New technique uses 25 times less radiation to produce tumor images in high-resolution 3D

Wednesday, April 09, 2014 by: David Gutierrez, staff writer
Tags: breast cancer, tumor images, radiation

(NaturalNews) Although medical applications may still be several years away, researchers have developed a new cancer screening technique that uses 25 times less radiation than a current mammogram but produces a dramatically better image.

"This new technique can open up the doors to the clinical use of computed tomography [CT] in the breast diagnosis, which would be a powerful tool to fight even better and earlier against breast cancer," said Maximilian Reiser of the Ludwig Maximilians University in Munich (LMU), one of the researchers who helped develop the technique.

Early detection is linked to significantly improved breast cancer outcomes. Currently, the standard breast cancer screening method is "dual-view digital mammography," which uses radiation to take two separate images of the breast. Because these mammograms render a three-dimensional organ in only two dimensions, they typically fail to detect 10 to 20 percent of tumors. In addition, 2D mammograms often render false positives, as normal tissue can take on a strange appearance when flattened into two dimensions.

Although 3D CT scans produce much-higher-resolution images than 2D mammograms, they typically require much more radiation to do so. This prevents their use in routine cancer screening -- particularly for highly radiation-sensitive organs such as the breast.

Advanced techniques use less radiation

The new, lower radiation CT scan was tested in a study published in the Proceedings of the National Academy of Sciences in October 2012. The technique was developed by physicists, radiologists and mathematicians from LMU, the European Synchrotron Radiation Facility, and the University of California-Los Angeles.

The researchers achieved such a dramatically lower radiation dose by changing three separate factors of normal CT scans. The first change involved replacing standard X-rays with high-energy X-rays which are more likely to pass through tissue and thereby expose the body to six times less radiation. The second change involved a technique called "phase contrast imaging," which requires fewer X-rays to produce the same image. The third change involved reducing the number of X-rays even further and then applying a mathematical algorithm called "equally sloped tomography" (EST) to reconstruct a higher-resolution image.

In the 2012 study, the researchers successfully used the EST algorithm to produce a high-resolution, 3D image of the breast using 25 times less radiation than a mammogram. They then took images of the same breast using several other standard 3D imaging techniques. In a blind test, five independent LMU radiologists all ranked the images produced from the new technique as having the best contrast, sharpness and image quality.

"Three-dimensional reconstructions, like the ones created in this research, are produced using sophisticated software and a powerful computer that can combine many images into one 3-D image, much like the slices of an orange," UCLA researcher Jianwei (John) Miao said. "By rethinking the mathematic equations of the software in use today, we developed a more powerful algorithm that requires fewer slices to get a clearer 3-D picture."

Applications still far off

"After dramatically reducing the dose delivered during the examination of the breast, our next objective is to develop this technique in the early visualisation of other human diseases and to work towards its clinical implementation," said researcher Paola Coan.

Unfortunately, it may be some time before the new technique is ready for regular use. One of the major hurdles is the need to produce an X-ray source small enough to be practical at hospitals.

"Many research groups are actively working to develop this device and once this hurdle is cleared, the new X-ray technique is poised to make a big impact on society," researcher Emmanuel Brun said.

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