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ThermoDox October 17, 2008

Posted by tomography in Cancer, development, Innovation.
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I am certain that one day there will be a cure for cancer, that is why I try to keep up to date with whatever advances there are in cancer treatment. I stumbled upon ThermoDox, an interesting technology that utilizes heat-activated liposomes to kill cancerous cells.

Liposomes are made of that same materials as cells, phospholipids, thus they form a hollow structure that is soluble in water but may fuse with cell membranes. Since they are hollow, they may be filled with anti-cancer drugs.

ThermoDox liposomes are filled with Doxorubicin, a popular anti-cancer agent. They circulate within the bloodstream, so they reach all parts of the body, but only when focused heat is applied do they release their deadly load onto cancerous cells. Thus side-effects are reduced, and more efficient cancer treatment is achieved.

ThermoDox is now in phase III, and you may read more on this technology here.

– Andras

Meet Toshiba’s new scanner: Aquilion One June 21, 2008

Posted by tomography in CT, development, Innovation, Radiology.
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It is official! Toshiba’s new Aquilion One scanner is out! After 10 years and 500 millions dollars of development, new 320-slice scanners are going online in select hospitals in three major U.S. cities: Baltimore, Boston and Las Vegas. Toshiba gets the last laugh having been previously outpaced by one of its major competitors, Philips Medical Systems. The technological details are impressive:

  • It uses 320 ultra-high-resolution x-ray detectors, each half a millimeter wide
  • The detector rotates every 350 msec
  • Single pass of the brain provides the volumetric data to produce CT angiogram, venogram, digital subtraction angiogram, and whole-brain perfusion images
  • A whole heart can be captured in a single rotation
  • All this with even less radiation burden on the patient

According to the official website your hospital may save considerable amounts of money, if this machine is used in events such as acute chest pain and stroke. For example, in practice this is how it would work out. Let’s suppose a patient comes in with acute chest pain. You examine him, take an ECG reading, order a CT scan, or a nuclear stress scan, and then finally send him to intervention cardiology, where he receives his proper treatment (a stent for example). It is estimated that all this would cost around twice as much (and much more time) as having him lay down in an Aquilion One, and then send him to intervention. I see their point, but I think that this does not hold for all cases as implied by the company website. The emphasis should be on proper events!

By the end of the day it is about people’s lives and correct diagnosis, so I am happy that new advances in technology are helping us achieve those goals easier. If anybody has any images taken with such a high resolution scanner (does not necessarily have to be with this particular type), please email it to us!

Further reading:

– Andras

Xray goes digital February 26, 2008

Posted by tomography in CT, development, Off Topic, Radiology, What tomorrow brings?, X-ray.
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After a long break I returned to one of my beloved hobbies, photography. I was very happy when my brand new DSLR (digital single-lens reflex) camera arrived. Coming back wasn’t that easy, though I had years of practice with SLR and lately used more digital compacts too. The development, we went through is remarkable, let it be hardware, software, quality, ease of use or techniques. One dealing with digital photography really has to know more than the basis and should be up to date, to create the best pictures. So I ran over some wikis…

One really fundamental thing is the image sensor, as there is no film. Sensors works as film. This is a digital light sensitive flan – a photoelectric sensor, which perceives the quantity of light coming through the lens, and then forwards this essential information as pixels to the processor. So it’s obvious why companies emphasize developing better and better sensors.

cmosMaybe you heard of these, like CCD (charge-coupled device) or CMOS (complementary metal-oxide-semiconductor). CCD is an analog shift register, enabling analog signals (electric charges) to be transported through successive stages (capacitors) controlled by a clock signal.

Basicaly there are two groups of image sensors (IS). CCD-CMOS and CCD-NMOS (n-channel metal-oxide-semiconductor). In weekdays we call them -not so accurately- CCD and CMOS. Each has unique strengths and weaknesses giving advantages in different applications. Neither is categorically superior to the other, although vendors selling only one technology have usually claimed otherwise. The difference between these two is in the manufacturing process. Both types of imagers convert light into electric charge and process it into electronic signals. In a CCD sensor, every pixel’s charge is transferred through a very limited number of output nodes (often just one) to be converted to voltage, buffered, and sent off-chip as an analog signal. All of the pixel can be devoted to light capture, and the output’s uniformity (a key factor in image quality) is high. In a CMOS sensor, each pixel has its own charge-to-voltage conversion, and the sensor often also includes amplifiers, noise-correction, and digitization circuits, so that the chip outputs digital bits. With each pixel doing its own conversion, uniformity is lower. But the chip can be built to require less off-chip circuitry for basic operation. Both CCD and CMOS imagers can offer excellent imaging performance when designed properly. CCD and CMOS will remain complementary. The choice continues to depend on the application and the vendor more than the technology.

The reason I wrote about ISs was the creation of The University of Sheffield, namely large and sensitive CMOS sensors for the next generation of X-ray based imaging systems.

Easier to use and faster than the imagers used in current body scanners, and with very large active pixel sensors with an imaging area of approximately 6cm square, the technology has been specifically developed to meet demanding clinical applications such as x-ray imaging and mammography. This silicon imager is about 15 times larger in area than the latest Intel processors. The next step of the project is to produce wafer-scale imagers which can produce images that approach the width of the human torso. This will eliminate the need for expensive and inefficient lenses and so enable lower-cost, more sensitive and faster medical imaging systems.

These sensors were developed by the CMOS Sensor Design Group at STFC´s Rutherford Appleton Laboratory in association with the University of Sheffield and University College London.

Dark-field X February 22, 2008

Posted by tomography in development, Radiology.
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Having a look back at the gadgets, I met our good old friend again… X-ray. Further more, it was called dark-field.

Unlike traditional X-ray techniques that produce radiographies by shining the object with X-rays in order to collect the unabsorbed light, dark-field imaging captures the light scattered throughout the material, totally ignoring the remnant radiation. This leads to stunning overall clarity. Dark-field images provide more detail than ordinary x-ray radiographies and could be used to diagnose the onset of osteoporosis, Alzheimer’s disease or breast cancer. As cancer or plaque cells scatter radiation slightly differently than normal cells, dark-field x-ray images can also be used to explore soft tissue, providing safer early diagnosis of breast cancer or Alzheimer’s disease.darkfieldchocolate

Dark-field scan of a chocolate (pic from Gizmag). I liked it better than fish or chicken wing, which you can download here.

These imaging techniques are expensive and the tools used are also not consumer. Take Paul Scherrer Institute’s (PSI) dark-field X-ray, assisted by a 300m in diameter synchrotron and sophisticated optics, not less than $200 million.

PSI and the Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland have developed a novel method for producing dark-field X-ray images at wavelengths used in typical medical and industrial imaging equipment. With the new nanostructured gratings that permit the use of a broad energy spectrum, including the standard range of energies, dark-field images could soon be produced using ordinary X-ray equipment already in place in hospitals.

Colour X-ray December 8, 2007

Posted by tomography in development, Off Topic, Radiology, Tomography, X-ray.
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Scientists at The University of Manchester have developed a new x-ray imaging technique. This new method aims to create colour x-ray pictures 3D. The new technique developed by the Manchester team is called tomographic energy dispersive diffraction imaging (TEDDI). It requires a synchrotron radiation white X-ray source so it is capable of producing structure composition profiles with resolutions approaching 1 micron. Such a facility would be ideal for studying a whole range of problems in materials and engineering science.

spacexray

Current imaging systems such as spiral CAT scanners do not use all the information contained in the X-ray beam. We use all the wavelengths present to give a colour X-ray image. This extra information can be used to fingerprint the material present at each point in a 3D image. – says Professor Cernik

Nice expectations on biomaterials. Distinguishing normal tissue from abnormal.

We have demonstrated a new prototype X-ray imaging system that has exciting possibilities across a wide range of disciplines including medicine, security scanning and aerospace engineering.

Yet the problem is time. To create a scan takes hours, but scientists believe that it will be reduced to just a few minutes. The method could be useful in specific tissue identification in humans or even identifying heroin, cocaine in freight; or could be useful at car and aerospace engineering showing whether welds are damaged or have too much strain. So reaching the medical line is not that close, but what is late does not go by.

Think small December 1, 2007

Posted by tomography in development, Off Topic, Tomography.
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A remarkably simple experiment devised by scientists yields important information about the mechanical properties of thin films (nanoscopically thin layers of material that are deposited onto a metal, ceramic or semiconductor base)

starburstThe findings impact a broad range of scientific disciplines and applications, from cosmetics to coatings, to micro- and nanoelectronics, filters, very low loss high density optical films etc. Understanding the mechanical properties of thin films is essential to their performance and optimization.

Until now, determining the mechanical properties of these thin films was either an expensive and time-consuming endeavor, requiring powerful microscopes to view the films, or scientists examined composite structures and made uncertain assumptions. This new research will give scientists a simple way to access the material properties of most thin films. Low-power optical microscope is used to observe what happens when they place a tiny drop of water on thin film as it floats in a Petri dish of water. The capillary tension of the drop of water produces a starburst of wrinkles in the film. The number and length of the wrinkles are determined by the elasticity and thickness of the film.

In some of the materials studied, the wrinkles in the ultrathin polymer films vanished with time. This vanishing provides insight into the relaxation process of an ultrathin film by yielding information on the way polymer chains move in the highly confined geometry.

Source: NSF

Greater contrast in detection November 28, 2007

Posted by tomography in development, Innovation, Off Topic, Radiology.
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nvidia

NVIDIA Corporation, the worldwide leader of programmable graphics processor technologies, and Planar Systems, makers of specialty displays, are cooperating closely to produce display systems that will enable doctors to more effectively screen for breast cancer. The two companies are working to develop high-contrast, 10-bit grayscale display systems for use in mammography and other medical applications.

Currently, digital mammography displays that rely on standard PC workstations are limited to 8-bit grayscale, which provides only 256 possible shades of gray for each pixel. Being limited to 256 shades-of-gray can sometimes obscure valuable data when an image is displayed; mammography systems and other medical sensors, however, are capable of greater degrees of contrast.

Instead of developing specialty hardware, NVIDIA and Planar have developed a method of “pixel packing” that allows 10-bit or 12-bit grayscale data to be transmitted from an NVIDIA Quadro® graphics board to a Planar Dome display using a standard DVI cable. Instead of three 8-bit grayscale channels, now two 10- or 12-bit channels are transmitted, providing up to 864 possible shades of gray at more than three times the image contrast of an 8-bit system.

The best part of this display solution is that specialty hardware is not required, making it readily available for use with other radiology functions. Instead of developing a specialty graphics board that supports 10- or 12-bit grayscale, NVIDIA has incorporated the pixel packing functionality into its Quadro™ driver, allowing Quadro FX 4600 graphics or higher to support a wide range of grayscale panels from various manufacturers.

Soon, without a lot of increased costs, radiologists will be able to use these 10-bit display systems to screen for breast cancer more efficiently and with greater confidence!

Source: NVIDIA

MRI helps surgical planing November 18, 2007

Posted by tomography in development, MRI, Surgery.
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The preoperative magnetic resonance imaging (MRI) image is no longer accurate enough for brain surgery.

brainsurgeryMRI

Everything changes after the surgeons open your skull. Your brain, and the tumor inside it, no longer fully float in their protective bath of cerebrospinal fluid. Gravity comes into play, as does the atmospheric pressure of the operating theater. The brain responds to these foreign forces, the cerebral tissue sagging, rebounding and changing shape. The tumor that the neurosurgeons want to remove also has changed position.

Thus, the brain the surgeon operates on is a different shape from the one depicted in the preoperative MRI. Of course, once the surgeon begins work, the shape of the brain changes even more. The brain’s changing shape is a problem not only of space, but of time.

In essence, the William and Mary team provides the surgical team with a dynamic computer model of the patient’s brain. In clinical trials, Chrisochoides (mathematician professor at the College of William and Mary) says his team can render a new model in six or seven minutes, but hopes to be able to do so in under two minutes.

We want to help the neurosurgeon make an informed decision of what to cut, where the critical paths are, what areas to avoid, he said. I’m neither a neurosurgeon nor a doctor, so the contribution of my research is to make this distillation of objects really, really, really fast.

The process begins with the acquisition of a variety of images before the surgery – images which are otherwise unavailable in the middle of the procedure. Low-resolution intraoperative data allows the tracking of the shift of brain matter and calculates how to change the preoperative images accordingly.

The brain, of course, is an elastic object.

If you push it, -Chrisochoides said-, it takes energy and then after a while it settles down. We can calculate the place where it settles by solving the partial differential equation. Mathematicians can tell us that there is a solution, but they cannot tell us what the solution is. There’s no such thing for this equation. There’s no analytic solution. So we have to approximate.

Chrisochoides approximates the geometry of the patient’s brain by tessellating it into triangles in three dimensions, or in other words, generating a mesh representing the brain. Users wear 3D glasses to examine projected images of a brain. The glasses give the audience a striking 3D effect, showing off the curves of the vector arrows indicating how displacement was acting on the brain.

Source: NSF