Seeing Through Radiology Fear, Reality, and the Future
Brittany Siegel, SUNY Orange
Abstract: Diagnostic imaging, often used interchangeably with radiology, refers to all modalities of the field. These modalities include radiography (X-rays) , computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound. Revered for advances in medicine allowing doctors to diagnose internal medical conditions quickly and feared for its use of radiation, the field of radiology can be controversial. To determine whether the benefits outweigh the fears, the scope of the studies reviewed in this paper aim to test whether the benefits outweigh the negatives of radiology using several methods such as calculating rate of exposure compared to incidence of increased cancer occurrence, measuring the number of scans per patient annually, and assessing image quality with reduced radiation, amongst others. Overall, the majority of studies conclude that any potentially harmful effects are negligible when compared to the significance of radiologic findings. By providing research on medical, and quality care aspects while analyzing both positive and negative effects of these categories, this paper determines that the need for diagnostic imaging in the medical field outweighs its negative impacts.
Introduction
A Brief History of Radiology
Take a step back in time to Ancient Greece during a period when medicine often was based on nature and mystics, and less on evidence. In the 5th century, Hippocrates introduced the idea of rationalism to medicine. Rationalism used inductive reasoning: studying, tracking, and obtaining enough observations to narrow down diagnoses (Banerjee et al., 2012). This idea propelled into the 18th century, when the “concept of ‘social medicine’ appeared, and the idea of disease prevention was introduced” (Banerjee et al., 2012). During the 19th century, medicine boomed due to the Industrial Revolution. Discoveries in the science of cell division, color vision, and cellular theory allowed for a better understanding of the human body, as did the work of Louis Pasteur and Robert Koch on bacteriology. These provided huge steps forward. Another was taken with the invention of the stethoscope. Instruments to aid doctors in diagnoses started to become common. Phillip Bozzini created the first endoscope and was the first person to view the inside of the body (Banerjee et al., 2012). In 1895, the evolution of radiology began when Wilhelm Conrad Roentgen's discovered the X-ray (radiography). Using a ‘Crooke's tube’ which was an early version of the x-ray tube, he observed that the invisible rays were able to penetrate flesh to view interior part of the body such as bone (Bradley, 2008). X-rays broadened other forms of visualization including fluoroscopy, mammography, x-ray tomography, angiography, and positron emission tomography (PET). The 1970s introduced ultrasounds, magnetic resonance imaging (MRI), and computed tomography (CT) scans. More recently, the integrated use of these modalities allows for early diagnosis, reduced need for surgeries, and a lower rate of inpatient treatment. The value of radiology to the medical field can be seen clearly in its contributions to the advancement of patient care. As a quote from the International Day of Radiology conference suggests, “The last 100 years have seen many changes and the next 100 will be even more dramatic” (Banerjee et al., 2012).
Types of Radiology
Radiology enables doctors to visualize and diagnose internal medical problems so that they can move forward with treatment. The field of radiology uses ionizing and non-ionizing radiation to perform medical testing and procedures. Ionizing radiation “has enough energy per particle to rip electrons off of atoms and therefore break chemical bonds… but if the amount of ionizing radiation exposure is very low, our bodies can handle a few damaged molecules without any problem, so that there is no net harm done to our bodies” (Baird, 2015). Common modalities of radiology are radiography (X-rays), computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound. X-rays use ionizing radiation to take a ‘picture’ of the body to diagnose internal problems, such as tumors, fluid in the lungs, broken bones, and foreign objects. CT scans also use ionizing radiation to show “detailed images of internal organs, bones, soft tissue, and blood vessels. In emergency cases, it can reveal internal injuries and bleeding quickly enough to help save lives” (RadiologyInfo.org, 2019, Test/Treatment). MRIs and ultrasounds similarly show detailed images of organs and tissues in the body, but without the use of ionizing radiation. For this reason, ultrasounds are commonly used to monitor pregnancies.
Non-ionizing radiation is similar to radiation from microwaves and does not cause damage to molecules (Baird, 2015). Hazards linked to radiology primarily stem from ionizing radiation. An example of a hazard of ionizing radiation is nausea, which only occurs in the event of overexposure. One scan, even using ionizing radiation, is insufficient to cause issues. Overexposure, including multiple full body CT scans completed in short duration can lead to the radiation dose accumulating to a harmful level. This kind of situation generally is avoided through the diligence of radiology staff tracking the number of scans a patient receives annually.
Radiology is a key component of the medical field. Diagnostic imaging provides medical professionals with the insight they need to properly form diagnoses. However, the field is controversial because of associated risk factors. Opposing viewpoints hinge on whether the benefits outweigh the risks. Arguments can be made that radiology is simply not worth the risks. Some believe radiology contributes to cancer development and can decrease patient care. Despite arguments to the contrary, the benefits outweigh the negatives. When correct protocol and state, federal and international guidelines are followed, most of these risks can be avoided entirely. Risks existing outside of these parameters have the potential to be prevented. The field is in a period of transition regarding technological, educational, and training gaps with increased demand for care. Innovation, technological advancement, and implementation of new programs can aid in eliminating risks and bridges the gaps. This paper explores the negative impacts of radiology compared to the importance and necessity of diagnostic imaging by looking at the medical, and quality care aspects of radiology.
Medical Concerns of Radiology
Patients
Medical concern is at the forefront of discussion concerning impacts of radiology. Patient fear of radiology has been created, in part, from nuclear events as well as media and certain medical groups. Misunderstanding that all radiation is the same across the board contributes to patient concern. Most patients only know about radiation from what they have heard about nuclear events such as the bombing of Hiroshima and Nagasaki and the nuclear explosion at Chernobyl (Hendee & O’Connor, 2012). Ionizing radiation is emitted in these events, the same type found in x-rays and CT scans. Yet, the levels of radiation emitted in nuclear events far exceed those used in radiology.
Another driver of patient medical concern is the concept of radiation risks perpetuated by media and medical groups alike that radiologic procedures contribute to cancers and death. This premise is derived from the data in the Biological Effects of Ionizing Radiation (BEIR) report, a study that compiles data from four categories: those exposed to medical radiation, occupational radiation, environmental radiation, and specific environmental radiation exposure from former atomic bombing sites. The statistical data contained in this study contributes to patient fear, even though it contains inconsistencies that are often overlooked. A study for the Radiological Society of North America annual meeting using the BEIR report data, demonstrates that no evidence supports the claim of radiologic procedures contributing to cancers and death (Hendee & O’Connor, 2012). The sample determinations in the study are comprised of 100,000 patients, both male and female, with varied ages. The risk models used calculated Excess Absolute Risks (EARs) and Excess Relative Risk (ERR) to determine possibility of radiation induced cancer. Their values translate into a Lifetime Attributable Risk (LAR) to determine the possibility of radiation-induced cancer over the lifetime of an individual exposed to medical radiation. EAR “is the simple rate of disease among a population [and] has the units of the rates being compared” whereas ERR “is the ratio of the rate of disease among groups having some risk factor, such as radiation, divided by the rate among a group not having that factor” (National Research Council, 2006). The models are as follows, “ERR is the rate of disease in the exposed population divided by the rate of disease in an unexposed population minus 1.0, and the EAR is the rate of disease in an exposed population minus the rate of disease in an unexposed population” (Hendee & O’Connor, 2012). An association between exposure and disease can be made only if the EAR and ERR rates differ between the control and experimental groups.
Lifetime Attributable Risk (LAR), used to determine the possibility of radiation induced cancer over an individual’s lifetime, is based on calculated EAR and ERR values. If the LAR “provide(s) inconsistent results and no reason for the inconsistency is apparent, the data must be interpreted with caution. No general conclusion can be made that the exposure is a cause of the disease” (National Research Council, 2006). The BEIR study only looks at the LAR value, not the EARs or ERRs. However, the LAR, relies on EARs and ERRs which are unreliable sources. At times, the EARs under predicted ERRs and at others, it over predicted the ERRs and vice versa. For example, prostate cancer predictions had inconsistent values. The ERR model predicted 190 cancer occurrences, yet the EAR only predicted six (Hendee & O’Connor, 2012). This is unusual as both the EAR and ERR models are based on the same data. Any error value found between the two models should be far less than a difference between 190 and 6. For this reason, the metric derived from these inconsistent values is inaccurate. This discrepancy shows the error of one or both models. To combat this, the study committee attempted to fix the models, but did not succeed in doing so (Hendee & O’Connor, 2012).
The dosage amounts of radiation are measured in millisieverts (mSv), which is the annual radiation dose for a patient (Owlia, 2014). The dosages established by the International Atomic Energy Agency classified a low dose as less than 1mSv, an intermediate dose between 1-5 mSv, high doses between 5-20mSv, and excessive doses as more than 20mSv. As seen in Table 1, CT scans are an example of a high dose with a range of 10-15mSv.
In the BEIR study, when low dose radiation under 100 mSv was administered to the category of atomic bomb survivors and their offspring, it stimulated their immune systems and increased immune response, allowing them to ward off cancer cells. In contrast, patients outside of this group exposed to higher doses of radiation showed an increase in lung and breast cancer occurrence (Owlia, 2014). The United States Environmental Protection Agency refers to studies such as these, which show the link between increased likelihood of cancer and Lifetime Attributable Risk (LAR) of radiation exposure (US EPA, 2018). This increase can be considered an arguing point for why radiology is not worth the risk of cancer. However, at recommended dosages, it is difficult to differentiate between cancers caused by radiation and cancers caused by other factors. Limits and guidelines set forth by the EPA are based on the linear no-threshold hypothesis which states, “cancers caused by radiation cannot be differentiated from cancers that occur spontaneously in a population and hence cannot be identified as radiation induced” (Hendee & O’Connor, 2012).
Levels of radiation used in medical imaging vary depending on the organs being targeted. The term ‘effective dose’ refers to these levels (RadiologyInfo.org, 2019). The effective dose sets dosage limits but does not predict any kind of patient risk. Table 2 references examples of effective doses.
Misconstruing the term ‘effective dose’, in combination with the BEIR report, leads to some data being manipulated in an argument against radiology. For example, claims that radiation doses exceed the allowed annual exposure limit. Yet, limitations are found to the BEIR report, including the suspicious risk factor of 5% per 1 mSv, the assumption of age distribution as well as pre-existing illnesses reducing the possibility of radiation induced cancer due to shortened life expectancy. Virtually “all imaging procedures, including CT and nuclear medicine examinations, deliver doses to patients well below 100mSv when they are properly conducted” (Hendee & O’Connor, 2012). At an exposure rate of less than 100mSv, determining cancer and death predictions is not possible. Nonetheless, some media, medical groups, and government agencies highlight the BEIR study data to predict cancers and deaths, while overlooking the limitations of the study. Due to this limited view, patient fear of radiologic procedures is created. Evidence put forth in Frush & Perez 2017, demonstrates that much of the information available to the public is unbalanced and creates fear of harm. In regard to this point, concern is not justified.
Children
Conflicting viewpoints on the use of radiology practices in children can be a tricky topic. Arguments can be made that children particularly are at risk because of rapid cell division in children and fetuses which creates opportunity for cell damage from radiation (US EPA, 2018). Frush & Perez (2017) note, “the imaging care of children requires knowledge of appropriate pediatric techniques and attendant radiation exposure”. This argument claims that certain medical centers that do not specialize in pediatrics may not have radiology staff with appropriate expertise. It should be noted, however, that all proceduralists in the radiology department are required to complete training and clinical hours in a pediatric setting prior to certification from the American Board of Radiology. Therefore, even if they do not directly specialize in pediatrics, chances of being unable to correctly perform testing based on that alone is slim. A secondary source article published in Environmental Research reviewed an original research study completed at a pediatric hospital in Texas about the necessity of further pediatric radiology education. Researchers at the pediatric hospital between July 2011 and June 2012 found that,40% of all CT examinations did not have the correct number of evaluation steps (Kim, 2015, as cited in Frush & Perez, 2017, pg. 359). The number of evaluation steps are ordered by the physician; this means that 40% of children treated were not properly evaluated by their doctor. If a child is not evaluated accurately by a healthcare provider or attending doctor, radiologists cannot be expected to be held responsible. Improper evaluation can lead to misdiagnosis, which can lead to untreated conditions. Additionally, a misevaluation can affect radiation amounts, causing accidental overexposure. These factors contribute to the fear of radiology when used on children. However, this ties back to the root cause being incorrect initial evaluation. Most radiology employees follow strict regulations and protocols to protect “sensitive groups such as children, from increased cancer risks from accumulated radiation dose over a lifetime” (US EPA, 2018). Additionally, preventative measures are taken to safeguard against overexposure. For example, the As Low As Reasonably Achievable principle is applied. It limits the amount of time one can be exposed to radiation, increases the distance from the source, and uses shielding (CDC, 2015). This helps negate the medical concerns for children going for radiologic testing and procedures. Furthermore, the importance of radiologic testing of children is that it provides medical insight attributing to early detection. Negative impacts are outweighed when early detection allows more time for treatment and a less likely chance of further development of related conditions.
Allergic Reactions
As mentioned previously, radiologic testing can cause allergic reactions in some patients. Generally, allergic reactions are not identified until testing begins. The risk of allergic reaction is one source of patient concern. Specifically, Gadolinium-based contrast agents (GBCAs) are known to cause such reactions and are commonly used in MRIs to enhance images. The Food and Drug Administration (FDA) is involved in determining whether or not gadolinium is a cause for concern. “In September 2017 an FDA panel recommended adding a warning to gadolinium agents about gadolinium retention in certain organs, including the brain. Three months later, the FDA issued a warning requiring all GBCAs manufacturers to conduct further studies on the safety of these agents” (Bassett, 2019). A comparison study of PubMed and Google Scholar databases on GBCAs was completed by two New York radiology researchers in 2018 using the American College of Radiology classification system. They found allergic reactions caused by gadolinium are dependent upon the type being used. The differentiation lies between whether a GBCA is linear ionic or linear nonionic, macrocyclic or non-macrocyclic, and if it has protein binding or not (Behzadi, 2018). Allergic reactions were grouped based on severity range from mild to fatal. Mild allergic-like reactions included an itchy or “scratchy” throat, congestion, sneezing, pink eye, and runny nose. Moderate reactions included hives, skin inflammation, facial swelling, hoarseness of the throat, wheezing, and lung tightening without loss of oxygen. Severe reactions included risk of patient death potentially caused by facial swelling cutting off airflow, inflammation causing severe low blood pressure, throat swelling cutting off air flow, and anaphylactic shock (Behzadi, 2018).
Researchers used the Mantel-Haenszel type method of testing to determine the risk factor for allergic reaction using an error value of .05. The results show adverse allergic reactions greatly increased based on the “protein binding, macrocyclic structure, and ionicity [of the GCBAs]” (Behzadi, 2018). The Ionic linear protein binding GBCAs showed a higher occurrence of immediate allergic reactions whereas Linear non-protein binding GBCAs showed lower incidences of immediate reactions. This difference is due to the increased ionicity causing an increase in particles, as well as solution thickening in the bloodstream. Additionally, the low kinetic stability of GCBAs increases the risk of scar tissue buildup in the body leading to tissue death. The low kinetic stability also contributes gadolinium retention in the brain. Patients such as those with asthma who are at risk for allergic reactions are administered nonionic linear GBCAs for this reason (Behzadi, 2018). For the reasons addressed above, radiology departments have been moving away from the use of GBCAs. As a whole, when compared to the number of roughly 135 million radiologic tests annually (Smith-Bindman et al., 2019), the possibility of allergic reactions is low.
Adverse Reactions from Accidental Exposure
Although beneficial from a future health standpoint, not everyone reacts well to testing and risk for these patients does exist. When going for testing, patients need to be aware of possible adverse reactions of accidental over exposure radiation. These reactions can include nausea, vomiting or allergic reactions, such as rash or swelling (Behzadi, 2018). However, aside from allergic reaction, for symptoms of nausea and vomiting to occur, the “level of radiation would be like getting the radiation from 18,000 chest x-rays distributed over your entire body” (US EPA, 2018). Accidental radiation exposure is the cause of such reaction and is not only an issue in the United States. Reports from the Radiation and Nuclear Safety Authority compiled from all the radiology departments in Finland document the number of adverse reactions that occur from over exposure to radiation (Tarkiainen, 2020). An incident report is submitted whenever patients or medical staff are exposed to accidental or excessive radiation. This does not include small errors, such as patient movement or projection machine error. Additionally, not all incidents are reported due to lack of knowledge or time. Regulations in place validate the radiation of the patient, ensuring the benefits must outweigh any negative effects. However, a study conducted by research staff at the Oulu University Hospital in 2020 found that between 2010 and 2017, 312 adverse events occurred due to radiological imaging, with the majority stemming from computed tomography (CT). This study grouped incident reports into 5 categories: incorrect patient identification, unidentified pregnancy, equipment malfunction, human error, procedural error and site error (Tarkiainen et al., 2020). Reports from x-ray, computed tomography (CT), fluoroscopy, mammography and angiography, show CT reports account for the most incidents. The CT reports have the highest range from 1-20mSv (Tarkiainen et al., 2020). The data found in studies such as this, which look at the rates of accidental over exposure, provide the strongest evidence to suggest radiologic imaging is not worth the risk. Seventy-five percent of x-rays result in a low dose, less than 1mSV, of over exposure. The largest incident of excess radiation affected 14,000 patients who underwent chest x-rays with an improperly connected measuring chamber. During CT scans, researchers found 82% of adults were exposed to unnecessary radiation. Hospital personnel were the second largest group with 64% being exposed to unnecessary radiation. Examples of how this can occur include incorrect dose identification such as an abdomen CT being mistaken for a head CT, which calls for a higher dosage (Tarkiainen et al., 2020). Additionally, new hires sometimes press the button too soon, causing radiation exposure. Usually this is due to human error, although sometimes it can be tied back to training. While accidental radiation exposure does occur, aside from the small percentage of accidental exposure caused by simple human error, the other causes can be eliminated.
In summary, the entirety of medical concerns of radiology stem from the belief that medical radiation causes cancer and death. For now, after examination of patients, children, employees, allergic reactions, and adverse events, rates of cancer and death solely from radiology cannot be determined. From a medical standpoint, the evidence strongly suggests that the benefits of radiology outweigh any possible risks.
Quality of Care
Reduced Radiation and Image Quality
When discussing risks of radiation in radiology, the topic begs the question of why can’t the amount of radiation simply be reduced? The answer is: reducing radiation is possible. For the reasons discussed thus far, the quality-of-care patients receive is affected by the levels of radiation to which they are exposed. Reducing levels of radiation does not alter image quality or affect testing times, nor does it require any additional preventative measures (Zhang, 2020). It also benefits both patients and doctors alike. Radiation protection measures limit the amount of radiation exposure one has by using the aforementioned As Low As Reasonably Achievable principle (Zhang, 2020). Equipment used for this includes a lead apron, a thyroid blocker, and eye protection. Additional measures include adjusting the machine to lower settings. As long as the change is no more than 15%, the image quality is not affected (Zhang, 2020). Furthermore, two types of practices exist – Low Dose Imaging (LDP) and Ultra Low Dose Imaging (ULDP). Patients are not allowed to choose between the two: doctors do. In a double blinded randomized study conducted in 2020, to test whether reducing radiation levels affects image quality, both LDP and ULDP were used by varied proceduralists who were not told which they were using. If they felt the image quality was poor, they had the option to request the one they did not receive (Zhang, 2020). After the tests were completed, proceduralists completed a questionnaire regarding the quality of the images. Results showed no characteristic differences, no differences in the duration of tests, and no difference in image quality regardless of ULDP, the anatomical location of the test or the type of test. Additionally, no proceduralists requested a switch due to poor image quality (Zhang, 2020). Based on this information, using the ULDP protocol is the most beneficial way to ensure best patient care when performing radiologic tests and procedures. Using the ULDP protocol, no cause for worry exists regarding quality of care.
Reducing the Annual Radiation Exposure
Arguments for and against radiology believe creating awareness within the field about the risk of overuse is vital. Researchers at the University of Pittsburgh Medical Center conducted a study in 2014 reviewing radiation report findings for the Radiology Department between January and December 2011 (Owlia et al., 2014). Patients with more than three hospitals visits in a year received up to ten CT scans. The dosage amount for this number of scans equals roughly 90mSv. This amount only accounted for CT scans and it did not include any additional radiologic testing the patients may have had to undergo such as an X-ray or MRI (Owlia et al., 2014). These CT scans were conducted for the following categories: fall, fainting, confusion, altered status, seizure, trauma and neurological. Categories such as these require additional tests beyond CT scanning. Consequently, this leads to more radiation. The allotted amount of radiation per year for an individual is only 100mSv. Yearly amounts exceeding this dosage have been linked to increased cancer risks as discussed earlier. However, with that being said, these specific tests are not always necessary and safe methods are in place. Methods to reduce the number of scans performed include using the American Board of Radiology Appropriateness Criteria (Owlia et al., 2014). This encompasses identifying frequent patients exposed to repeat imaging. Its goal is “to eliminate redundant, inappropriate, and unnecessary imaging” (Owlia et al., 2014). Overall, in combination with following the American Board of Radiology Appropriateness Criteria and taking new steps to reduce unnecessary testing and overexposure, concern can be reduced.
Overuse of Computed Tomography Scans and Contrast Medias
Another concern is the overuse of computed tomography (CT) scans and contrast medias. Rarely is there a benefit to the patient and it creates a financial drain on budgets. An argument can be made that radiology departments are unperturbed about the burden overuse creates. Nonetheless, alternatives have been recommended to lessen the use of both CT and contrast medias.
CT scans, although vital for diagnosing certain medical issues, have become widely overused. As previously mentioned, CT scans account for the majority of negative effects of radiology. “In fact, CT in the United States now accounts for nearly 25% of the per capita radiation exposure per year. This is largely due to increase in medical imaging, rather than higher doses per procedure” (Frush, 2013). Despite this increase, the majority do not lead to “clinically significant findings” (Owlia, 2014). In roughly 43 years, not much has changed regarding the cost of the overuse of CT scans. According to a study from 1978, for individual hospitals completing 3,000 CT scans per year, the costs annually would be “$1.2 billion” (Abrams & McNeil, 1978). Owlia (2014) estimated that “5% of the country's gross national product” is spent on the roughly 70 million examinations completed annually in the United States.
As this remains an ongoing research topic, limits exist on what can be said about overuse of CT scans. Another element of radiology that can be considered unnecessary are contrast medias. Contrast medias are enhancers used in the radiology field to generate improved images (RadiologyInfo.org, 2019). They are also known as contrast materials or contrast agents. The contrast differentiates between a focal point of an organ, tissue or vessel and surrounding tissues in an image. They can be administered orally, intravenously or via enema. Specifically, “multi-detector computed tomography (MDCT) and magnetic resonances imaging (MRI) have been associated with [these materials]” (Nouh & El-Shazly, 2017). Contrast medias vary greatly and some reactions range from mild to life-threatening. Overall, the overuse of computed tomography scans and contrast medias both contribute to a drain of resources and finances as well as decreases the quality of care a patient receives without any indication of benefit. This is a negative impact, not outweighed easily, and a suggested solution is needed to resolve this ongoing issue.
Conclusion
Conclusion and Recommendations
The importance, necessity, and benefits of diagnostic imaging outweigh any miniscule negative impacts, or risks within the field. From a medical standpoint, concern over developing cancer from or having adverse reactions to radiation is counteracted with strict state, federal, and international regulations. According to Hendee & O’Connor (2012), at this time, the linear no-threshold hypothesis stands as accepted and that evidence does not support the idea of radiation-induced cancer. Furthermore, the annual dosage limit of 100 millisieverts is too low to differentiate between naturally occurring cancers and those believed to be linked to radiation. With the advancement of technology, the understanding and identification of cancer will improve, allowing a way to determine cancer and death risk levels for patients exposed to less than the annual limit. Fears of accidental exposure can be avoided by implementing annual approval testing, as well as performing installation and quality control tests of machinery (Tarkiainen et al., 2020). Additionally, avoiding the use of Gadolinium-based contrast agents will help circumvent allergic and adverse reactions.
The overuse of CT scans and contrast medias has negatively impacted radiology departments and patients. One suggestion made by the researchers at the University of Pittsburgh Medical Center to limit the overuse of CT scans and contrast medias is to keep an individual patient record of radiation amounts to not exceed the annual l00mSv. Another is to motivate doctors to put in extra effort in patient assessment before ordering. Being able to pre-assess pathology and symptoms predicting what a scan may reveal could avoid unnecessary overuse. The decrease in annual exposure levels would increase quality care.
After viewing the big picture of radiology, taking into account all the fears, concerns, truths, and benefits of it, imagine again a world without it. The numerous advantages of diagnostic imaging outweigh any negative effects it causes. It has changed the medical field for the better.
References
AboutCancer. (n.d.). Radiation imaging risks. Aboutcancer.com
http://www.aboutcancer.com/radiation_imaging_risks_0311.htm
Abrams, H., & McNeil, B. (1978). Computed tomography: cost and efficacy implications. American Journal of Roentgenology, 131(1), 81–87. DOI 10.2214/ajr.131.1.81
Baird, C. S. (2015). Is ionizing radiation always harmful? Science questions with surprising answers. https://wtamu.edu/~cbaird/sq/2015/01/05/is-ionizing-radiation-always-harmful/
Banerjee, A. K., Beckmann, E., Busch, U., Buzzi, A., & Thomas, A. (2012). Story of radiology. International Day of Radiology; ESR – European society of radiology. https://www.internationaldayofradiology.com/app/uploads/2017/09/IDOR_2012_Story-of-Radiology_RZ_lowres.pdf
Bassett, M. (2019, April 5). Thirty years later, questions remain on gadolinium-based contrast agent retention. RSNA. https://www.rsna.org/news/2019/april/gadolinium-based-contrast-agent-retention
Behzadi, A. H., Zhao, Y., Farooq, Z., & Prince, M. R. (2018). Immediate allergic reactions to gadolinium-based contrast agents: A systematic review and meta-analysis. Radiology, 286(2), 471–482. DOI 10.1148/radiol.2017162740
Bradley, W. G. (2008). History of medical imaging. Proceedings of the American Philosophical Society, 152(3), 349–361. http://www.jstor.org/stable/40541591?origin=JSTOR-pdf
Brenner, D. J., Shuryak, I., & Einstein, A. J. (2011). Impact of reduced patient life expectancy on potential cancer risks from radiologic imaging. Radiology, 261(1), 193–198.
DOI 10.1148/radiol.11102452
CDC. (2015, December 7). Radiation studies - CDC: ALARA. Centers for disease control and prevention. https://www.cdc.gov/nceh/radiation/alara.html
CDC. (2015, December 7). Radiation Studies Health effects of radiation. Centers for disease control and prevention. https://www.cdc.gov/nceh/radiation/health.html
Frush, D. P., & Perez, M. D. (2017). Children, medical radiation and the environment: An important dialogue. Environmental Research, 156, 358-363. DOI 10.1016/j.envres.2017.04.002
Frush, D. P. (2013). Radiation risks to children from medical imaging. Revista médica clínica las condes, 24(1), 15–20. DOI 10.1016/s0716-8640(13)70124-x
Hendee, W. R., & O’Connor, M. K. (2012). Radiation risks of medical imaging: Separating fact from fantasy. Radiology, 264(2), 312–321. DOI 10.1148/radiol.12112678
International commission on radiological protection. https://www.icrp.org/page.asp?id=10
National Research Council. (2006). Health risks from exposure to low levels of ionizing radiation b beir VII phase 2. The National Academies Press. https://www.nap.edu/read/11340/chapter/7
Nouh, M. R., & El-Shazly, M. A. (2017). Radiographic and magnetic resonances contrast agents: Essentials and tips for safe practices. World Journal of Radiology, 9(9), 339–349. Doi 10.4329/wjr.v9.i9.339
Occupational Safety and Health Administration, U. S. D. of L. (n.d.). Ionizing radiation - overview. www.osha.gov. https://www.osha.gov/ionizing-radiation
Owlia, M., Yu, L., Deible, C. (2014). Head CT scan overuse in frequently admitted medical patients. The American Journal of Medicine, 127(5), 406-410. DOI 10.1016 /j.amjmed.2014.01.023
RadiologyInfo.org. (2019). Contrast materials - What are contrast materials and how do they work? (n.d.). https://www.radiologyinfo.org/en/pdf/safety-contrast.pdf
Schieda, N., van der Pol, C. B., Walker, D., Tsampalieros, A. K., Maralani, P. J., Woo, S., & Davenport, M. S. (2020). Adverse events to the gadolinium-based contrast agent gadoxetic acid: systematic review and meta-analysis. Radiology, 200073. DOI 10.1148 /radiol.2020200073
Smith-Bindman, R., Kwan, M. L., Marlow, E. C., Theis, M. K., Bolch, W., Cheng, S. Y., Bowles, E. J. A., Duncan, J. R., Greenlee, R. T., Kushi, L. H., Pole, J. D., Rahm, A. K., Stout, N. K., Weinmann, S., & Miglioretti, D. L. (2019). Trends in Use of Medical Imaging in US Health Care Systems and in Ontario, Canada, 2000-2016. JAMA, 322(9), 843. https://doi.org/10.1001/jama.2019.11456
Tarkiainen, T., Haapea, M., & Liukkonen, E. (2020). Adverse events due to unnecessary radiation exposure in medical imaging reported in Finland. Radiography, 26(4). DOI 10.1016/j.radi.2020.02.002
US EPA,OAR,ORIA,RPD. (2018, September 17). Radiation health effects | US EPA. US EPA. https://www.epa.gov/radiation/radiation-health-effects
Walton, G. (2021, January). Eighteenth and nineteenth-century bonesetters’ tales. Unique Histories from the 18th and 19th Centuries. https://www.geriwalton.com/ eighteenth-and-nineteenth-century-bonesetters/
World-Nuclear.org. (2020, April). Nuclear radiation and health effects. https://www.world-nuclear.org/information-library/safety-and-security/radiation-and-health/nuclear-radiation-and-health-effects.aspx
Zhang, Z., Phang, C., Tan, R., (2020). Does reducing radiation levels for procedures affect image quality and radiation to proceduralists? A double-blinded randomised study of two protocols. Clinical Radiology. DOI 10.1016/j.crad.2020.09.003
댓글