Archive for February 2016

Radiation physics today for materials science tomorrow

To the naked eye, radiation is a mysterious, invisible energy that permeates space, seemingly unimpeded, until it is either reflected or absorbed by an object. This behavior is precisely what makes radiation an excellent tool for scientists to interrogate and explore the atomic structure of materials. In the 2016 Del Favero Doctoral Thesis Prize Lecture, Mingda Li PhD ’15, a recent graduate of the Department of Nuclear Science and Engineering and a current postdoc in the Department of Mechanical Engineering, shared his perspective as a nuclear scientist on how radiation can be used to benefit society and help us understand and design new materials.

Radiation has four common roles in society: nuclear treatment (e.g. cancer radiotherapy), energy source (e.g. nuclear power plants), material exploration (e.g. microscopy), and material design (e.g. electron-beam lithography). In his address, Li envisioned a picture about how radiation byproducts, such as crystal dislocations, can be utilized to systematically alter material properties in a controllable way.

Li’s doctoral research, performed with advisors Professor Ju Li and Professor Jagadeesh Moodera, focused on developing new quantum theory to more accurately model defects in materials. Material defects interrupt the structured lattice of a crystal and, in aggregate, result in the bulk material taking on new properties. These defects can cause either favorable or unfavorable changes to the material properties. As Li described in his lecture, blacksmiths have been inducing defects in to their swords for centuries through a process called work hardening that increases their strength in battle.

Fast-forward to the modern era, and scientists like Li are envisioning new ways to precisely alter a material’s properties by inducing defects; radiation plays a dual role in this process as both a tool for exploration and design. In his work, Li has developed a new quantum theory of dislocation to allow the study of dislocations on materials’ non-mechanical properties from a fundamental Hamiltonian level. This new theory helps us understand the local impact of defects on the lattice structure and explore how placing a defect in a precision location will alter the material’s electronic properties. While scientists have many microscopy and spectroscopy techniques to physically extract this information, using computational models could allow for more rapid discovery and analysis of a wider range of materials.

A second role of radiation is to controllably induce the defects in materials. Radiation excels in this role since it can produce defects more homogeneously, with more precision, and with a higher density than comparable mechanical or chemical methods. Li envisioned that this idea of trash-to-treasure (i.e. precisely damaging a material to make it more valuable) could be utilized to produce high-defect-density materials in applications such as thermoelectrics.

Li admits, the theory and modeling of how defects alter the properties of a material is still limited to simple problems. Nevertheless, the development of new radiation physics theory today holds promise to improve our ability to explore and design materials for tomorrow. In his postdoctoral work, guided by professors Gang Chen and Mildred Dresselhaus, Li is helping to deliver on this promise.

The Del Favero Thesis Prize, established in 2014 with a generous gift from alum James Del Favero (SM ’84), is awarded annually to a PhD graduate in the Department of Nuclear Science and Engineering whose thesis is judged to have made the most innovative advance in the field.

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Medical radiation market projected to reach USD 1,234.8 million

Factors such as the increasing usage of nuclear medicine and radiation therapy for diagnosis and treatment, growing incidence of cancer, increasing safety awareness among people working in radiation-prone environments, growth of the healthcare industry worldwide, and rising insurance coverage are driving the growth of the global medical radiation detection, monitoring, and safety market.

A combination of bottom-up and top-down approaches were used to calculate the market sizes and growth rates of the global medical radiation detection, monitoring, and safety market and its subsegments. Secondary information was used to identify the overall revenues, geographic reach, and product portfolios of the market players.

Estimates of their medical radiation detection, monitoring, and safety product segment revenues were validated through primary interviews. Primary interviews with key opinion leaders were also used to determine percentage shares of each subsegment and the relative differences in the growth rates.

The report provides qualitative insights about key market shares, growth rates, and market drivers for all important subsegments. It maps the market sizes and growth rates of each subsegment and identifies the segments poised for rapid growth in each of the geographic segments.

The report also includes company profiles of the market leaders.

These company profiles include financial performances, product portfolios, and market developments for each company.

Additionally, the report provides a competitive landscape of the medical radiation detection, monitoring, and safety market. The competitive landscape covers the growth strategies adopted by industry players over the last four years.

It also includes an analysis of the industry developments, such as expansions, agreements and partnerships, acquisitions, and new product launches.

For detailed ToC,please visit:

https://www.marketstoreports.com/products/medical-radiation-detection-monitoring-safety-market-forecasts-to-2020-market-research-report

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Breaking Point: How Much Radiation Can The Human Body Tolerate?

The word radiation rarely inspires positive connotations. Despite the fact that different forms of radiation are used in medical therapies all over the world, most people think of darker occasions when presented with the word: The disaster at Chernobyl, the Three Mile Island meltdown, and the relatively recent accident at the Fukushima power plant in Japan. Though we use X-rays and other medical radiation technology without incident every day in the United States, it is the rare radiation disasters and the severe health effects they cause that stick with us.

What exactly is radiation, though, and how is it possible for us to use it for medical good and avoid it in all other situations? How do natural sources of radiation stack up to man-made ones, including the nuclear power plants many have grown to fear? What happens if we’re exposed to radiation, whether it’s a low or high dose, and whether the exposure is prolonged or acute? Here’s a look at one of the most controversial and publicized sources of harm to the human body; one that still isn’t totally understood.

A Radioactive World

There are many types of radiation in the universe, but those associated with harm to humans are usually of the ionizing variety. Ionizing radiation is energy released by atoms that travel in high frequency, short-wavelength electromagnetic waves. This type of radiation includes gamma rays, X-rays, and the highest part of the ultraviolet spectrum. This type of radiation has the power to displace electrons from their orbit around a nucleus; in terms of the human body, that means ionizing radiation can damage our DNA and other key molecular structures within the cells of our tissues and organs.

Ionizing radiation, though it’s most famously connected to nuclear meltdowns and blasts, actually comes from all sorts of materials on earth. According to the World Health Organization, “On average, 80 percent of the annual dose that a person receives of background radiation is due to naturally occurring terrestrial and cosmic radiation sources.”

These sources include naturally occurring radioactive materials on earth, such as Radon, and solar and cosmic radiation from space. Human exposure to radiation also comes from man-made activities, including medical uses of radiation treatment, mining coal and oil operations, and nuclear tests and plants.

None of this is good thing, or even an okay thing, according to most researchers. Current thinking has long-term effects of radiation exposure following a linear no-threshold hypothesis — basically, no level of exposure is safe. Even though there’s no threshold level for super-low doses of radiation, experts say there is no evidence that any level of radiation exposure is completely safe.

Based on evidence from individuals exposed to atomic bombs in Hiroshima and Nagasaki, many organizations, including the National Institutes of Health, have classified ionizing radiation as a human carcinogen. Those exposed to radiation from the bombs showed an increased risk of leukemia as well as lung, breast, ovary, and thyroid cancers. Even just receiving routine tests like X-rays or a CT scan ups a person’s cancer risk, according to the National Research Council of the National Academies. They determined that a single CT scancarries a risk of 1: 1000 of producing cancer. Though deaths from these cancers are perhaps not classified as a direct result of radiation, chronic risks of exposure have been gaining more and more attention from researchers.

This being said, we cannot escape all sources of radiation. The most severe health effects, and the only way radiation could be a direct and more immediate cause of death, come at much higher levels of exposure than any average person will experience in their lifetime.

But how much radiation is too much?

Dangerous Exposure

When we’re exposed to typical levels of radiation on a day-to-day basis, our bodies don’t even register it. Once a certain threshold of exposure is passed, however, we begin to experience an impairment in functioning. Immediate health effects of ionizing radiation exposure are grouped together under the name acute radiation syndrome (ARS). Also known as radiation sickness, ARS varies greatly in terms of symptoms and severity, depending on the dose of radiation. The effect of radiation on the body is measured in Sieverts (Sv).

Normal activities expose us to anywhere from 0.05 microsieverts (uSv) to 40 uSv — tiny fractions of what would be a dangerous dose. In terms of a onetime exposure, such as a nuclear meltdown, we begin to see negative health effects at 1 Sv. The first noticeable signs of ARS are usually nausea, vomiting, and other gastrointestinal effects, though hematopoietic effects (including a drop in blood cells), may occur first and go unnoticed without a blood test.

Radiation measured at 2 Sv can become fatal without care due to severe damage to vital organs and tissues. Once neurovascular effects, including dizziness, severe headache, and decreased levels of consciousness, occur, ARS is invariably fatal. Fatality can occur at 4 Sv without prompt treatment, and occurs without fail at 8 Sv.

So what do these levels of exposure look like in real-life terms? Ten minutes next to the reactor core at Chernobyl after meltdown would have resulted in 50 Sv of exposure, well beyond the lethal dose for humans. Aside from actually standing next to the biggest nuclear disaster in history, however, it’s unlikely a person will ever come across such high levels of exposure. Even radiation workers have a recommended limit of less than 0.05 Sv per calendar year.

Barring any extenuating circumstances like atomic bombs or nuclear explosions, ARS should be a very, very distant concern for most people. The longer-term effects of radiation, most notably the increased risk of cancer, are a much more relevant problem. Though there’s no way to avoid all radiation, simple precautions like wearing lead for X-rays and getting your home checked for Radon can decrease one’s risk of developing cancer from radiation exposure.

*Posted from www.medicaldaily.com 

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