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Posts Tagged ‘Radiation’

Cross checking through the patient’s total past exposure, and then carefully weighing the risks and benefits of each test and any alternative approaches that can be taken is a good approach to reduce excessive Radiation Risks.

There are two new studies appearing in the Tuesday’s issue of the journal Radiology which suggested more physicians should take this approach. It was also found in a recent study that certain nuclear-based breast imaging exams that involve injecting radioactive material into patients expose women to far higher doses of radiation than regular mammography, increasing their risk of cancer in vulnerable organs beyond the breast, like the kidneys, bladder or ovaries. Over all, the United States population’s annual radiation dose from medical procedures increased sevenfold between 1980 and 2006, a second paper reports.

A latest article published by Roni Caryn Rabin in The New York Times shows how Dr. Deborah Rhodes approaches radiation tests is a remarkable study. Before she orders for a diagnostic test that involves radiation, she consults a chart in her office that lists the amount of radiation exposure from each test. She considers the patient’s total past exposure, and then carefully weighs the risks and benefits of each test and any alternative approaches she can take. “I’m a radiation phobe — I’ll come right out and say this,” said Dr. Rhodes, an internist at the Mayo Clinic who is doing research to develop screening technologies that require less radiation exposure to the patient. “I’m constantly monitoring radiation doses in my patients.”

She also mentioned, “this is something that isn’t well understood, not just by the public — but by physicians who order the tests.” R. Edward Hendrick is a physicist who has studied breast imaging for almost 30 years, said he was motivated to quantify the radiation exposure from nuclear breast imaging technologies in a published paper because of similar concerns.

“I would go to the international breast meeting and the big radiology meetings, and nobody had a clue what the doses and risks were,” Dr. Hendrick said. “They’re treating all the tests as if they have the same radiation dose and risk as mammography, and the truth is they have a much, much higher risk. The point of the paper was to say that not all the breast imaging procedures have comparable risks and doses.”

Dr. Hendrick who is a clinical professor of radiology at the University Colorado-Denver School of Medicine in Aurora, Colo., is also a consultant to G.E. Healthcare regarding digital breast tomosynthesis, another breast imaging technique, and is on the medical advisory boards of Koning and Bracco, which make other imaging technologies. The nuclear technologies breast-specific gamma imaging (B.S.G.I.) and positron emission mammography (P.E.M.) are meant to be used as complements or adjuncts to mammography and ultrasound, once there is concern about a cancerous lesion, and not for routine screening. These technologies are also more useful in women who have very dense breast tissue, when mammography often does not provide clear images.

It is noticed that a single breast-specific gamma imaging or positron emission mammography exam exposes patients to a risk of radiation-induced cancer that is comparable to the risk from an entire lifetime of yearly mammograms starting at 40, according to Dr. Hendrick’s study. While digital mammography has an average lifetime risk of inducing 1.3 fatal breast cancers per 100,000 women aged 40 at exposure, a single B.S.G.I. exam was estimated to involve a lifetime risk 20 to 30 times greater in women aged 40, and the lifetime risk of a single P.E.M. was 23 times greater.

Moreover, mammography only increases a woman’s risk for breast cancer while B.S.G.I. and P.E.M. increase the risk of cancer in other organs, such as the intestines, kidneys, bladder, gallbladder, uterus, ovaries and colon, the recent study declared. There is also a concern that use of the imaging technologies will become more widespread and casual. “B.S.G.I. and P.E.M. are great tools for problem solving, if you have a patient with an abnormal mammogram and you’re not really sure,” said Dr. Rhodes. “The problem is these tests are now being considered and even being used in some cases as screening tests, and this is not appropriate.”

“I’m not saying ‘Don’t do the test,’ I’m just saying ‘Don’t prescribe these tests willy-nilly like you would an ultrasound exam,’ ” Dr. Hendrick said.

A few suggested proposals namely for curbing excessive use of imaging include developing national evidence-based appropriateness criteria for imaging, educating referring physicians and the public, curbing the physician practice of self-referral and finding ways to reduce duplicate exams. William R. Hendee, a distinguished professor of radiology, radiation oncology, biophysics and bioethics at the Medical College of Wisconsin in Milwaukee, called on radiologists to spearhead a campaign to reduce overuse of imaging technologies that expose patients to radiation unnecessarily and drive up health costs in the process

“The comparison to mammography is a bit like comparing apples to oranges,” said Doug Kieper, vice president of science and technology for Dilon Technologies Inc., which developed the B.S.G.I. technology. “This is not being used as a screening procedure for the general asymptomatic population who have no indication of disease.” He added that studies were already under way to see if the same results could be obtained using lower doses of radiation.

For patients with brain tumors who don’t have a variety of option have to settle with a surgery and radiation which can damage crucial parts of the brain. It is also seen that the chemotherapy drugs don’t easily percolate through the blood-brain barrier.

An effective solution is being launched where a procedure using magnets, ultrasound and minuscule drug-coated particles may be an effective solution, published in Tuesday’s edition of the journal Proceedings of the National Academy of Sciences.

The researchers, led by Dr. Kuo-Chen Wei of Chang Gung University in Taiwan, injected tiny magnetic beads called nanoparticles, coated with a chemotherapy drug, into the rats’ tails. Ultrasound was used to open up a small region of
the blood-brain barrier and a magnetic field to attract the particles to an actual location in the brain. This procedure of treating rats with brain tumors resulted in slowing the tumor growth in rats lived two-thirds longer than untreated rats.

“The technology’s not very difficult,” Wei said, “but the idea is novel.”He also added that clinical trials in human beings are at least four to five years away.

It becomes difficult to treat brain tumors to treat with traditional drug delivery methods because the brain is insulated from circulating blood. The focused ultrasound which is much stronger than the ultrasound technique used on pregnant women temporarily disrupts the barrier and also allows drugs to enter.

Once the drugs get into the brain, It should be properly allotted to the actual places to cut down on the damage to healthy tissue. This report is the first in which magnetic targeting was combined with ultrasound to attract the nanoparticles and their drug passengers to a specific part of the brain.

“The method has significant clinical potential,” said Dr. Kullervo Hynynen of the University of Toronto Medical School, who conducts similar research but was not involved in the new study.

Wei and his team are working to improve the treatment so that it can be also used on humans. He declared that first additional chemotherapy drugs and nanoparticle types had to be tried, as well as improve the ultrasound and magnetic-targeting technology. Some scientists still are under the impression that opening the blood-brain barrier to allow powerful chemicals into the brain is too dangerous on humans.

“The potential for toxicity in normal brain regions could cause all kinds of problems,” said Allan David, a drug delivery researcher at the University of Michigan. “I think it’s an interesting study, but it’s still far from clinical studies.”

Some amount of danger in opening the blood-brain barrier can be avoided by combining Wei’s approach with a type of drug that is activated only upon reaching the tumor, David said, so that healthy brain tissue is left unharmed.

biospace med has announced that the company’s lead product, EOS ultra-low-dose 2D|3D imager, has been proven to reduce patient’s radiation exposure by upto 89 percent when compared to conventional computed radiography systems.

The findings of the study are published in the latest issue of the ‘Spine’ journal. The principal investigator of the 50 patient clinical study was Dr. Stefan Parent, M.D., Ph.D. from the Centre Hospitalier Universitaire Sainte-Justine, Montreal.

The study enrolled 9 girls and 11 boys with an average age of 14 and 8 years who were being followed up for spinal abnormalities. All patients recieved a CR (Computed Radiography) x-ray exam and an EOS exam for which skin dose was measured at skin level by dosimeters in 13 anatomical areas.

The study found that the quality of an EOS image is equal to or better than conventional or a CR x-ray system and exposes patient to upto 9 times lesser radiation.

EOS ultra-low-dose 2D|3D imager, developed by biospace med, is a new technology in orthopedic x-ray imaging and is used in the diagnosis and follow-up of bone and joint disorders, particularly spinal deformities. It can take local as well as whole body images; can also generate two dimensional or three dimensional images of the skeleton. The system allows full-body imaging of patients in sitting as well as in weight-bearing position that enables global assessment of balance and posture.

EOS has recieved approval from the FDA for use in adults and children and is now available in Europe and the USA.

Scientists plan to take-up their concerns, regarding radiation hazards from excessive radiology procedures, to the public on tuesday at a Food and Drug Administration (FDA) meeting, The New York Times reports.

The two-day public meeting (March 30th and 31st) is called by FDA to evaluate the issues regarding unnecessary radiation exposure from routine procedures and to discuss steps devicemakers can take to reduce patient exposure to radiation.

The report states that according to reports from FDA and interviews with the agency scientists, the FDA has ignored warnings from government experts regarding riskes from powerful Computed Tomography (CT) scans used for colo-rectal cancer screening.

Cancer risk from unnecessary radiology diagnostic procedures, doctors prescribing unneccesary scans, lack of standardization of CT scanners and other radiation emitting equipment are all much debated issues nowadays with regard to reducing radiation exposure. Use of CT scans for cancer screening in healthy adults is another hot topic.

The average life time dose of diagnostic radiation has increased around 7 times in the last thirty years. The increasing popularity of CT scans, driven by overzealous doctors and companies, is in particular a cumulative factor for this. The radiation emitted by a single whole body scan is equivalent to that emitted by about 500 conventional x-rays. Studies have showed that CT scans increase the cancer risk by about 0.05 percent.

New York Times reports that it is a very difficult position for the patients side because doctors, patient advocacy groups and manufacturers advocate these tests for their econimic interests; radiologists who own and use equipment favour the tests while patient groups are funded by manufacuters or physician groups.

Also the FDA, who has to sort out the issue, is also divided with internal dispute, the newspaper says. A group of agency scientists might testify that the FDA managers ignored their concerns thereby endangering the public.