Answer to Question #4262 Submitted to "Ask the Experts"

Can anyone clarify the difference in the total dose ranges in mrem between a barium swallow and a "modified barium swallow" that involves videotaping the swallows? How are the skill and competence of the technician and speech therapist dependent in doing the modified swallow?

A barium swallow involves the patient drinking both thin and thick barium along with gas-producing crystals, and sometimes a barium capsule. Average fluoroscopy times for this procedure are typically three to four minutes. A small portion of the swallowing action is recorded with digital or film CINE to make a motion picture of the swallowing. A modified barium swallow, also called a "rehab" swallow, involves the patient eating and swallowing pieces of food mixed with barium. The food begins with a thin consistency using something like applesauce and progresses to a thicker consistency with something such as meat. The study is over when the patient completes all foods with no problems or when aspiration occurs. This study is performed using digital or film CINE to record the swallowing process. Times can vary depending on patient condition but the average time is three to four minutes. For a digital CINE unit, we measured 1 R/min fluoroscopy exposure for the barium swallow and 0.26 R/min CINE exposure for the modified barium swallow. This difference could change somewhat if film rather than digital imaging is used, but the exposure received for the modified swallow would probably be no more than the exposure for the regular swallow.

Kenneth L. Miller, CHP, CMHP

Editor's Note: The exposure information in the answer is given in roentgen/hour (R/hr) rather than a total dose. The exposure rate is used to measure the output from diagnostic x-ray units. Generally, the changes in dose and dose rate will follow changes in the exposure and exposure rate. Thus, the dose for either the barium swallow or the "modified barium swallow" will be approximately 150 mrem as shown in Table 2, "Effective doses for complete x-ray procedures." Obviously, the skills of the staff are important factors in any medical procedure.