Radiation Effective Doses to Adults Undergoing Modified Barium Swallow Studies

Abstract

Modified Barium Swallow Studies (MBSSs) are important tests to aid the diagnosis of swallowing impairment and guide treatment planning. Since MBSSs use ionizing radiation, it is important to understand the radiation exposure associated with the exam. This study reports the average radiation dose in routine clinical MBSSs, to aid the evidence-based decision-making of clinical providers and patients. We examined the MBSSs of 200 consecutive adult patients undergoing clinically indicated exams and used kilovoltage (kV) and Kerma Area Product to calculate the effective dose. While 100% of patients underwent the exam in the lateral projection, 72% were imaged in the upper posterior-anterior (PA) projection and approximately 25% were imaged in the middle and lower PA projection. Average kVs were 63 kV, 77 kV, 78.3 kV, and 94.3 kV, for the lateral, upper, middle, and lower PA projections, respectively. The average effective dose per exam was 0.32 ± 0.23 mSv. These results categorize a typical adult MBSS as a low dose examination. This value serves as a general estimate for adults undergoing MBSSs and can be used to compare other sources of radiation (environmental and medical) to help clinicians and patients assess the risks of conducting an MBSS. The distinction of MBSS as a low dose exam will assuage most clinician's fears, allowing them to utilize this tool to gather clinically significant information about swallow function. However, as an X-ray exam that uses ionizing radiation, the principles of ALARA and radiation safety must still be applied.

Keywords: Deglutition disorders; Fluoroscopy; Radiation.

Fig. 1.

Tube voltage (kV) distribution for the four projections. Also shown are the values for the median, standard deviation, tenth and ninetieth percentiles. Y-axis represents number of patients.

Fig. 2.

Kerma area product (Gy-cm²) distribution for the four projections. Also shown are the values for the average, standard deviation, and relevant percentiles. Y-axis represents number of patients.

Fig. 3

Effective dose (mSv) versus KAP (Gy-cm²) for the four projections. Also shown are the best-fit lines for a first order polynomial fit.

Fig. 4.

Effective dose (mSv) distribution for the four projections. Also shown are the values for the average, standard deviation, and relevant percentiles. Y-axis represents number of patients.