Answer to Question #10592 Submitted to "Ask the Experts"

Category: Medical and Dental Patient Issues — Diagnostic X Ray and CT

The following question was answered by an expert in the appropriate field:

Q
I recently had an esophagram and modified barium swallow. I would like to know what my effective dose is estimated to be from these exams. Are these values considered average for the procedures? What would be the compared values to having other x-ray exams or daily exposure?
 
Also, can frames be deleted from the study? If so, is the fluoroscopy time the actual time for all the images or only for the images printed?
 
Equipment was Digital Fluoroscopy
MBS fluoroscopy time: .23 seconds
Dose area product: 12:23
Entrance dose: .50
kVp: 73
 
Esophagram: fluoroscopy time 2.28 minutes/seconds
Dose area product: 601.85
Entrance dose: 27.60
Maximum kVp: 87.3
A

The answer to your last question regarding the frames of the study and fluoroscopy time is an easy one. The fluoroscopy time will be the accumulated time of fluoroscopy beam on time. Regardless of whether the facility printed (or archived) all images or not, that time will be an accurate reflection of total radiation exposure time from fluoroscopy. Also, the other parameter that will not change regardless of whether all images are printed or archived is the dose area product for the two phases of your examination.

I can say with certainty that the x-ray beam energies (kilovoltage peak or kVp) used in your study and the fluoroscopy times are consistent with modified barium swallow studies. I cannot assess your radiation dose from the entrance dose or dose area product information because these values must be verified by measurements and review of the images. Also, you did not provide the measurement units associated with these values. 

Swallow studies generally result in an effective dose of roughly 1 mSv, which is reported in the literature for these examinations (Brenner and Huda 2008).

Fluoroscopic studies such as esophagrams and swallow studies are very low-dose/low-risk procedures, where the little radiation exposure and resultant absorbed dose do not result in any risk when compared to the medical benefit of answering your physician's question concerning your health.

In accordance with current knowledge of radiation health risks, the Health Physics Society recommends against quantitative estimation of health risks below an individual dose of 50 millisievert (mSv) in one year or a lifetime dose of 100 mSv above that received from natural sources (PS010-2, Radiation Risk in Perspective). Doses from natural background radiation in the United States average about 3 mSv per year. A dose of 50 mSv will be accumulated in the first 17 years of life and 0.25 Sv in a lifetime of 80 years. Estimation of health risk associated with radiation doses that are of similar magnitude as those received from natural sources should be strictly qualitative and encompass a range of hypothetical health outcomes, including the possibility of no adverse health effects at such low levels.

I hope this helps you with your concern.

Jean A. Gresick-Schugsta, DABR

Reference
Brenner D, Huda W. Effective dose: A useful concept in diagnostic radiology. Radiation Protection Dosimetry 128(4):503–508; 2008. 

Answer posted on 17 April 2013. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.