducing the number of smokers and reducing deaths from cancer, heart disease and other smoking-related illnesses."

The findings, she said, might also help produce more effective political campaign ads and provide a neural roadmap to why some videos, fashions, behaviors and ideas go viral, moving from one person to many thousands of others via social media.

Falk conducted the study with Elliot Berkman of Oregon and Matthew Lieberman of UCLA. The researchers were supported by the National Science Foundation and the National Institutes of Health.

For the study, the researchers recruited 31 heavy smokers with a strong desire to quit, and examined their neural responses to three anti-smoking ad campaigns, using functional magnetic resonance imaging (fMRI). All of the ads directly urged viewers to call the National Cancer Institute's tobacco quit-line (1-800-QUIT-NOW).

Following the fMRI, participants rated the effectiveness of the ads they had just viewed in a variety of ways. The researchers compared their brain scans to their reports on the ads' effectiveness.

To obtain population-level measures, the researchers compared the number of calls to the tobacco quit-line in the month before and after each media campaign first aired in three different media markets.

When asked what they thought of the ads, participants rated Campaign B the highest, followed by Campaign A and then Campaign C. Industry experts familiar with the campaigns also disliked Campaign C. The three campaigns used very different strategies. Raters found Campaign C annoying and guessed that it would be ineffective. By contrast, Campaigns A and B resonated with participants, but in the end were less effective in actually driving calls to 1-800-QUIT-NOW.

But brain scans, which focused on the medial pre-frontal cortex, an area of the brain identified in earlier studies as linked to positive responses to persuasive messages, showed a completely different order, with Campaign C eliciting the strongest response.

At the population level, each ad campaign led to increases in call volume to the quit-smoking line, compared with a no-media control month before the launch of each campaign. The increases ranged from 2.8 times to 32 times higher than the control month, and the researchers found that Campaign C led to the highest increases, followed by Campaign B and lastly Campaign A—just the opposite of the participants' guesses but precisely the same as their brain scans showed.

"It seems that the brain is picking up on important features of these ads, but we're not sure what these features are yet," said Falk, assistant professor of communication studies and a faculty associate at the U-M Institute for Social Research. "We're doing follow up studies now to translate what the brain is telling us about how to design better messages."

This study broadens the use of neuroscience data from predicting individual behavior to predicting the responses of much larger groups of people.

"It seems that the brain can predict the responses of entire populations to ad campaigns," Falk said. "The behavior of people whose brains are never examined may be inferred from the brains of a small 'neural focus group.'

"These findings could help us improve the success of campaigns. In the long run, we hope this will help us fight cancer and other preventable diseases."

More information: Falk's Communications Neuroscience Lab: http://cn.isr.umic … u/index.html

Berkman's Social and Affective Neuroscience Lab: http://sanlab.uore … SAN_Lab.html

Lieberman's Social Cognitive Neuroscience Lab: http://www.scn.ucla.edu

Provided by University of Michigan (news : web)

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UK - Scientists develop new technique that could improve heart attack prediction

An award-winning research project, funded by the British Heart Foundation (BHF), has tested a new imaging method which could help improve how doctors predict a patient's risk of having a heart attack.

Scientists from the University of Edinburgh, a BHF Centre of Research Excellence, in collaboration with the University of Cambridge are the first to demonstrate the potential of combining PET and CT scanning to image the disease processes directly in the coronary arteries that cause heart attacks.

There are nearly 2.7 million people living with coronary heart disease (CHD) in the UK and it kills 88,000 people each year. Most of these deaths are caused by a heart attack. Each year there are around 124,000 heart attacks in the UK.

The research, published in the Journal of the American College of Cardiology(JACC), involved giving over 100 people a CT calcium score to measure the amount of calcified or hardened plaques in their coronary arteries. This is a standard test, which is commonly used to predict CHD risk but cannot distinguish calcium that has been there for some time from calcium that is actively building up.

The patients were also injected with two tracers, special molecules that show up on certain imaging scans and can be used to track substances in the body.

One of these tracers, 18F-sodium fluoride (18F-NaF), is a molecule taken up by cells in which active calcification is occurring. The 18F-NaF can then be picked up and measured on PET scans.

The researchers wanted to see if they could identify patients with active, ongoing calcification because these patients may be at higher risk than patients in whom the calcium developed a long time ago.

The results showed that increased 18F-NaF activity could be observed in specific coronary artery plaques in patients who had many other high-risk markers of cardiovascular disease.

Dr Marc Dweck, lead author on the research paper and a BHF Clinical Research Fellow at the University of Edinburgh, said:

"Predicting heart attacks is very difficult and the methods we've got now are good but not perfect. Our new technique holds a lot of promise as a means of improving heart attack prediction although further ongoing work is needed before it becomes routine clinical practice.

"If we can identify patients at high risk of a heart attack earlier, we can then use intensive drug treatments, and perhaps procedures such as stents, to reduce the chances of them having a heart attack."

Dr Shannon Amoils, Research Advisor at the (BHF), which funded the study, said:

"For decades cardiologists have been looking for ways to detect the high-risk plaques found in coronary arteries that could rupture to cause a heart attack, but it's been difficult to develop a suitable imaging test that can focus in on these small vessels.

"This research is a technical tour de force as it allows us to assess active calcification happening right in the problem area – inside the wall of the coronary arteries and this active calcification may correlate with a higher risk of a heart attack."

The research follows on from recent work Dr Dweck did using PET/CT that provided greater insight into the aortic valve disease – aortic stenosis. With the support of the BHF, Dr Dweck and his colleagues at Edinburgh also intend to translate this technique into predicting a patient's risk of a stroke.

More information: Dweck M et al (2012). Coronary arterial 18F-Sodium Fluoride Uptake. Journal of the American College of Cardiology. Currently available online: http://content.onl … t/59/17/1539

Information about this research is available here: http://www.bhf.org … x?page=14021

Provided by University of Edinburgh (news : web)

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USA - Brain scans can predict weight gain and sexual activity: study

At a time when obesity has become epidemic in American society, Dartmouth scientists have found that functional magnetic resonance imaging (fMRI) brain scans may be able to predict weight gain. In a study published April 18, 2012, in The Journal of Neuroscience, the researchers demonstrated a connection between fMRI brain responses to appetite-driven cues and future behavior.

"This is one of the first studies in brain imaging that uses the responses observed in the scanner to predict important, real-world outcomes over a long period of time," says Todd Heatherton, the Lincoln Filene Professor in Human Relations in the department of psychological and brain sciences and a coauthor on the study. "Using brain activity to predict a consequential behavior outside the scanner is pretty novel."

Using fMRI, the researchers targeted a region of the brain known as the nucleus accumbens, often referred to as the brain's "reward center," in a group of incoming first-year college students. While undergoing scans, the subjects viewed images of animals, environmental scenes, appetizing food items, and people. Six months later, their weight and responses to questionnaires regarding interim sexual behavior were compared with their previously recorded weight and brain scan data.

"The people whose brains responded more strongly to food cues were the people who went on to gain more weight six months later," explains Kathryn Demos, first author on the paper. Demos, who conducted the research as part of her doctoral dissertation at Dartmouth, is currently on the research faculty at the Warren Alpert Medical School of Brown University.

The correlation between strong food image brain responses and weight gain was also present for sexual images and activity. "Just as cue reactivity to food images was investigated as potential predictors of weight gain, cue reactivity to sexual images was used to predict sexual desire," the authors report.

The paper stresses "material specificity," noting that the participants who responded to food images gained weight but did not engage in more sexual behavior, and vice versa. The authors go on to say that none of the non-food images predicted weight gain.

Heatherton and William Kelley, associate professor of psychological and brain science and a senior author on the paper, have a longstanding interest in psychological theories of self-regulation, also called self-control or willpower.

"We seek to understand situations in which people face temptations and try to not act on them," says Kelley.

The researchers note that the first step toward controlling cravings may be an awareness of how much you are affected by specific triggers in the environment, such as the arrival of the dessert tray in a restaurant.

"You need to actively be thinking about the behavior you want to control in order to regulate it," remarks Kelley. "Self-regulation requires a lot of conscious effort."

Provided by Dartmouth College

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