New method of using nanotube x-rays creates CT images faster than traditional scanners

Aug 02, 2006

Scientists at the University of North Carolina at Chapel Hill have developed a new method to create computed tomography (CT) images using carbon nanotube x-rays that works much faster than traditional scanners and uses less peak power.

The work is another step toward developing scanners for medical imaging and homeland security that are smaller, faster, and less expensive to operate, said Dr. Otto Zhou, Lyle Jones Distinguished Professor of Materials Science, in the curriculum in applied and materials sciences and the department of physics and astronomy, both in UNC's College of Arts and Sciences.

"The current CT scanners take images sequentially, which is slow and inefficient. Using the nanotube x-ray technology, we show in this paper the feasibility of multiplexing - taking multiple images at the same time," Zhou said.

Carbon nanotubes, made of layers of carbon atoms, can be as small as one nanometer - one billionth of a meter - in diameter. The UNC team uses them in this work because they can emit electrons without high heat.

The new development is published in the current edition of the journal Applied Physics Letters. The lead author of the paper is Dr. Jian Zhang, a postdoctoral research associate in the UNC School of Medicine's department of radiation oncology. In addition to Zhou, other authors - all from UNC - are Dr. Sha Chang, associate professor of radiation oncology; doctoral candidate Guan Yang and Dr. Jianping Lu, professor of condensed matter physics, both of the department of physics and astronomy; and Dr. Yueh Lee, an intern at the medical school and an adjunct assistant professor in physics and astronomy.

Traditional CT scanners use a single x-ray source that takes approximately 1,000 images from multiple angles by mechanically rotating either the x-ray source or the object being scanned at high speed.

In 2005, Zhou and colleagues created a scanner with multiple x-ray sources, called a multipixel scanner. The machine required no mechanical motion but switched rapidly among many x-ray sources, each taking an image of the object from a different angle in fast succession.

The team's newest innovation combines this multiple-x-ray-source innovation with a principle called multiplexing, in which all the x-ray sources are turned on simultaneously to capture images from multiple views at the same time.

"Let's take a simple case where suppose you need 10 images," Zhou said. "Let's say each view take one second. In the conventional step-and-shoot method used for the current CT scanners, you take one shot, and the first pixel stays on for one second. Then we turn on the second pixel, and that stays on for one second." The whole process would take 10 seconds.

"With multiplexing, we can have all the x-ray pixels on at the same time for maybe 2 seconds. You still get all the images, only faster, and we need only about half of the original x-ray peak power," Zhou said.

Multiplexing is a known concept used by, for instance, cellular phones. Millions of cell phone signals travel along the same frequency band, then are separated into coherent messages at their destinations.

"What makes the multiplexing CT scanning possible is the novel multi-pixel x-ray source we developed and the ability to program each x-ray pixel electronically," Zhou said.

In this study, Zhou and colleagues took images of a computer circuit board using a prototype multiplexing scanner, then compared the images to those generated by a traditional x-ray scanner. The images showed little difference in resolution or clarity, but the prototype multiplexing scanner got the job done faster.

"For this paper we built a prototype or demonstration scanner that gives a limited number of views, to image a simple object," Zhou said. "Our next step is to develop a small CT scanner for small animal imaging."

Source: University of North Carolina at Chapel Hill

Explore further: The latest fashion: Graphene edges can be tailor-made

add to favorites email to friend print save as pdf

Related Stories

Obama recommends extended wilderness zone in Alaska

8 hours ago

US President Barack Obama said Sunday he would recommend a large swath of Alaska be designated as wilderness, the highest level of federal protection, in a move likely to anger oil proponents.

NASA craft set to beam home close-ups of Pluto

8 hours ago

Nine years after leaving Earth, the New Horizons spacecraft is at last drawing close to Pluto and on Sunday was expected to start shooting photographs of the dwarf planet.

Navy wants to increase use of sonar-emitting buoys

10 hours ago

The U.S. Navy is seeking permits to expand sonar and other training exercises off the Pacific Coast, a proposal raising concerns from animal advocates who say that more sonar-emitting buoys would harm whales and other creatures ...

Uganda seizes massive ivory and pangolin haul

10 hours ago

Ugandan wildlife officers have seized a huge haul of elephant ivory and pangolin scales, representing the deaths of hundreds of endangered animals, police said Sunday.

Recommended for you

The latest fashion: Graphene edges can be tailor-made

Jan 23, 2015

Theoretical physicists at Rice University are living on the edge as they study the astounding properties of graphene. In a new study, they figure out how researchers can fracture graphene nanoribbons to get ...

Nanotechnology changes behavior of materials

Jan 23, 2015

One of the reasons solar cells are not used more widely is cost—the materials used to make them most efficient are expensive. Engineers are exploring ways to print solar cells from inks, but the devices ...

Gold 'nano-drills'

Jan 22, 2015

Spherical gold particles are able to 'drill' a nano-diameter tunnel in ceramic material when heated. This is an easy and attractive way to equip chips with nanopores for DNA analysis, for example. Nanotechnologists ...

The importance of building small things

Jan 22, 2015

Strong materials, such as concrete, are usually heavy, and lightweight materials, such as rubber (for latex gloves) and paper, are usually weak and susceptible to tearing and damage. Julia R. Greer, professor ...

Graphene brings quantum effects to electronic circuits

Jan 22, 2015

Research by scientists attached to the EC's Graphene Flagship has revealed a superfluid phase in ultra-low temperature 2D materials, creating the potential for electronic devices which dissipate very little ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.