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Radiation Safety

Radiation safety includes a basic understanding of ionizing radiation and its use in diagnostic medicine. Radiation safety may also require formal instruction regarding x-rays and radiation issues. Please direct your questions regarding specific protocols to the facility radiation safety officer (RSO).

Principles and Knowledge

X-rays are a form of radiant energy that enters matter (e.g., human tissue). Some X-rays will be absorbed by and interact with matter partially or completely, whereas others will pass through without interaction. When X-rays enter the body, denser tissues (such as teeth and bone) absorb more X-rays than softer tissue (such as muscles and digestive organs). As such, various body tissues may be affected more or less significantly by exposure, and associated risk of exposure may be affected, as well.

X-rays cannot be "focused" but do require collimation (restriction of X-ray beams) and filtration (removal of low-energy X-rays) to narrow the field of exposure. Tightly collimating the X-ray beam to the area of interest reduces the amount of scatter and the volume of tissue exposed, and it improves image quality.

The majority of the radiation dose received by the speech-language pathologist (SLP) or other study participants (provided that the primary beam is avoided) comes from scattered radiation. Scatter is a group of X-rays that interact with matter and change direction. As the X-ray beam interacts with the patient's tissue, radiation is scattered more or less uniformly in all directions. These X-rays may lose some of their energy but can still interact and be absorbed by other tissue.

It is the SLP's responsibility to perform all of the tasks described below.

  1. Become familiar with the roles and responsibilities of the medical facility, radiologist, radiology technologist, and facility RSO in conducting safe, effective videofluoroscopic swallowing studies (VFSSs) for patients (adults and pediatrics) and workers. In this task, the SLP
    • identifies the RSO in the facility;
    • identifies the appropriate personnel who can confirm that the fluoroscopic system meets all federal and state radiation standards; and
    • confirms, in conjunction with the radiologist, that the fluoroscopic system has collimators to limit the radiated field to only the oropharyngeal region, trachea, and esophagus.
  2. Identify the local agencies/organizations that have regulatory authority concerning ionizing radiation and the recommended radiation dose limits for workers and the general public. Relevant organizations may include the following:
    • Nuclear Regulatory Commission (NRC)
    • State Department of Health-Bureau of Radiation Protection
    • National Council on Radiation Protection (NCRP)
    • American College of Radiology (ACR)
  3. Apply knowledge of radiation safety through appropriate selection and referral recommendations for individuals to undergo videofluoroscopic procedures, and be cognizant of radiation exposure to individuals receiving VFSS relative to timing and frequency of follow-up studies.
  4. Apply knowledge of radiation safety through implementation of well-planned, efficient VFSSs that keep radiation exposure "as low as reasonably achievable" (ALARA) while conducting a thorough exam.
    • Practice therapeutic maneuvers, wherever possible, before fluoroscopy is used or during breaks in fluoroscopy.
    • Position the patient via the guiding beam light before fluoroscopy is engaged.
    • Use appropriate barium (contrast) viscosity ranges for swallowing.
    • Use appropriate barium quantities.
  5. Participate in annual radiation safety programs and radiation exposure monitoring offered by your medical facility and mandated by your state Department of Health's Bureau of Radiation Protection.
  6. Know and practice the fundamentals of dosimetry in the monitoring of radiation exposure.
    • Wear a film badge (called a dosimetry badge) on the outside of the lead apron at the neck area. This badge will be reviewed periodically by the RSO-some facilities may require additional badges to be worn at various locations on the body (e.g., exposure to the hand due to feeding patients).
  7. Integrate the cardinal radiation safety factors (detailed below).
    • Time: Whenever possible, reduce the duration of the study (halving time halves personal exposure) and rotate assignments between staff members.
    • Distance and Location: Remain as far from the patient and radiation equipment as practical-increasing distance is one of the most effective means of reducing exposure. The amount of radiation exposure that you receive is inversely related to the distance you are from the source (this is known as the inverse square law). Location relative to the radiation equipment may also influence exposure (i.e., next to, in front of, behind).
    • Shielding: During study, wear protective apparel-such as lead aprons, eye shields, thyroid shields, and lead gloves-to decrease radiation exposure to vulnerable body organs. The amount of exposure decreased by shielding will vary with the energy of the X-ray and the thickness of the shield.
      (Hayes et al., 2009)
  8. Know and practice special considerations and safety precautions given to individuals who are pregnant (radiation patients and workers).
    • If the SLP participating in the VFSS is pregnant, that SLP declares the pregnancy and contacts the facility RSO for personal radiation safety management issues (e.g., dose rates, extra protection, exclusion from conducting studies, any previous exposure history).
    • SLPs who are pregnant wear a lead wraparound apron of the highest lead content.
    • SLPs who are pregnant may require more frequent dosimetry badge review. An additional dosimetry badge is worn at the waist under the apron.
    • The first trimester is the time during which the embryo is most vulnerable to the potential biological effects of radiation. Normal protective measures typically keep the embryo/fetus of a pregnant worker well below dose limit (DL) recommendations.

References

American College of Radiology. (2017). ACR practice parameter for the performance of the Modified Barium Swallow. Retrieved from https://www.acr.org/-/media/ACR/Files/Practice-Parameters/modified-ba-swallow.pdf

Hayes, A., Alspaugh, J. M., Bartelt, D., Campion, M. B., Eng, J., Gayler, B. W.,...Rostkowski, M. (2009). Radiation safety for the speech-language pathologist. Dysphagia,24, 274-279.

Kelchner, L. (2004). Radiation safety during the videofluoroscopic swallow study: The adult exam. Perspectives on Swallowing and Swallowing Disorders (Dysphagia), 13, 24-28. doi:10.1044/sasd13.3.24. Retrieved from https://doi.org/10.1044/sasd13.3.24

U.S. Nuclear Regulatory Commission. (1998). Dose equivalent to an embryo/fetus. Retrieved from http://www.nrc.gov/reading-rm/doc-collections/cfr/part020/part020-1208.html

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