Answer to Question #11089 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 had a lumbar spine x ray and was told that the dose was dependent upon my size/weight. Does this mean if I'm smaller I received more compared to a large person? Is this because the radiation isn't spread out as much?

A

Actually it is the other way around. Generally speaking, the larger the person, the higher the dose. To keep the amount of radiation striking the image receptor (e.g., x-ray film, digital receptor) at a level sufficient to produce a useful image, the output of the x-ray machine needs to be increased to compensate for more of the x rays being absorbed by the larger person.
 
Kent Lambert, CHP

Answer posted on 14 October 2014. 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.