Archive | Radiation

Deep-space Magnetic Fields Described

LOS ANGELES, Sept. 21 (UPI) — Evidence of “universal ubiquitous magnetic fields” permeating deep space between galaxies since the Big Bang has been discovered, U.S. astronomers say.

For many years physicists have hypothesized a universal magnetic field should exist in deep space between galaxies, but there was no way to observe it or measure it until now.

Caltech physicist Shin’ichiro Ando and UCLA astronomer Alexander Kusenko studied images of the most powerful objects in the universe — supermassive black holes that emit high-energy radiation as they devour stars in distant galaxies — obtained by NASA’s Fermi Gamma-ray Space Telescope, a UCLA release said.

After producing a composite image of 170 giant black holes, they discovered the images were not as sharp as expected.

Background radiation left over from the Big Bang could account for some — but not all — of the distortion, they said.

But “even a small magnetic field along the way can deflect the electrons and positrons, making the image fuzzy,” they said.

Using the images, they calculated the average magnetic field as just one-quadrillionth the strength of Earth’s field.

This universal magnetic field may have formed in the early universe shortly after the Big Bang, long before stars and galaxies formed, Ando and Kusenko said.

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Shortage of Medical Isotopes a Concern

BOSTON, Sept. 8 (UPI) — A global shortage of radioactive isotopes used in medical scans and treatments could jeopardize patient care and drive up healthcare costs, scientists say.

The warning was delivered in a symposium at the annual meeting of the American Chemical Society in Boston, a society release said.

“Although the public may not be fully aware, we are in the midst of a global shortage of medical and other isotopes,” Robert Atcher, director of the National Isotope Development Center at the Los Alamos National Laboratory in New Mexico, said in an interview.

“If we don’t have access to the best isotopes for medical imaging, doctors may be forced to resort to tests that are less accurate, involve higher radiation doses, are more invasive, and more expensive.”

Medical isotopes are minute amounts of radioactive substances used to diagnose and treat a variety of diseases, including heart disease, cancer, and gallbladder, kidney and brain disorders.

More than 50,000 patients a day in the United States receive diagnostic and therapeutic procedures using medical isotopes, scientists say.

Eight out of every 10 procedures require one specific isotope, technetium-99m, which has a “half-life” of only 6 hours.

Half-life is the time it takes for 50 percent of a given quantity of a radioactive substance to “decay” and disappear. Like other radioactive isotopes, technetium-99m can’t be stockpiled. It must be constantly made fresh, and distributed quickly to medical facilities, scientists say.

U.S. supplies of technetium have been low for the past 15 months, ever since its main supplier, a Canadian nuclear reactor, shut down temporarily.

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

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Study Says Sheltering Better Nuclear Plan

WASHINGTON, Sept. 7 (UPI) — A U.S. study says that in a nuclear detonation people in large cities would be better off sheltering in place rather than trying to evacuate immediately.

Researchers at Stanford University say that unless a lengthy warning period is provided, clogged exit roads would pose more significant risks by exposing evacuees to radiation than if people were to remain in place at the center of large buildings or in basements, a release from the Society for Risk Analysis says.

The Stanford research uses sophisticated mathematical models to investigate the impact of various response strategies.

“The logistical challenge of an evacuation appears to be beyond current response capabilities,” study author Lawrence M. Wein of Stanford said.

The Stanford researchers cite previous studies saying first responders are unlikely to be able to establish evacuation stations until 12-48 hours after an attack, no significant federal response would be likely for 24 hours, and a full federal response is not likely to be achieved for 72 hours.

“Unlike a bioterror or chemical attack, it may not be possible for the government to provide timely advice to the populace after such an event,” the study said.

The research was published in the journal Risk Analysis.

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Lasers Could Protect Helicopters from Harm

ANN ARBOR, Mich., Sept. 3 (UPI) — A new laser technology could protect helicopters in combat from heat-seeking missiles, University of Michigan researchers say.

Using inexpensive, off-the-shelf telecommunications fiber optics, Mohammed Islam, a professor in the UM Department of Electrical Engineering and Computer Science, has developed sturdy and portable “mid-infrared supercontinuum lasers” that could blind heat-seeking weapons from a distance of 1.8 miles, a university release said.

“Battlefield terrain in places like Afghanistan and Iraq can be so rough that our troops have often had to rely on helicopters, and they can be easy targets for enemies with shoulder-launched missiles,” Islam says.

“Our lasers give off a signal that’s like throwing sand in the eyes of the missile.”

The lasers are promising for helicopter protection because their robust, simple design can withstand the vibrations of helicopter flight.

Most lasers emit light of just one wavelength. But supercontinuum lasers give off a focused beam packed with light from a much broader range of wavelengths.

Islam’s mid-infrared supercontinuum laser is the first to operate in longer infrared wavelengths that heat-seeking missiles use to home in on the infrared radiation that a helicopter engine emits.

By emitting a broad spectrum of infrared light, it can effectively mimic the engine’s electromagnetic signature and confuse any incoming weapons, Islam said.

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

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NASA Plans Close Encounter with the Sun

WASHINGTON, Sept. 3 (UPI) — NASA has started development of Solar Probe Plus, a mission to study the sun more closely than ever before, with a target launch date of 2018, the agency says.

The spacecraft will plunge directly into the sun’s atmosphere at approximately 4 million miles from the sun’s surface, into a region that no other probe has ever encountered, an agency release said.

The mission will carry five separate science investigations hoping to discover more about our sun than any previous mission, NASA said.

“The experiments selected for Solar Probe Plus are specifically designed to solve two key questions of solar physics — why is the sun’s outer atmosphere so much hotter than the sun’s visible surface and what propels the solar wind that affects Earth and our solar system? ” Dick Fisher, director of NASA’s Heliophysics Division in Washington, said.

“We’ve been struggling with these questions for decades and this mission should finally provide those answers.”

A revolutionary carbon-composite heat shield will withstand temperatures exceeding 2,550 degrees Fahrenheit and blasts of intense radiation as the spacecraft approaches the sun.

NASA has earmarked $180 million for preliminary analysis, design, development and tests of the mission’s science experiments.

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

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Scientists 'listen' to Paint Pigments

MONTREAL, Sept. 2 (UPI) — A new technique that can “hear” the sound of colors may help art restorers identify the pigments in centuries-old paintings, researchers say.

Canadian scientists at McGill University in Montreal say a technique called photoacoustic infrared spectroscopy can cause the pigments used in artists’ colors to emit sounds when light is shone on them, a university release said Wednesday.

“The chemical composition of pigments is important to know, because it enables museums and restorers to know how the paints will react to sunlight and temperature changes,” said Ian Butler, a professor at McGill’s Department of Chemistry.

The spectroscopy method is based on Alexander Graham Bell’s 1880 discovery that solids could emit sounds when exposed to sunlight, infrared radiation or ultraviolet radiation.

The McGill researchers are the first to use it to analyze typical inorganic pigments that most artists use.

The researchers have classified 12 historically prominent pigments by the infrared spectra they exhibit – in other words, the range of noises they produce – and hope the technique will be used to establish a pigment database.

“Once such a database has been established, the technique may become routine in the arsenal of art forensic laboratories,” Butler said.

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

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Silicone Oil May Help Treat Eye Cancer

AURORA, Colo., Aug. 31 (UPI) — Silicone oil applied inside the eye can block up to 55 percent of harmful radiation to prevent blindness in patients with eye cancer, a U.S. researcher says.

Dr. Scott Oliver, an assistant professor at the University of Colorado School of Medicine, says eye cancer, a rare but devastating disease, can strike anyone — although fair skin and sun exposure can increase risk — at any time, and treatment often requires radiation that leaves half of all patients partially blind.

Oliver focused on choroidal melanoma of the eye, or uveal cancer, the most common and dangerous form of eye disease, which affects some 2,000 people annually. It can spread quickly to the liver and lungs and often can be fatal.

For treatment, physicians often use plaque brachytherapy in which surgeons attach a gold cap containing radioactive seeds to the white part of the eye.

“Radiation injures blood vessels and nerves in the back of the eye,” Oliver says in a statement. “Half of all patients are legally blind in 3 years in the treated eye.”

Oliver tried several substances to block radiation from striking critical structures while allowing it to hit the tumor.

The study, published in the Archives of Ophthalmology, finds silicone oil — already used to treat retinal detachment — could screen out a majority of harmful radiation.

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

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New Imaging Linked to Higher Cancer Risk

DENVER, Aug. 25 (UPI) — A U.S. researcher says two new nuclear-based breast imaging exams increase cancer risk.

R. Edward Hendrick of the University of Colorado-Denver School of Medicine says the technologies — known as breast-specific gamma imaging and positron emission mammography — involve the injection of radioactive material into the patient.

“A single breast-specific gamma imaging or positron emission mammography examination carries a lifetime risk of inducing fatal cancer greater than or comparable to a lifetime of annual screening mammography starting at age 40,” Hendrick says in a statement.

The study, published in Radiology, estimates a single breast-specific gamma imaging involves a lifetime risk of fatal cancer 20 to 30 times that of digital mammography in women age 40 years and older, while the lifetime risk of a single positron emission mammography was 23 times greater than that of digital mammography.

Additionally, the newer technologies may not only increase the risk of breast cancers but also of cancers in other organs, Hendrick says.

Hendrick bases his calculations for lifetime risks of radiation-induced cancer incidence on a review of recent studies on radiation doses from radiologic procedures and organ doses from nuclear medicine, along with age-dependent risk data.

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

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U.S. Rectal Cancer Increasing in Young

PHILADELPHIA, Aug. 25 (UPI) — Rectal cancer rates are increasing in people age 40 and under across races and in both sexes, U.S. researchers said.

Study leader Dr. Joshua Meyer, a radiation oncologist at Fox Chase Cancer Center, analyzed trends in U.S. rectal cancer compared with colon cancer trends. Dr. Meyer worked on the study while at the New York-Presbyterian Hospital/Weill Cornell Medical Center in New York City.

Using data from the Surveillance Epidemiology and End Results cancer registry, the researchers identified 7,661 colon and rectal cancer patients age 40 and under between 1973 and 2005.

The study, published in the journal Cancer, finds overall rates of colon cancer and rectal cancer were low during the study — 1.11 cases per 100,000 for colon cancer and 0.42 cases per 100,000 for rectal cancer.

Colon cancer rates remained essentially flat in people age 40 and under in recent decades but rectal cancer rates from 1984 to 2005, rose 3.8 percent per year.

“We suggest that in young people presenting with rectal bleeding or other common signs of rectal cancer, endoscopic evaluation should be considered in order to rule out a malignancy,” Meyer said in a statement. “This is in contrast to what is frequently done, which is to attribute these findings to hemorrhoids.”

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Study: Some Cancer Patients Not Given Drug

ALBUQUERQUE, Aug. 19 (UPI) — Many elderly U.S. cancer patients were not given a drug that could improve chances of survival sixfold out of concern for minor side effects, a study says.

Researchers at the University of New Mexico Cancer Center say oncologists showed reluctance to prescribe the drug imatinib for older sufferers of chronic myeloid leukemia, a relatively rare form of blood cancer diagnosed in about 4,500 new patients a year, The Albuquerque Journal reported Thursday.

Age disparity has long been recognized as a factor in cancer therapy, because many treatments, such as radiation and chemotherapy, tend to be highly toxic, Dr. Robert Hromas, chief of hematology oncology for the UNM Cancer Center and lead author of the study, said.

Many physicians believe elderly patients would have trouble surviving such treatments.

But in the case of imatinib, Hromas said, “the drug is very non-toxic and everybody knew it was non-toxic.”

The study examined outcomes of 423 patients diagnosed with CML in six states, including New Mexico, and in six metropolitan areas across the nation.

Researchers found an “age disparity” most apparent in patients 80 and older, only 47 percent of whom received imatinib.

The study speculates physicians may not have known imatinib is safe for older people because results of clinical trials were not reported by age

The study authors urged all federally funded clinical trials include older patients and that reports of the trials include data about older patients.

“If you’re an elderly patient, ask your oncologist,” Hromas said.

“Make sure you’re getting the latest therapy, because there’s a resistance to giving the latest therapy to elderly cancer patients.”

Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.

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