Connect with us

Health

What’s the lowdown on the radiation from all those CT scans

Published

on

[ad_1]

An X-ray for knee pain. A CT scan for a head injury. Mammograms every other year, starting at age 50. Over a typical lifetime of radiation exposure from medical tests, a person can start to wonder: How much is too much?

There’s no formula for answering that, experts say, in part because the health effects of radiation don’t add up in a linear way. And while massive doses of radiation are known to be harmful, the small doses used in routine tests are usually safe, especially compared with other health-care choices people make without thinking twice.

Researchers are looking into the potential health ramifications from CTC scans.
Researchers are looking into the potential health ramifications from CTC scans.  (Norman Pogson / Dreamstime)

“Radiation does have some risk,” says Russ Ritenour, a medical physicist at the Medical University of South Carolina in Charleston. “But it is important for medicine. And in most cases, the risk is quite small compared to the risk of taking too much Advil over your life and other things like that.”

Ionizing radiation — the type that can damage cells — is a daily fact of life even for people who never go to the doctor. Rocks and soil contain radioactive materials, which also appear in our food, our bones and the air we breathe. Cosmic rays barrage us with radiation from space, with higher doses at altitude and on airplanes.

Overall, a person in the United States gets an annual average of about 3 millisieverts (mSv) of background radiation. (Millisieverts are units that measure radiation absorbed by our bodies.)

Added exposure, totalling another 3 mSV each year for the average American, comes from such man-made sources as power plants that run on coal and nuclear fuel, and consumer products including TVs and computer screens. But most of the extra radiation we get comes from X-rays and CT scans, Ritenour says.

Most routine diagnostic tests emit extremely small amounts of radiation. A patient will get about 0.001 mSv from an arm X-ray, 0.01 mSv from a from a panoramic dental X-ray, 0.1 mSv from a chest X-ray and 0.4 mSv from a mammogram, according to Harvard Medical School. (Those estimates vary somewhat, depending on the source and on the specific device used, the size of the patient and other factors.)

CT scans, which take multiple X-rays to create cross-sectional images, deliver higher doses: 7 mSv for a chest CT, and 12 mSV for a full-body scan, according to the National Cancer Institute. Studies have found doses of 25 mSv or more from a PET/CT, an imaging test that requires ingesting a radioactive substance.

With the increasing availability and affordability of imaging technologies, people are getting more tests than they used to. Today, Americans receive more than 85 million CT scans each year, compared with 3 million per year in the 1980s.

Many of those tests may be excessive, argue some researchers, who have been trying to quantify the risks of our increasing use of ionizing radiation in medical imaging. A 2009 study by scientists at the National Cancer Institute estimated that 2 per cent — or about 29,000 — of the 1.7 million cancers diagnosed in the United States in 2007 were caused by CT scans. In a 2004 study, researchers estimated that a 45-year-old who planned to get 30 annual full-body CT exams would have a nearly 2 per cent lifetime risk of dying of cancer. Other studies are underway to clarify risks, including in children.

But evaluating an individual’s chances of experiencing a bad outcome from any given test or a combination of tests is tricky. Some of the most definitive data on radiation’s health effects come from long-term studies of tens of thousands of people who survived the atomic bombings of Hiroshima and Nagasaki in 1945. Sudden exposure to 1,000 mSv, those studies have found, increased the risk of getting cancer by 42 per cent and increased the risk of dying of cancer by 5 per cent.

Risks of secondary cancers also rise with the high doses of radiation used in some cancer treatment — a trade-off that often makes sense because doing nothing would be even riskier.

Evidence is murkier about health consequences from lower doses. The Food and Drug Administration estimates that 10 mSv of radiation, an amount typical for a CT of the abdomen, increases lifetime cancer risk by 1 in 2,000. But that calculation assumes that risks are proportional to dose, which has not been proved. Below 10 mSv, there is not enough good data to draw clear conclusions.

There is also no absolute number of scans that constitute a tipping point for health, Ritenour says, in part because our bodies have repair mechanisms that can fix cells damaged by radiation. So while every scan adds to the chances that a problem will occur, radiation doesn’t build up in the body. And damage doesn’t accumulate like water poured into a glass. Theoretically, he adds, 10 mammograms in one day would be riskier than one mammogram a year for 10 years.

“All you can really say is that there’s very little chance a problem can happen” at low doses, says Ritenour, who often consults with patients who have questions about radiation. “It is very unsatisfying in a way. You can’t say, ‘You will definitely have no problems.’ ‘’

Although health risks from most imaging tests are extremely small, fear can be hard for people to rationalize away. There is a one-in-a-million chance of getting cancer from a chest X-ray, Ritenour says, the same tiny chance of getting cancer from toxins in peanut butter.

Making decisions about diagnostic tests ultimately requires comparing their potential benefits with their potential harms. That balance can be easy to measure if someone has a broken leg or a bullet fragment lodged in their body. But decisions become more nuanced for tests such as mammograms, which catch breast cancers in some women but also produce false alarms that cause unnecessary anxiety and followup testing that entails even more radiation. Given the trade-offs, the U.S. Preventive Services Task Force offers evidenced-based advice about many screening tests, and those guidelines can be helpful starting points for conversations with your doctor.

Online calculators can also offer food for thought. When I entered my location, estimated miles travelled by airplane and other information into a tool maintained by the Nuclear Regulatory Commission, I learned that I absorb an estimated 318 millirems, or 3.18 mSv, of radiation each year. Each millirem, according to this government agency, equates to a 1.2-minute reduction in life span, the same accrued from eating 10 extra calories (assuming I’m overweight) or crossing the street three times. In other words, I am likely to die 41/2 hours sooner than I would if I could avoid radiation altogether.

While some researchers work to better understand and communicate the risks of radiation, others are refining technologies and procedures, adds Louis Wagner, a diagnostic medical physicist at McGovern Medical School at the University of Texas Health Science Center at Houston. And the field has come a long way.

For example, after studies found an elevated risk of breast cancer among women who had received X-rays for childhood scoliosis, experts say, many health centres switched from taking images from the front of the body to taking images from behind to reduce the cancer risk.

Technicians have made mistakes, such as using higher doses of radiation than needed during scans, and some mistakes have led to expensive legal cases, Wagner says. But those cases are rare. And most machines are now equipped with safety features to avoid overexposure.

“The profession has sought to make use of radiation very, very beneficial to patients with minimal and, I believe, unrecognizable risks,” Wagner says. “I want patients to know the medical profession is avidly pursuing better ways to use radiation to increase the benefits-to-risks ratio. I think good progress is being made.”

[ad_2]

Source link

قالب وردپرس

Health

Post-vaccine surge? Michigan’s spring coronavirus case spike close to previous year’s autumn high

Published

on

By

(Natural News) The spike in new Wuhan coronavirus infections recorded in Michigan over the spring is similar to a spike seen during the 2020 fall season. According to a Wall Street Journal analysis, the state’s daily coronavirus case count averaged more than 7,000 for almost two weeks – before taking a slight dip to 6,891 on April 20. This echoed similar figures back in November and December 2020, which saw sharp rises in infections for those two months before plunging.

Back in autumn of last year, Michigan averaged more than 7,000 cases per day for a span of 10 days. New infections dropped slightly, then briefly spiked as the December holidays approached. It then fell to the low 1,000s for the succeeding two months – until ascending again in March.

According to University of Michigan internal medicine professor Dr. Vikas Parekh, the sudden increase in new infections could be attributed to several factors. Among the factors he cited was re-openings, which increased people’s interactions and mobility. Parekh said the loosened restrictions contributed to the spread of the highly contagious U.K. B117 variant.

“As the B117 variant spreads nationally, we will likely see other stats [with] their own surges – although I hope none are as bad as Michigan,” the professor remarked. He continued: “The milestone just tells us we are not yet in the clear, especially as we still have large portions of our population who are not vaccinated yet.”

Parekh also expressed optimism over the lower daily caseloads the Great Lakes State reported. He said he believes both cases and hospitalizations have plateaued and will likely decline soon. The professor commented: “[COVID-19] positivity has been declining now for one week, which is usually a leading indicator of case decline.”

Meanwhile, the state cited younger populations and youth sports, such as basketball, wrestling and hockey, to increase new COVID-19 infections. Because of this, Gov. Gretchen Whitmer called to suspend youth sports and indoor dining in the state. She also exhorted high schools to conduct remote class sessions for two weeks to curb the spread of the pathogen.

Michigan still experienced the spike in cases despite having one of the highest vaccination rates in the country

During the opening stages of the U.S.’s immunization drive against COVID-19, Michigan boasted of having one of the highest vaccination rates nationwide. A report by Bridge Michigan even noted the initial “frenzy for vaccines” that “far exceeded the state’s limited supply.” But things have appeared to turn around for Michigan, as it now struggles to reach the 70 percent vaccination rate needed for herd immunity.

Continue Reading

Health

Scottish mom’s legs turn into a pair of “giant blisters” after first dose of AstraZeneca’s coronavirus vaccine

Published

on

By

(Natural News) Sarah Beuckmann of Glasgow, Scotland, felt a tingling sensation in her legs and noticed a rash flaring up around her ankles a week after getting her first dose of AstraZeneca’s coronavirus (COVID-19) vaccine on March 18.

She also had flu-like symptoms right after the vaccination.

Beuckmann called her doctor to arrange an appointment the morning she noticed the rash, but by the afternoon her skin was already breaking out into blood-filled blisters. Blisters also appeared on her legs, hands, face, arms and bottom.

“I ended up asking my husband to take me to A&E,” said Beuckmann, referring to “accident and emergency,” the equivalent of an emergency room (ER). “When I got there, my heart rate was sitting at 160bpm, which they were very concerned about. I got put on an ECG machine.”

Doctors determine AstraZeneca’s COVID-19 vaccine triggers the rash

Medics carried out tests for HIV, herpes and other skin conditions to work out what triggered the rash, but all results came back negative. Doctors finally determined that the vaccine caused her rare reaction after carrying out two biopsies.

“Once they found that it was a reaction to the vaccine, they put me on steroids and that really seems to be helping my progress,” said Beuckmann. She had been advised by her doctor not to get the second dose of AstraZeneca’s COVID-19 vaccine because of her reaction.

Beuckmann spent 16 days at Queen Elizabeth University Hospital. She was discharged to recover at home. The 34-year-old mother of one is currently wheelchair-bound due to the bandages on her legs and blisters on the soles of her feet. She may need physiotherapy to help strengthen her leg muscles.

“They are starting to heal and they’re looking a lot better than they were but as the blisters started to get worse, they all sort of merged together,” she said. “I didn’t know what was going on.”

With the blisters merging, her legs have looked like a pair of “giant blisters.” Beuckmann admitted that at one point she feared her legs might have to be amputated.

Dermatologist agrees COVID-19 vaccine causes the blisters

Dr. Emma Wedgeworth, a consultant dermatologist and spokeswoman at the British Skin Foundation, agreed that Beuckmann had likely suffered a reaction to the vaccine.

“Vaccines are designed to activate the immune system. Occasionally people will have quite dramatic activation of their immune systems which, as happened in this case, can manifest in their skin” Wedgeworth told MailOnline. “This poor lady had a very severe reaction, which thankfully is extremely rare.”

It is not clear why Beuckmann, who works in retail, was invited for a vaccine. Scotland’s vaccine rollout was focused on people over the age of 50 when she got vaccinated, although vaccines are available to those who are considered at risk from the virus, or live with someone considered vulnerable.

At least 20 million Briton have had AstraZeneca’s COVID-19 vaccine, which drug regulators say causes a rash in one percent of cases. They say rashes caused by the jab tend to go away within a week.

Continue Reading

Health

Trojan labs? Chinese biotech company offers to build COVID testing labs in six states

Published

on

By

In 2012, BGI acquired Complete Genomics, a DNA sequencing company and equipment maker. The funds for the $117.6 million purchase were raised from Chinese venture capitals. The company has expanded its footprint globally. According to its website, BGI conducts business in more than 100 countries and areas and has 11 offices and labs in the U.S.

People are concerned about China’s access to American DNA data

Some said that with Complete Genomics providing an American base, BGI would have access to more DNA samples from Americans, helping it compile a huge database of genetic information. Some also worried about the protection of the genetic information’s privacy.

According to a 2019 report from the U.S.–China Economic and Security Review Commission (USCC), BGI “has formed numerous partnerships with U.S. healthcare providers and research organizations to provide large-scale genetic sequencing to support medical research efforts,”

There are three main reasons why many people in the biotech community and government have expressed concerns about China’s access to American DNA data.

In the “60 Minutes” interview, Evanina discussed the very likely scenario in which Chinese companies would be able to micro-target American individuals and offer customized preventative solutions based on their DNA.

Evanina asked: “Do we want to have another nation systematically eliminate our healthcare services? Are we okay with that as a nation?”

The second concern is that China may use DNA to track and attack American individuals. As the USCC report states: “China could target vulnerabilities in specific individuals brought to light by genomic data or health records. Individuals targeted in such attacks would likely be strategically identified persons, such as diplomats, politicians, high-ranking federal officials or military leadership.”

The third concern is that China may devise bioweapons to target non-Asians. Steven Mosher, president of the Population Research Institute, discussed it in his article “What Will China Do With Your DNA?” published by The Epoch Times in March 2019.

He wrote: “We know that the Asian genome is genetically distinct from the Caucasian and African in many ways. … Would it be possible to bioengineer a very virulent version of, say, smallpox, that was easily transmitted, fatal to other races, but to which the Chinese enjoyed a natural immunity? … Given our present ability to manipulate genomes, if such a bio-weapon can be imagined, it can probably – given enough time and resources – be realized.”

An article from Technocracy said: “China’s aggressive collection of American DNA should be doubly alarming because it can only spell one ultimate outcome: biowarfare. That is, genetically engineering viruses or other diseases that will be selectively harmful to U.S. populations.”

Continue Reading

Chat

Trending