Preface
The goal of radiation safety is to minimize the exposure of ionizing radiation from fluoroscopy or x-ray. Although exposure to low levels of radiation does not cause immediate health effects, radiation exposure is cumulative and, over time, can increase the risk of cancer (United States Environmental Protection Agency [EPA], 2019; Lorenzo-Zuniga & Boix, 2011).
The length and intensity of exposure are affected by the type of radiographic equipment, the type of procedure, exposure parameters, and patient size. Patients with a higher body mass index (BMI) require a more intense beam of radiation, which increases the scatter of radiation to others in the vicinity (Le, Robinson, & Lewis, 2015). The safe use of radiation in the gastroenterology (GI) setting is guided by ALARA.
Radiation safety is a responsibility shared by the department of radiology, the radiation safety officer, and GI personnel.
Definitions
* ALARA is an acronym that stands for "As Low As Reasonably Achievable," which refers to the principle of keeping radiation exposure to a minimum.
* Body mass index (BMI) refers to the most commonly used measure for body fat. BMI is calculated by dividing a person's weight in kilograms by the square of his/her height in meters (kg/m2) (United States Department of Health & Human Services, 2010).
* Dosimeter is a personal radiation dose-measuring device.
* Ionizing radiation penetrates the human body, and the radiation energy can be absorbed in tissue. This has the potential to cause harmful effects to people, especially at high levels of exposure (Centers for Disease Control and Prevention [CDC], 2015).
* Radiation safety officer (RSO) is the person in a facility responsible for radiation safety. The RSO should be a person having knowledge and training in ionizing radiation measurement and evaluation of safety techniques and the ability to advise regarding radiation protection needs (EPA, 2014). It is the duty of the RSO to ensure that all licensed activities are carried out in compliance with the requirements of the license and the applicable rules and regulations.
General Principles of Radiation
A. Radiation Sources
Radiation exposure refers to "the amount of electrical charge produced by a mass of matter when x-rays are delivered to a specific point" (United States Food and Drug Administration, 2020). There are three types of radiation exposure:
1. Primary. The incident beam is the primary radiation source of radiation exposure for the patient. The primary radiation beam produced is focused and directed through the area to be examined (Shymko & Shymko, 1998).
2. Secondary. The personnel in the room are exposed to secondary radiation or scatter radiation (Wilson-Stewart, Shanahan, Fontanarosa, & Davidson, 2018). This is the major source of radiation to the GI personnel.
3. Leakage. Radiation from the radiographic machine itself (Campbell, Sparrow, Fortier, & Ponich, 2002).
B. Minimizing Radiation Exposure
All personnel must adhere to the elements of ALARA: time, distance, and shielding.
1. Time
* Minimize the time of radiation exposure.
2. Distance
* Positioning personnel as far away from the patient as possible is essential in limiting exposure (Lorenzo-Zuniga & Boix, 2011).
3. Shielding
* Lead skirting covering the operator side of the fluoroscopy table provides added protection and decreases scatter radiation from the patient (Meisinger, Stahl, Andre, Kinney, & Newton, 2016).
* Personal protective aprons containing lead shielding 0.5-mm thick can block more than 90% of scattered radiation. Wraparound lead aprons are useful when personnel turn away from the radiation source. The two-piece lead vests and aprons are recommended to decrease pressure on the lumbar and cervical disks, as well as delay muscle fatigue (Singla, Kwok, Gjorgi, & Young, 2018).
* Thyroid shields are recommended to decrease the risk of thyroid cancer.
* Eye protection is recommended to decrease the risk of radiation-induced cataracts (EPA, 2014). Optically clear lead glasses reduce eye exposure significantly.
Additional considerations may be necessary for various patient populations (e.g., pediatric, childbearing age, and pregnant) (Dumonceau et al., 2012). Refer to institutional policies.
C. Care and Maintenance of Shields
All leaded protective shields must be:
* Stored vertically and never folded. Cracks in the lead lining can develop at the fold, reducing the useful life of the shield.
* Evaluated for damage (tears, folds, and cracks) at least annually using visual and manual inspection. If a defect is suspected, fluoroscopic or radiographic inspection may be performed to confirm any defect before removing the item from service (EPA, 2014).
* Cleaned according to manufacturers' instructions for use.
D. Special Consideration of Pregnant Personnel
There are no mandatory requirements for pregnant personnel to avoid fluoroscopy. However, there are regulations that recommend careful monitoring and minimizing exposure to both the fetus and the mother (CDC, 2019; Dumonceau et al., 2012). A second dosimeter can be worn under the lead apron in pregnant personnel to help monitor fetal exposure, and dosimeters should be monitored monthly. Boom-mounted, table-mounted, or pole-mounted barriers can be used to minimize radiation scatter during fluoroscopy. Lead barriers that do not exert additional physical burden on pregnant personnel offer greater ergonomic benefit (Marx, 2017). Additionally, maternity-style lead aprons may be preferred by personnel.
Monitoring Personnel Radiation Exposure
A. A radiation exposure dosimeter is considered the gold standard for radiation surveillance (Christopoulos et al., 2016). It should be worn exterior to the lead shielding at the collar level. If a second dosimeter is worn, it should be worn at the waist level underneath the lead apron (Dumonceau et al., 2012).
B. The dosimeter should be removed and stored in a radioactive protective container or in the endoscopy area in a place that reduces exposure to matter (e.g., heat) that may alter the readings (Meisinger et al., 2016).
C. Dosimeter data are collected monthly to monitor exposure to radiation. It is the responsibility of the RSO to report unsafe limits of radiation exposure. Personnel assignments or reassignments may be based on the exposure reports.
Quality Improvement
The RSO should act as an advisor to a quality improvement program in the GI setting, as it applies to radiation safety.
Summary
To maintain radiation safety in the GI setting, all participating personnel are responsible for the proper set-up and use of radiologic equipment. There must be consistent application of the principles of ALARA and a conscious effort by all personnel to minimize radiation exposure throughout the procedure. All institutional policies regarding radiation use and safety must be followed.
The Society of Gastroenterology Nurses and Associates, Inc. recommends that each practice setting maintain and implement a radiation safety program that ensures the safety of the patients, as well as all personnel.
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