Compact light source improves CT scans

The Compact Light Source by Palo Alto-based Lyncean Technologies Inc. generates X-rays suitable for advanced tomography. The car-sized device is a miniature version of football-field-sized X-ray generators known as synchrotrons and it emerged from basic research at SLAC in the late 1990s and early 2000s.
Credit: Lyncean Technologies Inc.

A new study shows that the recently developed Compact Light Source (CLS) — a commercial X-ray source with roots in research and development efforts at the Department of Energy’s SLAC National Accelerator Laboratory — enables computer tomography scans that reveal more detail than routine scans performed at hospitals today. The new technology could soon be used in preclinical studies and help researchers better understand cancer and other diseases.

With its ability to image cross sections of the human body, X-ray computer tomography (CT) has become an important diagnostic tool in medicine. Conventional CT scans are very detailed when it comes to bones and other dense body parts that strongly absorb X-rays. However, the technique struggles with the visualization and distinction of “soft tissues” such as organs, which are more transparent to X-rays.

“Our work demonstrates that we can achieve better results with the Compact Light Source,” says Professor for Biomedical Physics Franz Pfeiffer of the Technical University of Munich in Germany, who led the new study published April 20 in the Proceedings of the National Academy of Sciences. “The CLS allows us to do multimodal tomography scans — a more advanced approach to X-ray imaging.”

More than One Kind of Contrast

The amount of detail in a CT scan depends on the difference in brightness, or contrast, which makes one type of tissue distinguishable from another. The absorption of X-rays — the basis for standard CT — is only one way to create contrast.

Alternatively, contrast can be generated from differences in how tissues change the direction of incoming X-rays, either through bending or scattering X-ray light. These techniques are known as phase-contrast and dark-field CT, respectively.

“Organs and other soft tissues don’t have a large absorption contrast, but they become visible in phase-contrast tomography,” says the study’s lead author, Elena Eggl, a researcher at the Technical University of Munich. “The dark-field method, on the other hand, is particularly sensitive to structures like vertebrae and the lung’s alveoli.”

Shrinking the Synchrotron

However, these methods require X-ray light with a well-defined wavelength aligned in a particular way — properties that conventional CT scanners in hospitals do not deliver sufficiently.

For high-quality phase-contrast and dark-field imaging, researchers can use synchrotrons — dedicated facilities where electrons run laps in football-stadium-sized storage rings to produce the desired radiation — but these are large and expensive machines that cannot simply be implemented at every research institute and clinic.

Conversely, the CLS is a miniature version of a synchrotron that produces suitable X-rays by colliding laser light with electrons circulating in a desk-sized storage ring. Due to its small footprint and lower cost, it could be operated in almost any location.

“The Large Hadron Collider at CERN is the world’s largest colliding beam storage ring, and the CLS is the smallest,” says SLAC scientist Ronald Ruth, one of the study’s co-authors. Ruth is also chairman of the board of directors and co-founder of Palo Alto-based Lyncean Technologies Inc., which developed the X-ray source based on earlier fundamental research at SLAC. “It turns out that the properties of the CLS are perfect for applications like tomography.”

More Modes, Finer Detail

In the recent study, the researchers reported the first “multimodal” CT scan with the CLS: They recorded all three imaging modes — absorption, phase contrast and dark field — at the same time. Using a total of 361 two-dimensional X-ray images of an infant mouse taken from different directions, the scientists generated cross-section images of the animal.

“The absorption images only show bones and air-filled organs,” Eggl says. “However, the phase-contrast and dark-field images reveal much more detail, showing different organs such as the heart and liver. We can even distinguish different types of fat tissue, which is not possible with absorption-based CT scans.”

Using a standard sample of chemically well-defined liquids, the scientists also demonstrated that they could not only visualize but also quantify differences in their properties — information that can be applied to various body tissues and that is only obtained when combining all three tomography modes.

Implications for Cancer, Materials

The success of this research, which was done on a CLS prototype, has led to the commissioning of the first commercial device.

The researchers’ next goal is to use the CLS for phase-contrast and dark-field CT in preclinical studies — an approach that could help visualize cancer. “We work closely together with two clinics to study tumors,” Eggl says. “One of our plans is to image breast tissue samples and also entire breasts after mastectomy to better understand the clinical picture of breast cancer.”

Besides medical applications, multimodal tomography could also open up new possibilities in materials science, for instance, in studies of extremely durable and light-weight carbon fibers and other fibrous materials, where the X-ray absorption contrast provides little information.

Please follow this link to Science Daily for the original story.

For vast majority of seniors who own one, a smartphone equals ‘freedom’

When it comes to tech adoption, seniors generally lag behind their younger counterparts. But for Americans ages 65 and older who own a smartphone, having one in their pocket is a liberating experience.

Asked if they feel that their phone represents “freedom” or “a leash,” 82% of smartphone-owning seniors described their phone as freeing, compared with 64% of those ages 18 to 29. By contrast, 36% of adult smartphone owners under the age of 30 described their phone as a leash, double the 18% of adults ages 65 and older who chose this term to describe their phone.

Similarly, when asked to describe their smartphone as “connecting” or “distracting,” older users are significantly more likely to choose “connecting” as the best descriptor. On the other hand, younger smartphone users are twice as likely as older adults to view their phone as “distracting” (37% vs. 18%).

Our survey did not directly ask why users chose the terms that they did, but differences in usage patterns may play a role. Younger adults tend to use their phones for a far wider range of purposes (especially social networking and multimedia content) and are much more likely to turn to their phone as a way to relieve boredom and to avoid others around them.

Older adults, by contrast, tend to use their phones for a narrower range of purposes – especially basic communication functions such as voice calling, texting and email. For young adults, smartphones are often the device through which they filter both the successes and annoyances of daily life – which could help explain why these users are more likely to report feeling emotions about their phone ranging from happy and grateful to frustrated or angry during a weeklong survey.

It is true, overall, that older Americans are less likely to be online, have broadband at home or own a mobile device. The same applies to smartphones: Only a quarter (27%) of adults ages 65 and older own them, compared with 85% of 18- to 29-year-olds, according to a Pew Research Center report released earlier this month.

A previous Pew Research study found that lower adoption rates of new technologies are often related to barriers seniors face when adopting them. These include medical conditions that make it difficult for older Americans to use certain technologies or devices. Skepticism about the benefits of technology and lack of digital literacy are other deterrents cited by older adults.

But that’s not to say older Americans aren’t broadening their digital experiences. In 2014, for the first time, more than half of online seniors indicated that they use Facebook: 56% of online adults ages 65 and older do so, up from 45% a year earlier. Internet use and broadband adoption continue to climb among older adults, and although there remains a wide age gap in smartphone ownership, the proportion of older adults who own a smartphone has increased by 8 percentage points since early 2014. Plus, older Americans who are internet adopters tend to have highly positive attitudes about the impact of online access on their lives, including the access that smartphones give them.

For more information and the original story follow this link to Pew Research Center.