You are here:

Radiology/Lumbar spine/SI joint xray


QUESTION: I had an x-ray of my Lumbar spine and SI joints. These were done with digital x-rays at a local hospital. I'm trying to determine an approximate radiation dose I received. I'm a 35 year old female and weigh 50 kg and am 60 inches tall. Thank you

ANSWER: Katherine,
The dose received is less than flying on an airplane across the country.  However, site has many useful information for all kinds of exams to include doses.  It is a pretty interesting site and you can find out more about radiation exposure.

Hope this is helpful.


[an error occurred while processing this directive]---------- FOLLOW-UP ----------

QUESTION: I appreciate your timely response. Thank you. I did check out their website and it indicated that the dose is 1.5 mSv. Which is almost as much as a head CT. It seemed quite high for a plain film x ray. I was also told that the dosage is dependent on body weight. I'm 50 kg, does this mean I received a larger dose?
How do the xray machines even know how big a person is?


It may seems high relative to CT head but it is because of a lot of progress in CT technology which can now scan a head with only 2 mSv.  Dosage is dependent on weight and varies but not that much (unless you compare a baby with a 300lb person).  Radiology technologists are trained in dialing in an appropriate xray exposure to penetrate a given body.  There are guidelines and certainly experience that they use to produce a xray of a diagnostic quality. So the dose is more often chosen by a technologist and not the xray machine.  Now, CT is a totally different animal, and this is where a lot of progress has been made to dramatically reduce the dose.  Current modern CT machines figure out dose in microseconds as the bean penetrates the body and is captured by a detector on the other side. We now have a lot of modulation and different software that takes an low exposure CT xray and converts it into a diagnostic image of superb quality.



All Answers

Answers by Expert:

Ask Experts


Michael K.


Almost any kind of questions regarding any types of radiology exams, procedures, meaning of radiology reports etc...


12 year experience in the field of radiology

American Society of Neuroradiology, Senior Member Society of Pediatric Radiology, Active Member

Radiology Seminars in pediatric neurology American Journal of Roentgenology American Journal of Neuroradiology

Board Certified in Diagnostic Radiology Additional Certificate of Qualification in Neuroradiology

©2017 All rights reserved.

[an error occurred while processing this directive]