Posts Tagged ‘publishing’

New method for non-invasive prostate cancer screening

Now a team of researchers led by Shaoxin Li at Guangdong Medical College in China has demonstrated the potential of a new, non-invasive method to screen for prostate cancer, a common type of cancer in men worldwide. They describe their laboratory success testing an existing spectroscopy technique called surface-enhanced Raman scattering (SERS) with a new, sophisticated analysis technique called support vector machine (SVM).

As they described in a new paper in Applied Physics Letters, from AIP Publishing, they combined SERS and SVM and applied them to blood samples collected from 68 healthy volunteers and 93 people who were clinically confirmed to have prostate cancer. They found their technique could identify the cases of cancer with an accuracy of 98.1 percent.

If the technique proves safe and effective in clinical trials, it may become a new method available to patients and their doctors, helping to improve the early detection and diagnosis of this type of cancer, said Li.

“The results demonstrate that label-free serum SERS analysis combined with SVM diagnostic algorithm has great potential for non-invasive prostate cancer screening,” said Li. “Compared to traditional screening methods, this method has the advantages of being non-invasive, highly sensitive and very simple for prostate cancer screening.”

A COMMON CAUSE OF CANCER

According to the World Health Organization, prostate cancer is one of the most common types of cancer in men worldwide and a leading cause of cancer-related death. Every year, there are about 899,000 new cases and 260,000 mortalities, comprising 6 percent of all cancer deaths globally. About 1 in every 6 men will develop prostate cancer over their lifetimes.

While a simple blood test for elevated levels of a protein marker known as prostate specific antigen (PSA) has been used for years to screen for early cases of prostate cancer, the test is far from perfect because the elevated PSA levels can be caused by many things unrelated to cancer. This contributes to over-diagnosis, uncomfortable tissue biopsies and other unnecessary treatment, which can be costly and carry significant side effects. Because of this, the U.S. Preventative Services Task Force now recommends against PSA-based screening for prostate cancer.

According to Li, many scientists have thought about applying SERS to cancer detection because the surface-sensitive type of spectroscopy has been around for years and is sensitive enough to identify key molecules in very low abundance, like pesticide residues on a contaminated surface. This would seem to make it perfect for spotting subtle signals of DNA, proteins or fatty molecules that would mark a case of cancer — exactly why he and his team tackled the problem.

The challenge, he said, was that these changes were, if anything, too subtle. The signal differences between the serum samples taken from the 68 healthy volunteers and the 93 people with prostate cancer were too tiny to detect. So to accurately distinguish between these samples, Li’s group employed a powerful spectral data processing algorithm, support vector machine (SVM), which effectively showed the difference.

While the work is preliminary, it shows that serum SERS spectroscopy combined with SVM diagnostic algorithm has the potential to be a new method for non-invasive prostate cancer screening, Li said. The next research step, he added, is to refine the method and explore whether this method can distinguish cancer staging.

source : http://www.sciencedaily.com/releases/2014/09/140902114041.htm

3-in-1 optical skin cancer probe

Researchers from the University of Texas at Austin’s Cockrell School of Engineering have now developed a probe that combines into one device three unique ways of using light to measure the properties of skin tissue and detect cancer. The researchers have begun testing their 3-in-1 device in pilot clinical trials and are partnering with funding agencies and start-up companies to help bring the device to dermatologists’ offices.

The researchers describe the skin cancer probe in a new paper published in the journal Review of Scientific Instruments, from AIP Publishing.

Skin cancers of all types are the most common forms of cancer in North America, and melanoma, the most deadly form of skin cancer, is one of the leading causes of cancer death, killing nearly 10,000 people every year in the United States.

Currently, the only definitive way to diagnose skin cancer is to perform a biopsy, in which doctors remove a suspect skin lesion and then examine the stained tissue under a microscope to look for cancerous cells. Determining which lesions to biopsy is an imprecise art, however, and for every case of skin cancer detected there are roughly 25 negative biopsies performed, translating to a cost of $6 billion to the U.S. health care system, according to estimations performed by the researchers.

James Tunnell, an associate professor in the biomedical engineering department at UT, believes the new probe developed by his team could eventually help reduce the high number and cost of negative biopsies by giving a clear picture of which skin lesions are most likely cancerous. He and his colleagues combined three common spectroscopic techniques — Raman spectroscopy, diffuse reflectance spectroscopy, and laser-induced fluorescence spectroscopy — into one probe to create a more complete picture of a skin lesion. By revealing information invisible to the human eye, the probe could offer a better screening tool for cancer and eliminate many negative biopsies.

As normal skin becomes cancerous, cell nuclei enlarge, the top layers of skin can thicken and the skin cells can increase their consumption of oxygen and become disorganized, Tunnell said. The changes alter the way light interacts with the tissue.

To detect all these changes requires multiple spectroscopic techniques. For example, diffuse optical spectroscopy is sensitive to absorption by proteins such as hemoglobin while Raman spectroscopy is sensitive to vibrational modes of chemical bonds, such as those found in connective tissues, lipids, and cell nuclei, Tunnell noted.

Previous research efforts have tried combining spectroscopic techniques to aid in skin cancer detection, but the University of Texas team is the first to combine three techniques in a single probe that would be inexpensive enough to be used widely in clinics and doctors’ offices. The probe itself is about the size of a pen and the spectroscopic and computer equipment that supports it fits neatly onto a portable utility cart that can be wheeled between rooms. Each reading takes about 4.5 seconds to perform. The 3-in-1 nature of the probe saves time and money while still giving a comprehensive examination of the skin properties.

“Skin is a natural organ to apply imaging and spectroscopy devices to because of its easy access,” Tunnell said. Most devices have been at the research stage for the last 10 years or so, but several are now undergoing clinical development, he noted. “This probe that is able to combine all three spectral modalities is the next critical step to translating spectroscopic technology to the clinic.”

source : http://www.sciencedaily.com/releases/2014/08/140805131714.htm