Hello All!
It's been quite some time since I've made a post but I really wanted to post a literature review (and research proposal) that I did during my second course of my master's degree ("Facilitating Inquiry"). This took quite some time over the semester to compose but is something that I find very interesting and I hope you do as well!
The concern for radiation safety increases alongside the growing frequency in which medical imaging scans are performed. According to Holmberg, Czarwinski & Mettler (2010), “Currently, medical uses of radiation constitute more than 99.9% of radiation exposure to the world’s population from man-made sources” (p. 6). These numbers are supported by the similar percentage of 98% quoted on the website of the World Health Organization (WHO) (n.d.) and statements made in Picano, Vano, Domenici, Bottai & Thierry-Chef (2012). The effects of over-exposure to radiation can adversely affect a person’s health, ranging from milder symptoms to more potentially fatal diseases (such as cancer and cardiovascular disease). These effects may develop quickly after exposure or later on in life and are dependent on the dosage and duration (United States Environmental Protection Agency, n.d.). Currently, there appears to be an overall lack of appropriate radiation safety knowledge by medical imaging professionals. This in turn, leads to poor adherence to clinical radiation safety protocols. Further investigation into radiation safety knowledge and practices of those working with radiation in a clinical setting and subsequently, their overall radiation exposure risk is needed. Therefore, the aim is to identify a potentially observable lack of adherence to established radiation safety procedures and standards in Canada, the consequences and the possible correlative or causative factors.
There have been previous studies conducted that have noted changes within the DNA structure, tissue damage and/or the development of health issues as a result of occupational radiation exposure. An increased risk of cardiovascular disease due to vascular changes has been identified in personnel working within an interventional radiology setting (Andreassi et al., 2015; Sun, AbAziz & Khairuddin Md Yusof, 2013). In the study conducted by Andreassi et al. (2015), they assessed the radiation exposure to 223 personnel in a cardiac catheterization laboratory located in Italy. They found that long-term exposure was found to accelerate vascular aging and there was a causal connection between occupational radiation exposure and early signs of subclinical atherosclerosis particularly to the left side of the participants’ body. The left side of the body was identified as the side closest to the radiation source which indicates a possible causative factor.
This study utilized a fairly large sample size and made use of genetic biomarkers to assess the radiation-induced changes. Additionally, in a study of 59 participants comprised of radiologists and cardiologists, the formation of cataracts in persons exposed to what is considered slightly lower amounts of radiation, i.e. lower than the established acceptable limits, was noted (Junk et al., 2004, as cited in Sun, AbAziz & Khairuddin Md Yusof, 2013). Carcinogenic effects of radiation are a great concern due to the potential development of various forms of cancer such as thyroid malignancies and an increased risk of brain cancer (Kesavachandran, Haamann & Nienhaus, 2012; Picano et al., 2012).
The ALARA Principle and Linear Non-Threshold Model
The ALARA Principle is a concept that is considered fundamental to radiation protection. It is an acronym that stands for “As Low As Reasonably Achievable” and is based on the common understanding that the use of “reasonable” methods such as time, distance and shielding can all be utilized to reduce radiation exposure. Time refers to the fact that less time spent around a radiation source equals less radiation exposure to the person. Distance is based on the inverse square law equation that increasing the distance between you and the radiation source reduces exposure by the square of the distance. Shielding utilizes personal protective equipment (PPE) and other non-wearable shielding options (normally made out of lead within the medical imaging field) that can reduce the radiation exposure received from the radiation source (California State University Fullerton, n.d.; Kesavachandran et al., 2012).
Figure 1. Models for the Health Risks from Exposure to Low Levels of Radiation. Canadian Nuclear Safety Commission. (2013). Linear-Non-Threshold Model. Retrieved from https://nuclearsafety.gc.ca/eng/resources/health/linear-non-threshold-model/index.cfm
Current Allowable Limits in Canada
It is understood that those professions that work within the medical radiation field are expected to receive higher radiation exposure rates than the general public. This has led to the establishment of limits to ensure that they are not over-exposed. In Canada, the radiation exposure limits have been set by the CNSC for nuclear energy workers (NEWs) and are as follows:
Figure 2. Stochastic and Deterministic Dose Limits for NEWs in Canada. British Columbia Institute of Technology. Nuclear Energy Worker Status [Image]. Retrieved from https://www.bcit.ca/files/safetyandsecurity/pdf/sas_52_nuclear_energy_worker_status.pdf
Despite the established dose limits, many departments have limits for their workers that are much lower, and this can lead to inconsistencies as to what is allowable depending on where you work. These inconsistencies also affect the radiation exposure received by patients (Bell, 2016). Regardless, NEWs are allowed to receive up to 50 times the radiation of the general public in one year. This is measured using personal radiation detection monitors that are submitted to the CNSC on a monthly or quarterly basis. Therefore, it is imperative that these workers, particularly in a healthcare setting, have adequate knowledge about these limits and use proper radiation protection in an effort to keep their exposure rates as low as possible.
Unfortunately, this inadequate level of understanding has been found in several studies and was identified in various professions including radiologists, technologists, residents, nurses and interns (Barbic, Barbic & Dankoff, 2015; Faggioni, Paolicchi, Bastiani, Guido, & Caramella, 2017, Kesavachandran et al., 2014; Ramanthan & Ryan, 2014; Szarmach et al., 2015).
In the article by Kesavachandran et al. (2012) published in the European Journal of Medical Research, they referred to a report that found that surgical trainees within an orthopaedic surgery setting were inadequately aware of ionizing radiation and radiation safety protocols. They also found that there was improper usage of fluoroscopic procedures by orthopaedic surgeons. This report further supports the idea that there is a lack of radiation safety knowledge and a non-adherence to radiation safety procedures within the orthopaedic surgery environment. However, this may not be generalizable to a medical imaging setting where the expectations of ionizing radiation and radiation safety knowledge is greater and as such, may reduce its external validity (Bhattacherjee, 2012 p. 36).
The use of radiation exposure detectors such as thermoluminescent dosimeters (TLDs) have become a useful tool in monitoring radiation exposure to NEWs. These monitors often measure radiation exposure received in a monthly or quarterly time frame. They do not protect from radiation but provide knowledge of radiation exposure which can influence radiation safety practices or promote changes to equipment and/or protocols. Duvall et al. (2013) conducted a study in New York, USA using 4 nuclear medicine technologists, 4 nurses, and 2 administrative employees. The employees were analyzed 12 months prior and for 12 months after selectively changing myocardial perfusion imaging procedures from rest/stress procedures to stress-only procedures. They also more frequently made use of high efficiency SPECT imaging in the second 12-month timeframe. The authors measured a 40% reduction in monthly recorded radiation doses across all staff members between both periods following these protocol and equipment changes.
The value of these detectors becomes apparent as further research is conducted on this topic. The use of TLD’s and other radiation monitors can be used to confirm the efficacy of current practices as well as be used to promote necessary changes within practice in an effort to reduce exposure (Sun, AbAziz & Khairuddin Md Yusof, 2013).
Providing radiation safety training has also been a recommendation in improving worker knowledge and adherence to radiation safety (Reeves & Mahmud, 2016). This ties into the concept that adequate knowledge on the part of those professionals working with ionizing radiation is extremely important and recognizes an observable lack of this. The use of departmental radiation safety training, radio-pharmacy training, time-out-protocol education and mandating annual radiation awareness/training programs are all ways in which this knowledge may be improved (Kearney & Denham, 2016; Kesavachandran et al., 2012; Sun, AbAziz & Khairuddin Md Yusof).
There still remains the need for further research into “safe” limits and providing this knowledge to those working with radiation (Dainiak, 2013. Overall, the research surrounding occupational radiation dose is limited and studies relating to sub-specialties such as interventional radiology, orthopaedic radiation and CT appears to be more dominant as compared to others, for example, bone densitometry and nuclear medicine.
The purpose of this study is to assess radiation safety knowledge and practices of workers within under-represented fields such as nuclear medicine. This will help to bridge the gaps of research relating to radiation safety found within the medical radiation field and help improve the knowledge surrounding occupational exposure. As a note of geographical interest, research conducted in medical radiation safety within or related to Canada has also been very limited and therefore, this research will create a greater understanding of the practices according to Canadian standards.
It's been quite some time since I've made a post but I really wanted to post a literature review (and research proposal) that I did during my second course of my master's degree ("Facilitating Inquiry"). This took quite some time over the semester to compose but is something that I find very interesting and I hope you do as well!
Assessing Adherence to Radiation Safety Protocols, Occupational Radiation Safety Knowledge and Exposure in a Canadian Medical Imaging Setting
Within the healthcare field, the medical imaging discipline has proven to be very beneficial in providing relatively non-invasive diagnostic information about patients’ health. This information can be used to diagnose or follow-up on a variety of medical conditions and may even be used in planning a treatment course of action. Though there are some imaging modalities that do not utilize radiation (i.e. MRI and ultrasound), x-rays, CT scans, mammography, bone densitometry, nuclear medicine studies and procedures done in interventional radiology all rely on the use of radiation. This use of radiation poses some unique hazards that may not be readily found in other areas of medicine. Potential over-exposure to radiation becomes an issue of patient safety as well as an occupational hazard to the operator/administrator.The concern for radiation safety increases alongside the growing frequency in which medical imaging scans are performed. According to Holmberg, Czarwinski & Mettler (2010), “Currently, medical uses of radiation constitute more than 99.9% of radiation exposure to the world’s population from man-made sources” (p. 6). These numbers are supported by the similar percentage of 98% quoted on the website of the World Health Organization (WHO) (n.d.) and statements made in Picano, Vano, Domenici, Bottai & Thierry-Chef (2012). The effects of over-exposure to radiation can adversely affect a person’s health, ranging from milder symptoms to more potentially fatal diseases (such as cancer and cardiovascular disease). These effects may develop quickly after exposure or later on in life and are dependent on the dosage and duration (United States Environmental Protection Agency, n.d.). Currently, there appears to be an overall lack of appropriate radiation safety knowledge by medical imaging professionals. This in turn, leads to poor adherence to clinical radiation safety protocols. Further investigation into radiation safety knowledge and practices of those working with radiation in a clinical setting and subsequently, their overall radiation exposure risk is needed. Therefore, the aim is to identify a potentially observable lack of adherence to established radiation safety procedures and standards in Canada, the consequences and the possible correlative or causative factors.
Radiation Over-Exposure and its Effects
In its initial discovery, radiation was mishandled and mismanaged which led to over-exposure that proved fatal to some, including early discoverers like Marie Curie and those working with Thomas Edison (Kiah & Stueve, 2012). If over-exposed, effects such as erythema, skin necrosis, hair loss, cataract formation, radiation burns, brain damage in foetuses and cancer may develop (Ploussi & Efstathopoulos, 2016; WHO, n.d.). The understanding of over-exposure to radiation has increased significantly over the last few decades, however as found in Kurtul & Kurtul (2018, pp.107), there remains an on-going issue with radiation safety knowledge and practices by these healthcare workers.There have been previous studies conducted that have noted changes within the DNA structure, tissue damage and/or the development of health issues as a result of occupational radiation exposure. An increased risk of cardiovascular disease due to vascular changes has been identified in personnel working within an interventional radiology setting (Andreassi et al., 2015; Sun, AbAziz & Khairuddin Md Yusof, 2013). In the study conducted by Andreassi et al. (2015), they assessed the radiation exposure to 223 personnel in a cardiac catheterization laboratory located in Italy. They found that long-term exposure was found to accelerate vascular aging and there was a causal connection between occupational radiation exposure and early signs of subclinical atherosclerosis particularly to the left side of the participants’ body. The left side of the body was identified as the side closest to the radiation source which indicates a possible causative factor.
This study utilized a fairly large sample size and made use of genetic biomarkers to assess the radiation-induced changes. Additionally, in a study of 59 participants comprised of radiologists and cardiologists, the formation of cataracts in persons exposed to what is considered slightly lower amounts of radiation, i.e. lower than the established acceptable limits, was noted (Junk et al., 2004, as cited in Sun, AbAziz & Khairuddin Md Yusof, 2013). Carcinogenic effects of radiation are a great concern due to the potential development of various forms of cancer such as thyroid malignancies and an increased risk of brain cancer (Kesavachandran, Haamann & Nienhaus, 2012; Picano et al., 2012).
The ALARA Principle and Linear Non-Threshold Model
The ALARA Principle is a concept that is considered fundamental to radiation protection. It is an acronym that stands for “As Low As Reasonably Achievable” and is based on the common understanding that the use of “reasonable” methods such as time, distance and shielding can all be utilized to reduce radiation exposure. Time refers to the fact that less time spent around a radiation source equals less radiation exposure to the person. Distance is based on the inverse square law equation that increasing the distance between you and the radiation source reduces exposure by the square of the distance. Shielding utilizes personal protective equipment (PPE) and other non-wearable shielding options (normally made out of lead within the medical imaging field) that can reduce the radiation exposure received from the radiation source (California State University Fullerton, n.d.; Kesavachandran et al., 2012).
Linear Non-Threshold Model
Currently, the linear non-threshold model is an international risk model used to set dose limits for radiation workers as well as the public. This model “conservatively assumes there is a direct relationship between radiation exposure and cancer rates.” (Canadian Nuclear Safety Commission (CNSC), 2013, p.1). However, at this time there is no definitive evidence that shows increased cancer risk in radiation exposures less than 100 mGray (a unit of absorbed radiation). (CNSC, 2013; Dainiak, 2013). This lack of evidence leads to a degree of uncertainty of carcinogenic risks in this range that requires further exploration.
Current Allowable Limits in Canada
It is understood that those professions that work within the medical radiation field are expected to receive higher radiation exposure rates than the general public. This has led to the establishment of limits to ensure that they are not over-exposed. In Canada, the radiation exposure limits have been set by the CNSC for nuclear energy workers (NEWs) and are as follows:
Figure 2. Stochastic and Deterministic Dose Limits for NEWs in Canada. British Columbia Institute of Technology. Nuclear Energy Worker Status [Image]. Retrieved from https://www.bcit.ca/files/safetyandsecurity/pdf/sas_52_nuclear_energy_worker_status.pdf
Despite the established dose limits, many departments have limits for their workers that are much lower, and this can lead to inconsistencies as to what is allowable depending on where you work. These inconsistencies also affect the radiation exposure received by patients (Bell, 2016). Regardless, NEWs are allowed to receive up to 50 times the radiation of the general public in one year. This is measured using personal radiation detection monitors that are submitted to the CNSC on a monthly or quarterly basis. Therefore, it is imperative that these workers, particularly in a healthcare setting, have adequate knowledge about these limits and use proper radiation protection in an effort to keep their exposure rates as low as possible.
Knowledge of Ionizing Radiation
The use of questionnaires and surveys are often conducted in order to assess the knowledge that these professionals have about ionizing radiation exposure and radiation safety. The level of knowledge about radiation often directly influences daily radiation safety practices. Along with directly measured effects noted in radiation operators and administrators, qualitative assessments of responses received in diagnostic imaging e.g. CT and fluoroscopy settings, have all found an inadequate level of understanding about radiation, its effects and radiation safety.Unfortunately, this inadequate level of understanding has been found in several studies and was identified in various professions including radiologists, technologists, residents, nurses and interns (Barbic, Barbic & Dankoff, 2015; Faggioni, Paolicchi, Bastiani, Guido, & Caramella, 2017, Kesavachandran et al., 2014; Ramanthan & Ryan, 2014; Szarmach et al., 2015).
In the article by Kesavachandran et al. (2012) published in the European Journal of Medical Research, they referred to a report that found that surgical trainees within an orthopaedic surgery setting were inadequately aware of ionizing radiation and radiation safety protocols. They also found that there was improper usage of fluoroscopic procedures by orthopaedic surgeons. This report further supports the idea that there is a lack of radiation safety knowledge and a non-adherence to radiation safety procedures within the orthopaedic surgery environment. However, this may not be generalizable to a medical imaging setting where the expectations of ionizing radiation and radiation safety knowledge is greater and as such, may reduce its external validity (Bhattacherjee, 2012 p. 36).
Reducing Occupational Radiation Exposure
The use of ALARA is important in reducing how much radiation is received by the worker. A common theme that arises from previously conducted research has determined that occupational radiation exposure is largely influenced by the actions of the operator/administrator themselves. The focus of many research topics has been the radiation exposure to patients, however, in reducing the patient radiation exposure dose, the radiation exposure to the operator/administrator is also reduced. This may be done by limiting the region of interest (ROI) to be imaged, lowering the voltage or milliamperage of the machine or by administering a lower radiopharmaceutical dose, while still ensuring quality images are obtained (Duvall et al., 2013; Heidbuchel et al., 2014; Sun, AbAziz & Khairuddin Md Yusof, 2013).The use of radiation exposure detectors such as thermoluminescent dosimeters (TLDs) have become a useful tool in monitoring radiation exposure to NEWs. These monitors often measure radiation exposure received in a monthly or quarterly time frame. They do not protect from radiation but provide knowledge of radiation exposure which can influence radiation safety practices or promote changes to equipment and/or protocols. Duvall et al. (2013) conducted a study in New York, USA using 4 nuclear medicine technologists, 4 nurses, and 2 administrative employees. The employees were analyzed 12 months prior and for 12 months after selectively changing myocardial perfusion imaging procedures from rest/stress procedures to stress-only procedures. They also more frequently made use of high efficiency SPECT imaging in the second 12-month timeframe. The authors measured a 40% reduction in monthly recorded radiation doses across all staff members between both periods following these protocol and equipment changes.
The value of these detectors becomes apparent as further research is conducted on this topic. The use of TLD’s and other radiation monitors can be used to confirm the efficacy of current practices as well as be used to promote necessary changes within practice in an effort to reduce exposure (Sun, AbAziz & Khairuddin Md Yusof, 2013).
Providing radiation safety training has also been a recommendation in improving worker knowledge and adherence to radiation safety (Reeves & Mahmud, 2016). This ties into the concept that adequate knowledge on the part of those professionals working with ionizing radiation is extremely important and recognizes an observable lack of this. The use of departmental radiation safety training, radio-pharmacy training, time-out-protocol education and mandating annual radiation awareness/training programs are all ways in which this knowledge may be improved (Kearney & Denham, 2016; Kesavachandran et al., 2012; Sun, AbAziz & Khairuddin Md Yusof).
There still remains the need for further research into “safe” limits and providing this knowledge to those working with radiation (Dainiak, 2013. Overall, the research surrounding occupational radiation dose is limited and studies relating to sub-specialties such as interventional radiology, orthopaedic radiation and CT appears to be more dominant as compared to others, for example, bone densitometry and nuclear medicine.
The purpose of this study is to assess radiation safety knowledge and practices of workers within under-represented fields such as nuclear medicine. This will help to bridge the gaps of research relating to radiation safety found within the medical radiation field and help improve the knowledge surrounding occupational exposure. As a note of geographical interest, research conducted in medical radiation safety within or related to Canada has also been very limited and therefore, this research will create a greater understanding of the practices according to Canadian standards.
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