Excess Radiation Exposure in Infants and Children From Videofluoroscopic Swallow Studies

The Modified Barium Swallow Study (MBSS) is the primary diagnostic test used to identify abnormalities in oropharyngeal swallowing function, detect the presence and etiology of aspiration, and test the effects of diet modifications and therapeutic interventions. While MBSSs are important diagnostic tests, they expose patients to ionizing radiation, which should be kept “as low as reasonably achievable” due to the associated cancer risks. Decreasing the pulse rate (pps) of the x-ray beam from 30pps to a lower pulse rate is a method of reducing radiation exposure that has become a widespread practice pattern despite the high likelihood that this compromises diagnostic accuracy, exposing patients to radiation and increasing cancer risks without providing useful diagnostic information. We found that, in adults, decreasing the pulse rate from 30 to 15pps significantly reduced diagnostic accuracy and changed treatment strategies. Reduction of diagnostic accuracy for children undergoing MBSSs is expected to be even more detrimental than in adults. A young child’s swallow occurs in about a third of the time of an adult swallow and is, therefore, visible in only a third of the images when compared to an adult swallow on MBSSs. When a reduced pulse rate of 15pps is used for a young child’s MBSS, the diagnostic accuracy would be less than that of an adult’s MBSS performed at 7.5pps, a rate that we know substantially decreases diagnostic accuracy in adults. Despite this expected reduction in diagnostic accuracy, approximately 47% of hospitals use pulse rates lower than 30pps to decrease children’s radiation dose. Clear evidence of the impact of reducing pulse rate below 30pps on diagnostic accuracy is needed to convince clinicians, speech-language pathologists and radiologists, to change their practice. Furthermore, radiation exposure and associated cancer risks to children during MBSSs are not well-understood. Our preliminary data and literature on radiation exposure and cancer risks in other medical imaging modalities indicate that young children have substantially higher cancer risks associated with radiation exposure in comparison to adults. However, we do not know the extent of cancer risks from MBSSs in children or how children’s radiation exposure and associated cancer risks are influenced by patient or fluoroscopy exam characteristics. This information is needed to guide clinician’s use of MBSSs in children, including the timing of and need for repeat MBSSs, and to facilitate accurate counseling of caregivers regarding the risks of the test. Once we know the radiation-related risks for children from MBSSs, we can evaluate whether the benefit of reducing radiation exposure by using pulse rates less than 30pps outweighs the risk associated with reduced diagnostic accuracy. Thus, the specific aims of this proposal are: Aim 1. Determine the impact of pulse rate on the assessment of swallowing impairment severity and treatment recommendations in bottle-fed children. Aim 2. Establish the standard radiation doses from MBSSs in children. Aim 3. Quantify patient cancer risks from MBSSs in children.