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  • richardmitnick 4:21 pm on December 29, 2017 Permalink | Reply
    Tags: Beamlne 28-ID-2 is one of the few places they could do their experiment, , , , Scintillators, We’re already able to suggest several ways to improve scintillators and samples are being made by our collaborator for our group to study, X-ray imaging, , X-rays can be harmful to patients if they are received in large or multiple doses   

    From BNL: “Scientists Solve Fundamental Puzzle in Medical Imaging” 

    Brookhaven Lab

    October 23, 2017
    Stephanie Kossman

    Researchers from Stony Brook University used the National Synchrotron Light Source II to characterize the physics of how light moves within scintillators. They’re the first group to directly measure this phenomenon. Adrian Howansky (center), a Ph.D. candidate at SBU’s Health Sciences Center, is shown holding one type of scintillator the group studied.

    Scientists from Stony Brook University (SBU) have used a novel technique at the National Synchrotron Light Source II (NSLS-II)—a U.S. Department of Energy (DOE) Office of Science User Facility located at Brookhaven National Laboratory—to answer longstanding questions in medical imaging.



    The research team used individual x-rays to characterize the physics of how light moves within scintillators—a component of x-ray detectors—for the very first time. Their findings could aid the development of more efficient x-ray detectors for improved medical diagnoses.

    X-ray imaging is a widespread technique for viewing the internal structures of matter. In the medical field, x-ray imaging is used to generate images of the body’s internal structure for diagnostic and interventional purposes. The method works by projecting x-rays though a patient and capturing them with an x-ray detector to produce a “shadow image” of the patient’s body. While x-ray imaging works similarly across all its applications, it presents a distinct problem to the medical industry.

    “There are competing challenges in medical x-ray imaging,” said Adrian Howansky, a Ph.D. candidate at SBU’s Health Sciences Center. “You want to detect as many x-rays as possible to produce a high-quality image and make the best diagnosis, but you also need to limit the number of x-rays you put through the patient to minimize their safety risk.”

    X-rays can be harmful to patients if they are received in large or multiple doses. That’s why the SBU team sought to optimize x-ray detectors by understanding the physics of how they work. If they could define the exact way these detectors produce an image, the team could identify methods for improving the images without increasing the number of x-rays sent through the patient. To do this, the scientists studied the most crucial component of the x-ray detector, called the scintillator. This material, whose thickness can be as little as 200 micrometers, is responsible for absorbing x-rays and turning them into bursts of visible light.

    “Up until our experiment here at NSLS-II, nobody has been able to precisely describe how light moves within scintillators to form an image,” Howansky said.

    Adrian Howansky is pictured with equipment at NSLS-II’s x-ray powder diffraction beamline, where the Stony Brook group conducted their research. The team’s EMCCD camera is also shown.

    What scientists did know is that when light bounces around a scintillator before it is detected, it produces “blur” that reduces image resolution. Random variations in that blur can also contribute additional noise to the x-ray image. If this phenomenon could be directly observed and understood, scientists could identify ways to improve the performance of x-ray detectors and the quality of the images they produce—and reduce the number of x-rays needed to make usable images.

    The SBU team searched for the sources of this noise by analyzing different types of scintillators at beamline 28-ID-2 at NSLS-II. Using a novel approach, the scientists imaged individual x-rays at known points in the scintillator to eliminate confounding factors.

    “By putting single x-rays at precise depths inside of the scintillators, we were able to characterize exactly how light scatters and gets collected from different points of origin. This allows us to pinpoint each source of noise in the images that scintillators make,” Howansky said. “We’re the first group to be able to directly measure this phenomenon because of the resources at NSLS-II.”

    Rick Lubinsky, an assistant research professor in radiology at SBU, said, “It’s amazing what we are able to do with the help of beamline scientists at NSLS-II. They created the perfect x-ray beam for our research—just the right energy level and just the right shape. The beam was so thin that we could actually move it up and down inside of the scintillator and resolve what was happening. The brightness and intensity of the beam is incredible.”

    NSLS-II was one of the few places the SBU team could find the high spatial resolution and variable high-energy x-rays they needed to conduct their research. “But the proposal this team brought to NSLS-II was not within the scope of the beamline’s scientific program,” said Sanjit Ghose, the beamline scientist at 28-ID-2. “The irony is that this beamline is one of the few places they could do their experiment.” Ghose and Eric Dooryhee—the group leader for the scientific program that includes beamline 28-ID-2—worked hard to ensure the SBU team would be able to conduct this critically important research at NSLS-II. Ghose noted that other scientists whose research does not fit within the scientific programs at NSLS-II beamlines can reach out to the beamline scientists to discuss research opportunities and potentially test the feasibility of their experiments.

    The Stony Brook team studies data with NSLS-II beamline scientist Sanjit Ghose. Pictured from left to right: Adrian Howansy, Rick Lubinsky, Wei Zhao, and Sanjit Ghose.

    “The arrangement of this user facility makes a lot of research possible that otherwise wouldn’t be,” said Wei Zhao, a professor of radiology and biomedical engineering at SBU.

    Now that the SBU team has gained fundamental knowledge of the physics of scintillators, they have already begun to research deeper questions, and are working with industry to produce the next generation of x-ray detectors.

    “The study has drawn attention from the medical community and our industrial collaborator that makes high resolution scintillators,” said Zhao. “We’re already able to suggest several ways to improve scintillators, and samples are being made by our collaborator for our group to study.”

    In addition to improving x-ray detectors for medical diagnoses, the results of this study [SPIE] could improve x-ray detectors across the board, including those for dental imaging, security imaging, and synchrotron science.

    See the full article here .

    Please help promote STEM in your local schools.

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    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.

  • richardmitnick 2:46 pm on November 26, 2014 Permalink | Reply
    Tags: , , , , Scintillators   

    From FNAL: “Scintillator extruded at Fermilab detects particles around the globe” 

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Wednesday, Nov. 26, 2014
    Troy Rummler

    Small, clear pellets of polystyrene can do a lot. They can help measure cosmic muons at the Pierre Auger Observatory, search for CP violation at KEK in Japan or observe neutrino oscillation at Fermilab. But in order to do any of these they have to go through Lab 5, located in the Fermilab Village, where the Scintillation Detector Development Group, in collaboration with the Northern Illinois Center for Accelerator and Detector Design (NICADD), manufactures the exclusive source of extruded plastic scintillator.

    The plastic scintillator extrusion line, shown here, produces detector material for export to experiments around the world. Photo: Reidar Hahn

    Like vinyl siding on a house, long thin blocks of plastic scintillator cover the surfaces of certain particle detectors. The plastic absorbs energy from collisions and releases it as measurable flashes of light. Fermilab’s Alan Bross and Anna Pla-Dalmau first partnered with local vendors to develop the concept and produce cost-effective scintillator material for the MINOS neutrino oscillation experiment. Later, with NIU’s Gerald Blazey, they built the in-house facility that has now exported high-quality extruded scintillator to experiments worldwide.

    “It was clear that extruded scintillator would have a big impact on large neutrino detectors,” Bross said, “but its widespread application was not foreseen.”

    Industrially manufactured polystyrene scintillators can be costly — requiring a labor-intensive process of casting purified materials individually in molds that have to be cleaned constantly. Producing the number of pieces needed for large-scale projects such as MINOS through casting would have been prohibitively expensive.

    Extrusion, in contrast, presses melted plastic pellets through a die to create a continuous noodle of scintillator (typically about four centimeters wide by two centimeters tall) at a much lower cost. The first step in the production line mixes into the melted plastic two additives that enhance polystyrene’s natural scintillating property. As the material reaches the die, it receives a white, highly reflective coating that holds in scintillation light. Two cold water tanks respectively bathe and shower the scintillator strip before it is cool enough to handle. A puller controls its speed, and a robotic saw finally cuts it to length. The final product contains either a groove or a hole meant for a wavelength-shifting fiber that captures the scintillation light and sends the signal to electronics in the most useful form possible.

    Bross had been working on various aspects of the scintillator cost problem since 1989, and he and Pla-Dalmau successfully extruded experiment-quality plastic scintillator with their vendors just in time to make MINOS a reality. In 2003, NICADD purchased and located at Lab 5 many of the machines needed to form an in-house production line.

    “The investment made by Blazey and NICADD opened extruded scintillators to numerous experiments,” Pla-Dalmau said. “Without this contribution from NIU, who knows if this equipment would have ever been available to Fermilab and the rest of the physics community?”

    Blazey agreed that collaboration was an important part of the plastic scintillator development.

    “Together the two institutions had the capacity to build the resources necessary to develop state-of-the-art scintillator detector elements for numerous experiments inside and outside high-energy physics,” Blazey said. “The two institutions remain strong collaborators.”

    Between their other responsibilities at Fermilab, the SDD group continues to study ways to make their scintillator more efficient. One task ahead, according to Bross, is to work modern, glass wavelength-shifting fibers into their final product.

    “Incorporation of the fibers into the extrusions has always been a tedious part of the process,” he said. “We would like to change that.”

    See the full article here.

    Please help promote STEM in your local schools.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics.

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