- Are radiologists exposed to dangerous levels of radiation?
- Radiation risk from medical imaging
- Busted: Three Common Myths About Radiologic Technology
- Does Low-Dose Radiation Pose a Threat to Radiologic Technologists?
- Radiologists do not face elevated risk of radiation-related mortality
- Radiation Protection for Radiologic Technicians
- Risks of Radiation
- Weighing the Radiation Risks of CT, X-ray and Other Imaging
- Risks of Radiation vs. Benefits of Radiation
- Alternative Perspective Regarding Risk
- Risks in Context
- Risk Comparisons
Are radiologists exposed to dangerous levels of radiation?
I work as an Interventional Radiologist at a very large and well known hospital. Here any individual IR doc can do up to ~1000-1200 cases per year depending on how experienced they are. Generally speaking, radiation exposure is more about HOW you do the procedure versus how MANY you do. The geometry of the flouroscopy tube (radiation source), patient/table, and receptor can dramatically change the radiation exposure to the operator (as well as the patient). Positioning the tube and patient incorrectly can increase the exposure by up to 50x what is necessary to everyone in the room.
Generally speaking, well trained radiologists are aware of the implications of procedure and setup, and rarely do we ever run into trouble with personal radiation exposure. However, other fields of medicine who are not as well trained in the physics of radiation production (generally cardiologists) have a much higher incidence of radiation damage to patients and have much, much higher personal exposure levels.
Exposure limits are set by a federal organization called the Nuclear Regulatory Commission (NRC). NRC 10CFR20.1201 is the document that outlines exposure limits for people who work with radiation:
(i) The total effective dose equivalent being equal to 5 rems (0.05 Sv); or
(ii) The sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue other than the lens of the eye being equal to 50 rems (0.5 Sv).
(2) The annual limits to the lens of the eye, to the skin of the whole body, and to the skin of the extremities, which are:
(i) A lens dose equivalent of 15 rems (0.15 Sv), and
(ii) A shallow-dose equivalent of 50 rem (0.5 Sv) to the skin of the whole body or to the skin of any extremity.
The calculated full body effective dose cannot exceed 50 mSv in an annual setting, I have yet to hear of any of our doctors going over 10 mSv in a years period. Conversely it’s fairly routine for physicians from other specialties to be forced to stop performing procedures as their personal dose exceeds that 50 mSv limit.
In short, the risk of radiation exposure as a physician has much more to do with the quality of your work, rather than the quantity.
Radiation risk from medical imaging
Updated: January 29, 2020Published: October, 2010
There’s been a lot in the media about radiation exposure from medical imaging, and many of my patients are asking about it. They want to know if radiation from mammograms, bone density tests, computed tomography (CT) scans, and so forth will increase their risk of developing cancer. For most women, there’s very little risk from routine x-ray imaging such as mammography or dental x-rays. But many experts are concerned about an explosion in the use of higher radiation–dose tests, such as CT and nuclear imaging.
Over 80 million CT scans are performed in the United States each year, compared with just three million in 1980. There are good reasons for this trend. CT scanning and nuclear imaging have revolutionized diagnosis and treatment, almost eliminating the need for once-common exploratory surgeries and many other invasive and potentially risky procedures. The benefits of these tests, when they’re appropriate, far outweigh any radiation-associated cancer risks, and the risk from a single CT scan or nuclear imaging test is quite small. But are we courting future public health problems?
Exposure to ionizing radiation on the rise
The radiation you get from x-ray, CT, and nuclear imaging is ionizing radiation — high-energy wavelengths or particles that penetrate tissue to reveal the body’s internal organs and structures. Ionizing radiation can damage DNA, and although your cells repair most of the damage, they sometimes do the job imperfectly, leaving small areas of “misrepair.” The result is DNA mutations that may contribute to cancer years down the road.
We’re exposed to small doses of ionizing radiation from natural sources all the time — in particular, cosmic radiation, mainly from the sun, and radon, a radioactive gas that comes from the natural breakdown of uranium in soil, rock, water, and building materials. How much of this so-called background radiation you are exposed to depends on many factors, including altitude and home ventilation. But the average is 3 millisieverts (mSv) per year. (A millisievert is a measure of radiation exposure; see “Measuring radiation.”)
Exposure to ionizing radiation from natural or background sources hasn’t changed since about 1980, but Americans’ total per capita radiation exposure has nearly doubled, and experts believe the main reason is increased use of medical imaging. The proportion of total radiation exposure that comes from medical sources has grown from 15% in the early 1980s to 50% today. CT alone accounts for 24% of all radiation exposure in the United States, according to a report issued in March 2009 by the National Council on Radiation Protection and Measurements.
If you mention the measurement of radiation, many people will recall the classic Geiger counter with its crescendo of clicks. But Geiger counters detect only the intensity of radioactive emissions. Measuring their impact on human tissues and health is more difficult. That’s where the sievert (Sv) and millisievert (mSv) come in. These units, the ones most commonly used in comparing imaging procedures, take into account the biological effect of radiation, which varies with the type of radiation and the vulnerability of the affected body tissue. Taking these into account, millisieverts describe what’s called the “equivalent dose.”
Ionizing radiation and cancer risk
We’ve long known that children and teens who receive high doses of radiation to treat lymphoma or other cancers are more likely to develop additional cancers later in life. But we have no clinical trials to guide our thinking about cancer risk from medical radiation in healthy adults. Most of what we know about the risks of ionizing radiation comes from long-term studies of people who survived the 1945 atomic bomb blasts at Hiroshima and Nagasaki. These studies show a slightly but significantly increased risk of cancer in those exposed to the blasts, including a group of 25,000 Hiroshima survivors who received less than 50 mSv of radiation — an amount you might get from three or more CT scans. (See “Imaging procedures and their approximate effective radiation doses.”)
The atomic blast isn’t a perfect model for exposure to medical radiation, because the bomb released its radiation all at once, while the doses from medical imaging are smaller and spread over time. Still, most experts believe that can be almost as harmful as getting an equivalent dose all at once.
Higher radiation–dose imaging
Most of the increased exposure in the United States is due to CT scanning and nuclear imaging, which require larger radiation doses than traditional x-rays. A chest x-ray, for example, delivers 0.1 mSv, while a chest CT delivers 7 mSv (see the table) — 70 times as much. And that’s not counting the very common follow-up CT scans.
In a 2009 study from Brigham and Women’s Hospital in Boston, researchers estimated the potential risk of cancer from CT scans in 31,462 patients over 22 years. For the group as a whole, the increase in risk was slight — 0.7% above the overall lifetime risk of cancer in the United States, which is 42%. But for patients who had multiple CT scans, the increase in risk was higher, ranging from 2.7% to 12%. (In this group, 33% had received more than five CT scans; 5%, more than 22 scans; and 1%, more than 38.)
What to do
Unless you were exposed to high doses of radiation during cancer treatment in youth, any increase in your risk for cancer due to medical radiation appears to be slight. But we don’t really know for sure, since the effects of radiation damage typically take many years to appear, and the increase in high-dose imaging has occurred only since 1980.
So until we know more, you will want to keep your exposure to medical radiation as low as possible. You can do that in several ways, including these:
Discuss any high-dose diagnostic imaging with your clinician. If you need a CT or nuclear scan to treat or diagnose a medical condition, the benefits usually outweigh the risks. Still, if your clinician has ordered a CT, it’s reasonable to ask what difference the result will make in how your condition is managed; for example, will it save you an invasive procedure?
Keep track of your x-ray history. It won’t be completely accurate because different machines deliver different amounts of radiation, and because the dose you absorb depends on your size, your weight, and the part of the body targeted by the x-ray. But you and your clinician will get a ballpark estimate of your exposure.
Consider a lower-dose radiation test. If your clinician recommends a CT or nuclear medicine scan, ask if another technique would work, such as a lower-dose x-ray or a test that uses no radiation, such as ultrasound (which uses high-frequency sound waves) or MRI (which relies on magnetic energy). Neither ultrasound nor MRI appears to harm DNA or increase cancer risk.
Consider less-frequent testing. If you’re getting regular CT scans for a chronic condition, ask your clinician if it’s possible to increase the time between scans. And if you feel the CT scans aren’t helping, discuss whether you might take a different approach, such as lower-dose imaging or observation without imaging.
Don’t seek out scans. Don’t ask for a CT scan just because you want to feel assured that you’ve had a “thorough checkup.” CT scans rarely produce important findings in people without relevant symptoms. And there’s a chance the scan will find something incidental, spurring additional CT scans or x-rays that add to your radiation exposure.
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Even one straightforward change in a procedure protocol can lead to a noticeable reduction in dose. For instance, CT exams included an anteroposterior localizer image for many years. Morin explains that one side effect of this was the breast received the entrance dose instead of the exit dose, increasing the amount of radiation to the patient. Procedures were modified over time, and providers started implementing a posteroanterior projection, which led to a noticeable reduction in dose.
Quality control also is crucial, Morin adds. Equipment should be inspected before a patient enters the room, not while he or she is being scanned. “You don’t want to discover you have a detector that is unbalanced with your first patient,” he says. “You want to find out before you even start seeing patients.”
Because of the technologist’s proximity to both the equipment and the patient, his or her training also plays a key role. “The technologist is the finger of this whole imaging body,” Mahesh says. “My emphasis is getting the tech to understand the system he or she is operating.”
Mahesh notes that a properly trained technologist helps the entire department run smarter and more efficiently; the technologist should know each scanner inside and out.
The Joint Commission also has been effective at keeping radiation levels low, pushing radiologists forward in terms of specific training techniques and documentation. Regan cites requirement PI.02.01.01 EP 6—which says “incidents where radiation dose indices exceeded expected dose index range are reviewed and analyzed”—as one example of how Joint Commission rules have evolved over time. This update is also noteworthy, she adds, because it applies specifically to CT while many other requirements focus on fluoroscopy.
Regan appreciates how the Joint Commission inspects facilities to make sure these different requirements are being followed. “They don’t want you to just pull out your policy book and say, ‘We have that in place,’” she says. “They want to see the end result. They don’t want you to just give lip service to the concept.”
How Administrators Can Help
Administrators can make an impact on dose as well by doing everything in their power to ensure radiologists aren’t being asked to rely on old, outdated technology and being sure policies are followed.
Balter believes providers must consider the positive impact that bringing newer equipment into the fold can have on radiation dose and patient safety. The average age of advanced imaging equipment in many facilities is pushing 7 to 10 years, and some basic radiographic rooms have been unchanged for 20 to 25 years.
Balter compares it to owning an older cell phone vs. something brand new. A phone from several years ago will help you make calls, but you miss out on huge advances in technology that are common on newer models. The same holds true for imaging equipment, he says, especially when you look at what vendors have done in the last several years when it comes to reducing dose. “I’m not an administrator, but equipment replacement to exploit improving technology should be on the table,” Balter says.
Regan and Clark also believe administrator buy-in is vital. Clark says they are excited to share their message with administrators at AHRA 2017 in Anaheim, Calif., and she hopes their success at VCU Health will help other providers take that next step forward.
“Administrators are the ones who have their fingers on the budget and they can make things happen in their facilities,” Clark says. “Once they see that it can be done and how important the monitoring and lowering of patient dose is, we can be a benchmark for them developing similar programs in their own facilities.”
If administrators need additional assistance pushing their facilities to invest in lowering dose, they can always point to the potentially huge cost savings that could come as a result. Purchasing newer equipment and putting more resources toward updating protocols can help eliminate repeat imaging, which can be quite costly for providers. Consider a study from 2015 that documented how health information exchange (HIE) use can cut down on repeat imaging and save providers more than $32,000 each year (J Am Coll Radiol. 2015 Dec;12(12 Pt B):1364-70). Cutting down repeat imaging in other ways could potentially bring about similar savings.
When discussing the various ways radiologists are reducing dose, Morin warns that there is a point where it’s possible to take things too far and do harm to the patient.
“It’s important to realize it isn’t good enough to just decrease the amount of radiation, because if the image becomes so noisy that a competent interpretation can’t be rendered, then you haven’t done the patient any favors,” he says. “Something else will have to happen with that patient, either another test using ionized radiation or another test that may be more difficult or extensive.”
This possibility also worries Mahesh, who says he has watched over the last decade as awareness and concern over radiation safety have shifted from “the extreme left” all the way to “the extreme right.” He once wrote extensively about lowering dose, but Mahesh says he is now “trying to bring the pendulum back to the center point, emphasizing radiation dose optimization rather than dose reduction.”
“Some enthusiastic physicians have the right goals in mind and want to keep risk as low as possible, but they don’t understand the balancing point between image quality and dose,” he adds. “I’ve seen some images where the quality was quite low and the physicians are struggling to find the pathology. I don’t think that’s necessary.”
Based on their experience over the years, Regan and Clark aren’t as concerned about dose reduction going so far that images are noisy because the individuals interpreting the images still have the final word. “The radiologists are not going to let the quality go down,” Clark says.
Clark is confident radiation doses will continue to get lower and lower, and part of this success will be due to technology while the rest will be due to people and processes. “At some point in the future, we’ll all have a central repository of our images somewhere,” she says. “That would be phenomenal, because as a large trauma center, sometimes we get people who come in from a small hospital somewhere and they can’t get those images to us, so they have to have those images repeated.”
Morin agrees with Clark’s confident outlook and thinks the best is yet to come as far as lowering dose is concerned.
“This is a very interesting and exciting time, because we’re now seeing doses change in a very positive way for the patient,” Morin says. “We’re saving many, many lives by using CT scans appropriately and making diagnoses early when treatment is still an option.”
How to Learn More
These are just some of resources are available for radiologists, technologists, physicists, administrators and trainees looking for more information on how they can reduce radiation dose at their own facilities.
Busted: Three Common Myths About Radiologic Technology
Feb 7, 2019
- Career Tips & Advice
Radiology is a rewarding, yet sometimes misunderstood medical field. Although vaguely aware of the role radiologists and technologists play, many people fail to recognize just how quickly this field is growing. Concorde Career College’s radiologic technology program offers much-needed clarity regarding the responsibilities given to radiologic technicians. Prior to entering this exciting program, several students arrive burdened with the following misguided notions. Myth Radiologic technologists spend all of their time alone. Fact Radiologic technologists regularly interact with patients and other medical professionals. Radiologists and radiologic technologists are regarded by some as the anti-social introverts of the medical field. Although some radiologic technologists do prefer to keep to themselves, all have the opportunity to interact with others on a regular basis. The stereotype of the lonely radiologist or radiologic technologist sitting in a dark room is simply untrue. Radiologic technologists are given plenty of opportunities to interact directly with patients. They are responsible for positioning patients in a way that promotes accurate imaging. Many radiologic technologists specialize in oncology; these professionals may interact extensively with the same patients over a one to two-month period. Myth The job outlook for radiologic technologists looks grim. Fact Radiologic technology is a quickly-growing field. Employment opportunities in radiologic technology are better than ever, with the Bureau of Labor Statistics projecting an impressive 21 percent change in employment between 2012 and 2022 for radiologic and MRI technologists. This is significantly faster than the average projected job growth in other fields. The rapid projected growth in radiologic technology correlates with an expected rise in osteoporosis-related fractures, as well as other conditions associated with an aging Baby Boomer population. Earning potential for this field is just as promising as the job outlook; the current median pay for radiologic technologists is $55,910 per year. Myth The radiation associated with radiologic technologist positions is dangerous. Fact The health risks associated with radiologic technology are minimal. Many aspiring radiologic technologists worry that their field of choice may be dangerous, as it involves extensive work with diagnostic imaging equipment. Although those who worked in radiology prior to 1950 experienced a significantly increased risk of cancer, cardiovascular disease and other health problems, this is less of a problem for today’s radiologists and radiologic technologists. Research from the National Cancer Institute’s Division of Cancer Epidemiology and Genetics indicates that modern work in radiologic technology does not increase the risk of multiple myeloma, lymphoma, chronic lymphocytic leukemia, breast cancer or melanoma. Radiologic technology is an exciting, albeit misunderstood profession. Concorde aspires to bust the many lingering myths surrounding radiologic technology and inspire a new generation of technologists to make a difference. Join the growing population of radiologic technology students and get ready to launch a deeply rewarding career. Our career counselors can advise your today.
Does Low-Dose Radiation Pose a Threat to Radiologic Technologists?
On Mar 8, 2012 March 8, 2012
By Joyce Routson, HEALTHeCAREERS.com
Study shows no evidence that exposure to ionizing radiation in the workplace under proper controls causes more cancer
Bruce Alexander, PhD, is an epidemiologist and professor at the University of Minnesota School of Public Health and director of the U.S. Radiologic Technologist (USRT) Study. The 30-year old study, conducted by the University of Minnesota, the National Cancer Institute and the American Registry of Radiologic Technologists (ARRT), is the world’s-largest and most comprehensive study of people who are exposed to radiation in the workplace. The original goal of the study, which began in 1982 and has surveyed 146,000 U.S. radiologic technologists, was to determine whether repeated low-dose ionizing radiation exposure was related to cancer and other diseases.
Among other findings, the study showed that between 1983 and 1998, cancers in U.S. radiologic technologists were about the same as in the general population. Some cancer types, such as lung, rectum and oral cavity cancers, were significantly lower than expected in both male and female technologists. Some cancer types, such as breast cancer in women, and melanoma and thyroid cancer in both men and women, were slightly higher than expected. The study said that the elevated risks could be related to the occupation, or it could be because they work in medicine, R.T.s were able to have better access to healthcare and early detection.
What the study has not shown yet is why some people are more susceptible to cancer and why.
Information about the study is available at www.radtechstudy.nci.nih.gov.
Dr. Alexander talked about his work in a telephone interview.
Healthecareers: How long have you been the study director?
Bruce Alexander: Since the summer of 1999. This is a jointly run study with the National Cancer Institute but I became involved when the previous director, who started the study, left the university.
H: Can you explain what this study is about and what you are trying to find out?
BA: One of the things we know of all environmental exposure studies is that ionizing radiation can cause cancer. The question is, at what level. There is a lot of research about higher exposure in certain industries such as nuclear and in atomic bomb survivors, and in patients who get large doses in their medical care.
But there are not that many studies of people who receive exposure in the course of their work in the medical field, who get relatively low doses but protracted over many years. Also there are not that many studies where one of the populations is women; most radiologic technologists are women. We wanted to get a better understanding of any risk long-term, low-dose radiation can cause.
The other aspect of the study that has been ongoing and we hope to look at is the genetic aspect. We know that there is average risk across the population but people have different levels of susceptibility to radiation.
H: Are you looking at the impact on workers in radiology or the impact of radiation on the population as a whole?
BA: The main thing is the former. We are interested in the exposure characteristics of people who use it in their work. We will be collecting more information on personal medical exposure in this population. But by understanding in a population like radiology workers we can give reference points to those in other occupations. We can begin to understand any associations between exposure in the workplace and the potential health impacts, and how that’s related to exposure of a similar type out of the workplace.
We do see that radiation use in medicine is increasing and we see a lot more discussion and concerns about doses to patients. It’s used in CT scans, a lot of imaging, heart cathertization many cancer treatments.
H: Do radiologic technologists get more radiation than an average person does?
BA: Yes, radiologic technologists can get more radiation than the average person would but it depends on the type of work they do and what they did in the past. While it is possible for them to get more radiation exposure than the general population, there are controls and standards of protection that keep exposure low. Some types of work, for example nuclear medicine or interventional radiography, have the potential for more than those who do routine procedures. Those who perform routine procedures that are well-controlled get almost none.
Decades ago there could have been large exposures from poorly or unshielded X-ray machines. Now radiation is used in CT, diagnostic and therapeutic imaging as well as nuclear medicine. It is used under tight controls, but there is the potential of some exposure.
H: This study is many years old. What is the top finding so far?
BA: One of the most important findings is that for the overall population of R.T.s in general we’re not seeing a lot of excess morbidity. There is some evidence that past exposure associated with work did relate to an increased risk of breast cancer, skin cancer and cataracts. I’m talking in the earlier years of the profession.
We’re not seeing that as much in the most recent years. We are nearly completed with our exposure reconstruction project and we can then update our analyses with more complete data. Sometimes effects don’t show up for many years in people at risk for disease. Updating the analysis will determine if the effects we saw in the earlier workers is because they’ve had more time for the disease to occur.
Currently as we interpret the data, the study indicates current protection standards are appropriate. There is no evidence that working as a radiologic technologist at today’s exposure levels is leading to any excess in disease. There is not a lot of evidence with the current levels in the cohort that there is a relationship to increased risk of cancer. But we haven’t been looked at more specific exposures, the emerging technologies like nuclear imaging. We will try to integrate all sources of exposure. We want to ensure we are not missing something.
H: Regarding who is susceptible and who isn’t, what progress have you made on that front?
BA: Those are the most difficult types of studies to do. Progress is incremental when you look at the molecular biology of cancer. We’ve collaborated with large studies of breast cancer that look how small changes in DNA might be related. The human genome is complex – just finding a roadmap to it is like saying, ‘I have map of the U.S. and I know everything about it.’ We’re still in the beginning of this whole area of science – knowing how the environment and exposure like radiation interacts with the genome is a huge question.
H: The ARRT says that your study could contribute to understanding of whether vitamin D levels may or may not prevent cancer and other diseases. Does it?
BA: There has been some suggestion that vitamin D is related to the risk of cancer and survival. With this study population we have the opportunity to look at it a little bit . We ask about location and where they live and how much time is spent in the sun. Our bodies synthesize vitamin D from skin that is exposed to the sun’s ultraviolent light. We haven’t found anything yet, although there is some hint of association but not enough to get excited about. We had a sub-study that asked about specific questions and measured vitamin D in blood levels.
H: How long will the study run?
BA: We don’t have a firm end date. We plan on sending out a questionnaire to update our outcomes. Probably another 5-7 years.
I do want to say that this population has been outstanding in helping with the research. We’ve always had good response. They’ve been amazing.
H: What should radiologic technologists take away from this study?
BA: They should take away what they are trained to know. That they should know radiation is harmful and to keep exposures at the lowest level possible. There is no reason need to panic as long as they take precautions.
About the Author
Joyce Routson is a journalist on the Health eCareers News Beat Team who’s also written about healthcare, labor and recruiting for a number of publications including the Contra Costa Times, NurseWeek and Staffing Industry Report. A resident of the San Francisco Bay Area, she also works as an editor at Industry Intelligence Inc.
Studies of mortality among radiologists are important for evaluating radiation protection measures and understanding the long-term effects of protracted exposure to low level radiation. Previous U.S. studies have been limited by smaller data sets and reflect only earlier time periods. In the United States, the last follow-up of radiologists ended in 1975, leaving a large gap in understanding the risks today.
Study leader Amy Berrington de González, D.Phil., chief of the Radiation Epidemiology Branch at the National Cancer Institute (NCI), in Bethesda, Md., and her colleagues based the new study on records from the American Medical Association (AMA) Physician Masterfile, a database established in 1906 that has grown to include current and historical data for more than 1.4 million physicians, residents and medical students in the United States.
They compared cancer incidence and mortality rates between 43,763 radiologists and 64,990 psychiatrists who graduated from medical school between 1916 and 2006. Psychiatrists were chosen as a comparison group because they are unlikely to have had occupational radiation exposure.
“There’s been a big change in practice over the past few decades, with more doctors performing fluoroscopically-guided procedures, making it more and more difficult to find a physician comparison group that did not have exposure to radiation,” noted Martha Linet, M.D., study coauthor and senior investigator at the NCI Radiation Epidemiology Branch.
Overall, male radiologists who graduated after 1940 had a better health profile than that of their psychiatrist colleagues. The death rate for radiologists from all causes was lower and there was no evidence of increased mortality from radiation-related causes such as cancer or cardiovascular disease.
“Our most important finding is that radiologists have lower death rates from all causes of death combined, compared to psychiatrists, and had similar risks of cancer deaths overall,” Dr. Linet said.
In contrast, radiologists who graduated before 1940 faced increased death rates from certain conditions, including acute myeloid leukemia and myelodysplastic syndrome, which are known to be related to occupational radiation exposure. In these earliest workers, there were also increased death rates from melanoma and non-Hodgkin’s lymphoma.
The older radiologists also had a higher risk of cerebrovascular disease. Research in the last few years has found evidence that low to moderate doses of radiation may be associated with circulatory diseases and stroke.
The reduced health risks for more recent radiology graduates are likely due to developments and improvements in radiation protection and monitoring, according to the researchers, along with improvements in equipment safety.
“Most of the findings of increased risk were in the earlier radiologists,” Dr. Linet said. “We do feel there is evidence that decreases in dose in the United States and other countries seem to have paid off, reducing risks in recent graduates.”
Radiation Protection for Radiologic Technicians
Editor’s Note: This article has been updated for more recent advancements within the radiologic technician field. This article was originally published in February 2014.
Radiologic technicians (also called X-ray techs) prepare patients and equipment for imaging procedures, maintain patient records and help doctors examine the resulting images. If you are planning to become a radiologic technician, you may be concerned about exposure to radiation in the profession. Radiation is not an issue with technologies, such as MRI and ultrasound, which use magnetic fields and sound waves, instead of radiation, to generate images. X-ray and CT scans do pose radiation risks to both health care workers and patients. Many safety standards have been established for radiation protection for both of these groups. Here are some of the protective tips for safe radiation practice that you will learn in your education. During the coursework, you will also learn how to best protect the patient during imaging procedures.
X-ray rooms have barrier walls and windows that keep exposure inside the room. During these imaging procedures, radiologic technicians leave the room, or stand behind a protective shield, such as a curtain, that is designed to keep out radiation. In most circumstances, you will only be close to the equipment before the procedure (to set up the room and prepare the patient) and afterwards. There are a few exceptions, however, such as interventional radiology, during which radiologists and technicians may be present in the room to treat the patient using X-rays and other imaging techniques as guidance. Technicians also wear shielding devices, such as lead aprons, gloves, goggles and masks for radiation protection whenever necessary.
The government has established standards for exposure limits. Technicians wear badges that measure their exposure to radiation, and detailed records keep track of this in order to prevent it from exceeding the recommended lifetime limits. X-ray technicians observe the principle ALARA (as low as reasonably achievable). This principle states that radiation levels should always be as low as possible for a specific procedure. Simply keeping the levels under the recommended limits is not enough.
Female technicians should inform their employer if they think they are pregnant to avoid any risk to the baby. There is no consensus on whether a pregnant woman can continue working in radiation areas, but it depends on the circumstances. Some workers are exposed to very low levels and do not have to change their work responsibilities, but a pregnant employee should discuss the risks with her employer as soon as possible.
Learn more about how to become a radiology technician and the great career options that come from working in this important field. Find out about Fortis’ radiology technician programs today!
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Risks of Radiation
Weighing the Radiation Risks of CT, X-ray and Other Imaging
When X-ray radiation is absorbed within our bodies, it can damage molecular structures and potentially cause harm. Very high doses of radiation cause damage to human cells, as evidenced by skin burns, loss of hair, and increased incidence of cancer. Because high doses of radiation can cause cancer, it is therefore generally assumed that low doses may also cause cancer. However there is currently no direct scientific proof that this occurs, and some studies suggest that low radiation doses (such as those used in imaging) do not increase the risk of cancer .
At the present time all studies of the risk of cancer from low doses of radiation have limitations. Recent articles in the scientific literature predict thousands of new cancers caused by the use of CT and other radiation-based imaging, but those predictions are derived by multiplying the large number of imaging procedures in large populations by the small assumed risk of developing cancer associated with an imaging study. If one person has a CT scan (with a 10mSv dose) with a new cancer risk of one in 2,000, it does not mean that a second person having a CT scan will then double their risk to one in 1,000. Nor is it clear that if the same person has two CT scans, two weeks apart, that their risk will increase from one in 2,000 to one in 1,000. Among other published material on the subject, the Radiologic Society of North America and the American Association of Physicists in Medicine issued a well-respected position statement in 2011 that states:
“Risks of medical imaging at effective doses below 50 mSv for single procedures or 100 mSv for multiple procedures over short time periods are too low to be detectable and may be nonexistent. Predictions of hypothetical cancer incidence and deaths in patient populations exposed to such low doses are highly speculative and should be discouraged.”
- Mean Cancer Mortality Rates in Low Versus High Elevation Counties in Texas Dose Response. 2010; 8(4): 448–455.
- Radiation increased the longevity of British radiologists British Journal of Radiology (2002) 75, 637-639.
Risks of Radiation vs. Benefits of Radiation
Generally speaking, all medical procedures and tests carry both risks and benefits, and any consideration of radiation risk must be balanced against the benefits. Media reports generally focus on the risks of radiation, but there are substantial benefits to these tests that must be considered in any balanced discussion of risk versus benefit. After a radiation dose of 10 mSv (which is the kind of dose associated with many CT scans) the estimated risk of developing a fatal cancer is one in 2,000, but that risk must be considered in the context of the good that comes from receiving a dose of radiation. Undue anxiety about the cancer risks of radiation could potentially expose patients to far greater risks from delayed diagnosis or incorrect management.
Alternative Perspective Regarding Risk
Another way of thinking about risk is to focus on the likelihood that something will not happen, rather than the odds that it will happen. For example, a one in 2,000 risk of cancer means a 99.95 percent chance of not getting cancer.
Risks in Context
In addition to the benefits, the small risk from low-dose X-ray radiation should be considered in the context of other risks. The risk of death from smoking, for example, kills 440,000 Americans every year, a much greater and easily reversible proven death toll from a man-made product that produces no medical benefit.
To put the estimated risk of developing cancer from an imaging study in context, keep in mind that:
- The annual dose of radiation we all receive from background radiation is from 3 to 5 mSv.
- Flying from New York to Los Angeles two or three times is equivalent to receiving the dose of radiation from a chest X-ray.
- Spending nine to 50 days in Denver, Colorado is equivalent to receiving the dose of radiation from a mammogram.
The amount of radiation during a typical body CT scan (10 mSv) is about the same as the radiation we get every two years from background sources, and the presumed risk of getting a fatal cancer from this amount of radiation is about one in 2,000. The table and graph below put this risk in the context of other occurrences that are of similar magnitude. For example, a patient who never smoked is more than twice as likely to die from lung cancer as from a cancer caused by a typical CT scan.
Risk of Death from Common Occurrences
One of medicine’s most remarkable achievements is the use of X-rays to see inside the body without having a surgeon wield a scalpel.
Before medical X-ray machines were available, people who were in an accident and had serious injuries would often need exploratory surgery to find out what was wrong,” says CAPT Thomas Ohlhaber, U.S. Public Health Service, a physicist and deputy director of the Food and Drug Administration’s (FDA) Division of Mammography Quality and Radiation Programs.
“But today, if you’re brought to the emergency room with severe injuries, within a few minutes you can be X-rayed, often with a sophisticated computed tomography, or ‘CT,’ unit, have your injuries assessed, and be treated quickly before you progress to a much more serious state,” says Ohlhaber.
X-rays are used for much more than identifying injuries from accidents. They are used to screen for, diagnose, and treat various medical conditions. X-rays can be used on just about any part of the body—from the head down to the toes—to identify health problems ranging from a broken bone to pneumonia, heart disease, intestinal blockages, and kidney stones. And X-rays cannot only find cancerous tumors, but can often destroy them.
Along with their tremendous value, medical X-rays have a drawback: they expose people to radiation. FDA regulates radiation-emitting products including X-ray machines. But everyone has a critical role in reducing radiation while still getting the maximum benefit from X-ray exams.
What are X-rays?
X-rays are a form of electromagnetic radiation that can penetrate clothing, body tissue, and internal organs. An X-ray machine sends this radiation through the body. Some of the radiation emerges on the other side of the body, where it exposes film or is absorbed by a digital detector to create an image. And some of it is absorbed in body tissues. It is the radiation absorbed by the body that contributes to the “radiation dose” a patient gets.
Because of their effectiveness in the early detection and treatment of diseases, and their ready access in doctor’s offices, clinics, and hospitals, X-rays are used more today and on more people than in the past, according to the National Council on Radiation Protection and Measurements.
- In the early 1980s, medical X-rays made up about 11 percent of all the radiation exposure to the U.S. population. Current estimates attribute nearly 35 percent of all radiation exposure to medical X-rays. (Nuclear medicine procedures, which use radioactive material to create images of the body, account for about 12 percent of radiation exposure, and natural sources of radiation in the environment that we’re exposed to all the time make up approximately 50 percent.)
- Radiation dose per person from medical X-rays has increased almost 500 percent since 1982.
- Nearly half of all medical X-ray exposures today come from CT equipment, and radiation doses from CT are higher than other X-ray studies.
Source: National Council on Radiation Protection and Measurements
The risks of medical X-rays include
- a small increase in the chance of developing cancer later in life
- developing cataracts and skin burns following exposure to very high levels of radiation
The small risk of cancer depends on several factors:
- The lifetime risk of cancer increases as a person undergoes more X-ray exams and the accumulated radiation dose gets higher.
- The lifetime risk is higher for a person who received X-rays at a younger age than for someone who receives them at an older age.
- Women are at a somewhat higher lifetime risk than men for developing cancer from radiation after receiving the same exposures at the same ages.
The risk of cataracts and skin burns are mainly associated with repeated or prolonged interventional fluoroscopy procedures. These types of procedures show a continuous X-ray image on a monitor (an X-ray “movie”) to determine, for example, where to remove plaque from coronary arteries.
“The benefits of medical X-rays far outweigh their risks,” says CDR Sean Boyd, U.S. Public Health Service, an engineer and chief of FDA’s Diagnostic Devices Branch. “And everyone involved with medical X-rays can do their part to reduce radiation exposure—whether they’re a consumer or patient, doctor, physicist, radiologist, technologist, manufacturer, or installer.”
Steps for Consumers
Consumers have an important role in reducing radiation risks from medical X-rays. FDA recommends these steps:
Ask your health care professional how an X-ray will help. How will it help find out what’s wrong or determine your treatment? Ask if there are other procedures that might be lower risk but still allow a good assessment or treatment for your medical situation.
Don’t refuse an X-ray. If your health care professional explains why it is medically needed, then don’t refuse an X-ray. The risk of not having a needed X-ray is greater than the small risk from radiation.
Don’t insist on an X-ray. If your health care professional explains there is no need for an X-ray, then don’t demand one.
Tell the X-ray technologist in advance if you are, or might be, pregnant.
Ask if a protective shield can be used. If you or your children are getting an X-ray, ask whether a lead apron or other shield should be used.
Ask your dentist if he/she uses the faster (E or F) speed film for X-rays. It costs about the same as the conventional D speed film and offers similar benefits with a lower radiation dose. Using digital imaging detectors instead of film further reduces radiation dose.
Know your X-ray history. “Just as you may keep a list of your medications with you when visiting the doctor, keep a list of your imaging records, including dental X-rays,” says Ohlhaber. When an X-ray is taken, fill out the card with the date and type of exam, referring physician, and facility and address where the images are kept. Show the card to your health care professionals to avoid unnecessary duplication of X-rays of the same body part. Keep a record card for everyone in your family.
FDA works to reduce radiation doses to the public while preserving image quality for an accurate exam by
- establishing performance standards for radiation-emitting products, recommending good practices, and conducting educational activities with health professionals, scientists, industry, and consumers to encourage the safe use of medical X-rays and minimize unnecessary exposures
- working with professional groups and industry to develop international safety standards that build dose-reduction technologies into various procedures and types of radiological equipment
- working with states to help them annually inspect mammography facilities, test mammography equipment (X-ray machines to help detect breast cancer), and ensure that facilities adhere to the Mammography Quality Standards Act, which establishes standards for radiation dose, personnel, equipment, and image quality
- monitoring industry technological advances that reduce radiation doses. Equipment manufacturers have already incorporated several advances to decrease the dose in newer machines that perform CT, which is considered the gold standard for diagnosing many diseases but also contributes greatly to the collective radiation dose to the U.S. population.
- participating in “Image Gently,” a national initiative to educate parents and health care professionals about the special precautions required for children who get X-rays. (Children are more sensitive to medical X-ray radiation than adults.)
Medical X-rays: How Much Radiation Are You Getting?
This table shows the radiation dose of some common medical X-ray exams compared to the radiation people are exposed to from natural sources in the environment. For example, the radiation exposure from one chest X-ray equals the amount of radiation a person is exposed to from their natural surroundings in 10 days.
The unit of measurement for an effective radiation dose is the millisievert (mSv). The average person in the United States receives a dose of about 3 mSv per year from naturally occurring radiation.
Three types of X-ray procedures are listed:
- computed tomography (CT) generates a three-dimensional image of part of the body
- radiography generates a two-dimensional image
- mammography is radiography of the breast
For this procedure:
Comparable to natural background radiation for:
|Computed Tomography (CT)-Abdomen||
|Computed Tomography (CT)-Body||
|Radiography-Lower GI Tract||
|Radiography-Upper GI Tract||
Less than 1 day
|Computed Tomography (CT)-Chest||
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