New X-ray technique could improve bomb detection and breast cancer treatment

Funded by the Engineering and Physical Sciences Research Council (EPSRC), a major five-year project led by UCL (University College London) has achieved this breakthrough. The work also involved dozens of industrial, academic and research partners in the UK and worldwide.

Compared with conventional X-rays, the technology can, for example, identify tumours in living tissue earlier and spot smaller cracks and defects in materials. This is because it excels at determining different shapes and different types of matter — a capability that conventional X-rays could only match by using prohibitively high doses of radiation.

The technique at the heart of the advance is called phase-contrast X-ray imaging. Instead of measuring the extent to which tissue or materials absorb radiation — as in conventional X-ray imaging — it measures the physical effect that passing through different types of tissue or material has on the speed of the X-ray itself.

Professor Alessandro Olivo, who led the project team, says: “The technique has been around for decades but it’s been limited to large-scale synchrotron facilities such as Oxfordshire’s Diamond Light Source. We’ve now advanced this embryonic technology to make it viable for day-to-day use in medicine, security applications, industrial production lines, materials science, non-destructive testing, the archaeology and heritage sector, and a whole range of other fields.”

This vast potential is already beginning to be explored. For example:

· Under licence, Nikon Metrology UK has incorporated the technology into a prototype security scanner. This is currently being tested and further developed to provide enhanced threat detection against weapons and explosives concealed, for example, in baggage.

· Building on the EPSRC-funded work, a new three-year project supported by the Wellcome Trust will see the Nikon Metrology/UCL team develop a prototype scanner for use during breast cancer surgery in collaboration with Barts Heath and Queen Mary University of London. The aim is to help surgeons determine the exact extent of the malignancy and to reduce the need to recall patients for further operations, resulting in more effective breast conservation surgery, less need for full mastectomies and more rapid treatment.

· The technology can even detect some tissue types invisible to conventional X-ray machines, such as cartilage, and plans are proceeding to set up a spinout company to take this aspect towards commercialisation.

Professor Olivo says: “This has the potential to be incredibly versatile, game-changing technology. We’re currently negotiating with a number of companies to explore how it could be put to practical use. There’s really no limit to the benefits this technique could deliver.”

New PET scan for prostate cancer patients

The scan can detect the location and extent of cancer that has recurred after initial treatment and spread to other parts of the body. Prostate PET/CT scans can detect cancer earlier than either CT scans alone or MRI scans.

“By knowing where the cancer has gone, we can provide more accurate, precise and selective treatment,” said Loyola nuclear physician Bital Savir-Baruch, MD.

After the initial diagnosis of prostate cancer, patients undergo treatment such as surgery, cryotherapy or radiation. In some cases the cancer may recur. Following treatment, men are monitored with periodic PSA blood tests. An increase in PSA levels indicates the cancer probably has recurred, but the location is often difficult to determine.

PET stands for positron emission tomography. It’s usually combined at the same time with CT (computerized tomography) to improve the quality of the images and help localize abnormalities. PET employs a slightly radioactive tracer drug that homes in on the targeted tissue. PET/CT scans work well for breast, lung, colon and other cancers, but until recently did not work well for prostate cancer because there were no effective tracer drugs for the disease. That changed on May 27, when the U.S. Food and Drug Administration approved a new PET scan tracer drug specifically for prostate cancer.

The drug is a synthetic amino acid analog called Axumin™ (fluciclovine F-18). Attached to the amino acid is a radioactive tracer, fluorine-18. After Axumin is injected into the patient, the drug is taken up by prostate cancer cells. The fluorine-18 emits a small amount of energy in the form of gamma rays. The PET/CT scanner detects this energy, and a computer produces a detailed image.

Dr. Savir is among the first nuclear physicians in the country trained to read prostate cancer PET/CT scans employing the Axumin tracer drug. While doing research training and completing a nuclear medicine residency at Emory University, Dr. Savir was part of the research team that developed and conducted clinical trials that led to the FDA approval of Axumin.

Loyola is offering PET/CT scans to previously treated prostate cancer patients who have increasing PSA levels indicating their cancer may have recurred. Patients are scanned from their thighs to their eyes. Loyola’s first patient was scanned with Axumin on Aug. 18.

“We are delighted that we can now offer PET/CT scans to prostate cancer patients in order to improve the quality of their care,” said Robert Wagner, MD, medical director of nuclear medicine. Dr. Wagner is a professor and Dr. Savir is an assistant professor in the Department of Radiology of Loyola University Chicago Stritch School of Medicine.

Enhancing molecular imaging with light

Now a Northwestern Engineering team has improved this groundbreaking technology by making it faster, simpler, less expensive, and increasing its resolution by four fold.

“Despite the success of electron microscopy and scanning probe microscope techniques, there has remained a need for an optical imaging method that can uncover not only nanoscopic structures but also the physical and chemical phenomena occurring on the nanoscale level,” said said Hao Zhang, associate professor of biomedical engineering in Northwestern’s McCormick School of Engineering. “We envision that our technique can accomplish this.”

Led by Zhang, the Northwestern team developed a new super-resolution optical imaging platform based on spectroscopy, a type of imaging that examines how matter responds to light. Called spectroscopic photon localization microscopy (SPLM), the platform can analyze individual molecules with sub-nanometer resolution.

The novel technology platform leverages photon localization microscopy (PLM), which captures inherent spectroscopic signatures of emitted photons, or light particles, to identify specific molecules. Current spectroscopic imaging and PLM technologies require multiple fluorescent dyes to enhance contrast in the resulting microscopic images. Unable to distinguish between dyes, these techniques record multiple images from different discrete wavelength bands.

The Northwestern team’s SPLM, however, can characterize multiple dye molecules simultaneously, increasing the imaging speed in multi-stained samples. Removing the need for recording multiple images makes the imaging process simpler and less expensive. SPLM is also sensitive enough to distinguish minor differences from the same type of molecules.

“People need a series of filters and cameras to separate photons with different colors and acquire information,” Zhang said. “It can be rather complicated and expensive if multiple cameras are employed. Using our technology, we can acquire multi-color images without filters because we know which color is associated with which photons simultaneously.”

Supported by a Northwestern Engineering research catalyst award, the research was described online on July 25 in Nature Communications. Vadim Backman, the Walter Dill Scott Professor of Biomedical Engineering, and Cheng Sun, associate professor of mechanical engineering, served as co-authors of the paper. Biqin Dong, a postdoctoral fellow in Zhang’s laboratory, and Luay Almassalha, a graduate student in Backman’s laboratory, are co-first authors of the study.

While Zhang plans to apply this new technology to his own research in optical imaging, he believes it will be useful for many fields, from materials science to the life sciences.

“Our approach not only enhances existing super-resolution imaging by capturing molecule-specific spectroscopic signatures,” he said, “it will potentially provide a universal platform for unravelling nanoscale environments in complex systems at the single-molecule level.”

Making batteries from waste glass bottles

Titled “Silicon Derived from Glass Bottles as Anode Materials for Lithium Ion Full Cell Batteries,” an article describing the research was published in the Nature journal Scientific Reports. Cengiz Ozkan, professor of mechanical engineering, and Mihri Ozkan, professor of electrical engineering, led the project.

Even with today’s recycling programs, billions of glass bottles end up in landfills every year, prompting the researchers to ask whether silicon dioxide in waste beverage bottles could provide high purity silicon nanoparticles for lithium-ion batteries.

Silicon anodes can store up to 10 times more energy than conventional graphite anodes, but expansion and shrinkage during charge and discharge make them unstable. Downsizing silicon to the nanoscale has been shown to reduce this problem, and by combining an abundant and relatively pure form of silicon dioxide and a low-cost chemical reaction, the researchers created lithium-ion half-cell batteries that store almost four times more energy than conventional graphite anodes.

To create the anodes, the team used a three-step process that involved crushing and grinding the glass bottles into a fine white power, a magnesiothermic reduction to transform the silicon dioxide into nanostructured silicon, and coating the silicon nanoparticles with carbon to improve their stability and energy storage properties.

As expected, coin cell batteries made using the glass bottle-based silicon anodes greatly outperformed traditional batteries in laboratory tests. Carbon-coated glass derived-silicon (gSi@C) electrodes demonstrated excellent electrochemical performance with a capacity of ~1420 mAh/g at C/2 rate after 400 cycles.

Changling Li, a graduate student in materials science and engineering and lead author on the paper, said one glass bottle provides enough nanosilicon for hundreds of coin cell batteries or three-five pouch cell batteries.

“We started with a waste product that was headed for the landfill and created batteries that stored more energy, charged faster, and were more stable than commercial coin cell batteries. Hence, we have very promising candidates for next-generation lithium-ion batteries,” Li said.

This research is the latest in a series of projects led by Mihri and Cengiz Ozkan to create lithium-ion battery anodes from environmentally friendly materials. Previous research has focused on developing and testing anodes from portabella mushrooms, sand, and diatomaceous (fossil-rich) earth.

New nanoscale technologies could revolutionize microscopes, study of disease

“Usually, scientists have to use very expensive microscopes to image at the sub-microscopic level,” said Gangopadhyay, the C.W. LaPierre Endowed Chair of electrical and computer engineering in the MU College of Engineering. “The techniques we’ve established help to produce enhanced imaging results with ordinary microscopes. The relatively low production cost for the platform also means it could be used to detect a wide variety of diseases, particularly in developing countries.”

The team’s custom platform uses an interaction between light and the surface of the metal grating to generate surface plasmon resonance (SPR), a rapidly developing imaging technique that enables super-resolution imaging down to 65 nanometers–a resolution normally reserved for electron microscopes. Using HD-DVD and Blu-Ray discs as starting templates, a repeating grating pattern is transferred onto the microscope slides where the specimen will be placed. Since the patterns originate a widely used technology, the manufacturing process remains relatively inexpensive.

“In previous studies, we’ve used plasmonic gratings to detect cortisol and even tuberculosis,” Gangopadhyay said. “Additionally, the relatively low production cost for the platform also means it could be used to further detect a wide variety of diseases, particularly in developing countries. Eventually, we might even be able to use smartphones to detect disease in the field.”

Gangopadhyay’s work also highlights the collaborations that are possible at the Mizzou. Working with the MU Departments of Bioengineering and Biochemistry, the team is helping to develop the next generation of undergraduate and graduate students. Patents and licenses developed by MU technologies help create and enhance relationships with industry, stimulate economic development, and impact the lives of state, national and international citizens.

“Plasmonic gratings with nano-protrusions made by glancing angle deposition (GLAD) for single-molecule super-resolution imaging” recently was published in Nanoscale, a journal of the Royal Society of Chemistry.

Shedding light on the absorption of light by titanium dioxide

Anatase TiO2 is involved in a wide range of applications, ranging from photovoltaics and photocatalysis to self-cleaning glasses, and water and air purification. All of these are based on the absorption of light and its subsequent conversion into electrical charges. Given its widespread use in various applications, TiO2 has been one of the most studied materials in the twentieth century, both experimentally and theoretically.

When light shines on a semiconducting material such as TiO2, it generates either free negative (electrons) and positive (holes) charges or a bound neutral electron-hole pair, called an exciton. Excitons are of great interest because they can transport both energy and charges on a nanoscale level, and form the basis of an entire field of next-generation electronics, called “excitonics.” The problem with TiO2 so far is that we have not been able to clearly identify the nature and properties of the physical object that absorbs light and characterize its properties.

The group of Majed Chergui at EPFL, along with national and international colleagues, have shed light on this long-standing question by using a combination of cutting-edge experimental methods: steady-state angle-resolved photoemission spectroscopy (ARPES), which maps the energetics of the electrons along the different axis in the solid; spectroscopic ellipsometry, which determines the optical properties of the solid with high accuracy; and ultrafast two-dimensional deep-ultraviolet spectroscopy, used for the first time in the study of materials, along with state-of-the-art first-principles theoretical tools.

Novel semiconductor nanofiber with superb charge conductivity developed

The innovation was awarded the Gold Medal with Congratulations of the Jury at the 45th International Exhibition of Inventions of Geneva, held on 29 March to 2 April this year.

Issues to Address

Semiconductor made into nanofiber of diameter as small as 60nm (less than 1/1,000 of a human hair) have been widely used in modern daily life photonic devices (such as solar cells, photocatalyst for cleaning the environment), and non-photonic devices (such as chemical-biological sensor, lithium battery). However, electrons and holes generated by light or energy in semiconductor would readily recombine, thus reduce the current or device effectiveness. Such nature has limited the further development and applications of semiconductor nanofibers.

The novel technology developed by the research team led by Ir. Professor Wallace Leung, Chair Professor of Innovative Products and Technologies of the Department, have overcome such limitation. Applying electrospinning, the team succeeds in inserting highly conductive nano-structure (such as carbon nanotubes, graphene) into semiconductor nanofiber (such as Titanium Dioxide (TiO2) ). The novel nano-composite so produced thus provides a dedicated super-highway for electron transport, eliminating the problem of electron-hole recombination.

Amidst the potentially wide applications of the innovation in many spectrum, Professor Leung’s team has initially embarked on research of applying the novel nano-composite in two environmental aspects: solar cells, and photocatalysts for cleaning air.

Light scattering spectroscopy helps doctors identify early pancreatic cancer

The new device uses light scattering spectroscopy (LSS) to detect the structural changes that occur in cancerous or pre-cancerous cells by bouncing light off tissues and analyzing the reflected spectrum. The results could help guide physicians’ decision making when considering whether the presence of pancreatic cysts requires surgery, a high-risk procedure. Today, because of the lack of less-invasive diagnostic methods, more than half of these procedures turn out to have been unnecessary.

“About one-fifth of pancreatic cancers develop from cysts, but not all lesions are cancerous,” said Perelman, who is also Professor of Medicine and Professor of Obstetrics, Gynecology and Reproductive Biology at Harvard Medical School. “Considering the high risk of pancreatic surgeries and the even higher mortality from untreated pancreatic cancers, there’s an obvious need for new diagnostic methods to accurately identify the pancreatic cysts that need surgical intervention and those that do not.”

In Perelman and colleagues’ series of experiments, the LSS technique achieved 95 percent accuracy for identifying malignancy. Cytology — the only pre-operative test currently availably — is accurate only 58 percent of the time. While the new technique requires further testing, LSS could represent a major advance against pancreatic cancer.

“This tool is a technology that is transformative in the evaluation of pancreatic cysts,” said co-lead author Douglas K. Pleskow, MD, Clinical Chief of the Division of Gastroenterology and Director of the Colon and Rectal Cancer Program at the Cancer Center at BIDMC. “It provides a high level of precision in the detection of potential malignant transformation of these cysts.”

Scientists build new ultrasound device using 3D printing technology

With clearer images, doctors and surgeons can have greater control and precision when performing non-invasive diagnostic procedures and medical surgeries.

The new device will allow for more accurate medical procedures that involve the use of ultrasound to kill tumours, loosen blood clots and deliver drugs into targeted cells.

This innovative ultrasound device is equipped with superior resin lenses that have been 3D printed.

In current ultrasound machines, the lens which focuses the ultrasound waves are limited to cylindrical or spherical shapes, restricting the clarity of the imaging.

With 3D printing, complex lens shapes can be made which results in sharper images. The 3D printed lenses allow ultrasound waves to be focussed at multiple sites or shape the focus specially to a target, which current ultrasound machines are unable to do.

Industry partners keen to develop commercial applications

The novel ultrasound device was developed by a multidisciplinary team of scientists, led by Associate Professor Claus-Dieter Ohl from NTU’s School of Physical and Mathematical Sciences.

The ultrasound device had undergone rigorous testing and the findings have been published in Applied Physics Letters, a peer-reviewed journal by a leading global scientific institute — the American Institute of Physics.

With this breakthrough, the NTU team is now in talks with various industry and healthcare partners who are looking at developing prototypes for medical and research applications.

New radiotracer could make diagnosing prostate cancer faster and easier

Prostate cancer is the fifth leading cause of death worldwide and is especially difficult to diagnose. While prostate cancer is relatively easy to treat in its early stages, it is prone to metastasis and can quickly become deadly. In order to plan how aggressively they should treat the cancer, it is important for doctors to know how far the cancer has progressed. Currently, doctors use a variety of imaging techniques and tests to diagnose and monitor prostate cancer including PSA blood tests, magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), positron emission tomography (PET), and computerized tomography (CT) scans. Each method has strengths and weaknesses, but there is no single method that is able to successfully identify and monitor primary tumors, metastatic lymph nodes, and bone lesions.

Xiaoyuan Chen, Ph.D., Chief of the Laboratory of Molecular Imaging and Nanomedicine at NIBIB, and his team attempted to solve this problem by developing a radiotracer that could identify prostate cancer at all stages. Radiotracers are made up of carrier molecules that are bonded tightly to a radioactive atom. Like a key fitting into a lock, the carrier molecules bind to certain receptors or biomarkers and the radioactive atoms enable PET or SPECT scanners to image areas where the tracers have collected in large numbers. This new tracer targets two biomarkers, gastrin-releasing peptide receptor (GRPR) and integrin αvβ3, that often indicate prostate cancer. Previous tracers have targeted GRPR but this new tracer is one of the first dual-receptor target tracers, or tracers that target more than one biomarker, to be studied in humans.

The tracer was able to successfully identify 3 out of 4 primary tumors, all 14 metastatic lymph nodes and, significantly, was able to identity all 20 of the bone lesions in the patients. The current method of identifying bone lesions is to use the radiotracer MDP with a SPECT scanner. While this method is consistently able to identify bone lesions, it often comes up with false positives and is not able to identify primary tumors. This can cause the patient to undergo unnecessary treatments or painful biopsies.

“We are far from finding one method to diagnose and monitor prostate cancer, but this is a step in that direction,” says Chen. “Targeting multiple biomarkers could potentially allow us to identify prostate cancer at its early stages as well as after metastasis in one scan.”

Chen believes that dual-receptor targeting tracers could one day be the primary method for diagnosing and monitoring prostate cancer reducing the amount of medical scans a patient would be forced to undergo and streamlining the diagnostic and therapeutic process.