View Full Version : radiation exposure

9th June 2006, 11:32 AM
Thought this was quiet interesting, specially as it quantifies the difference in radiation exposure between conventional and digital imaging

Prospective randomized comparison of radiation exposure from full spine radiographs obtained in three different techniques
Torsten Kluba1 , Jürgen Schäfer2, Tobias Hahnfeldt1 and Thomas Niemeyer1

(1) University Tübingen, Department of Orthopaedics, Tübingen, Germany
(2) University Tübingen, Department of Radiology, Tübingen, Germany
(3) , ,

Received: 15 February 2005 Revised: 18 May 2005 Accepted: 8 July 2005 Published online: 22 April 2006

Abstract Problem: The purpose of the investigation was a comparison of two different digital X-ray techniques with conventional standing full spine films. Evaluation of dose area product, image quality and inter-observer error of Cobb-angle measurement in patients with scoliosis and kyphoscoliosis were studied.
Methods: A consecutive series of 150 patients were prospectively randomized into three groups. Patients in group 1 (n=53) received a conventional standing postero-anterior full spine radiograph. All films were evaluated on the light box. Patients in group 2 (n=48) received a X-ray using the digital storage phosphor plate system (CR). For group 3 (n=49) digital pulsed fluoroscopy was used. In groups 2 and 3 images were exported to a picture archiving and communicating system (PACS) workstation and viewed on a monitor (Siemens SMM 21140P, Germany). Dose area product measurements were performed in all three groups (Diamentor-M, PTW, Freiburg). Three experienced investigators independently reviewed all pictures. Pedicles and endplates were counted. Cobb-angles of the main curves were measured.

Results: The mean dose area product was 97.0 cGy cm⊃ (37.0–380.0 cGy cm⊃ for conventional films, 31.5 cGy cm⊃ (6.0–66.0 cGy cm⊃ for CR imaging and 5.0 cGy cm⊃ (1.0–29.0 cGy cm⊃ for digital fluoroscopy.

The differences of Cobb-angle measurements were not significantly different for the three methods. Differences in the count of pedicles and endplates between the investigators were significantly lower for the conventional film as an indicator for the best detail presentation.

Conclusion: A significant reduction in dose area product is possible with modern digital X-ray methods. The inter-observer error of Cobb-angle measurement is not significantly altered. The detail information is decreased in comparison to conventional films.

10th June 2006, 12:23 AM
Thats quite interesting Gerbo - thanks! I never really think about radiation when getting x-rays....I must have had a ton already!
I do know that in the hospital I had surgery in I had digital x-rays done...and in the hospital I go to for the scoliosis outpatients clinic they do the full on conventional x-rays....

I don't really understand the figures above but digital x-rays really have a lot less radiation....! wow!

Does anyone know if there is like a specific figure for the amount of x-rays any one person should have in order for them not to be harmed by the radiation??

10th June 2006, 08:50 PM
there is debate about the numbers, abbi. nobody really knows but you can use some of our members on here as a bench mark: people like sins and toni have over 100 xrays and counting, and many of those were taken in the bad old days when radiation was much higher than it is now. as we know, both of them continue in good health from a radiation exposure perspective.

the way i see it, if you need an xray, you need an xray. the consequences of not having xrays (either insufficient diagnosis or your surgeon going into theatre uninformed) are worse than exposure to a little radiation (in my opinion). there's also a lot of natural radiation in the world anyways, plus gadgets like microwaves and mobile phones emit them, so it's impossible to avoid, we can just limit our exposure in some scenarios.

10th June 2006, 11:31 PM
Becky's right; I used to have a sheaf of x-rays taken every time I had a cast change or new brace as a child. So that's ten years of having a x-rays taken on average 4 times a year, as a child, from 1976 to 1986. Then I had them taken every 6 months for the next 8 years at outpatient check-ups, then another bunch taken for my surgery at 18, and then another lot for the costoplasty when I was 26, and some taken after I fell down the stairs at a friend's house/slipped over on spilled water in Sainsbury's. I've also had MRI scans done 3 times, and bone scans done four times.

And the effects of radiation don't worry me in the slightest :D

12th June 2006, 03:27 AM
A little while ago when I was reading up on x-rays, I came across something about genetics and the way people react to x-rays and pretty much everything else....i.e., smoking etc. Some people are genetically more sensitive to radiation exposure than others. As for safe levels, I read there is no such thing as a safe level. :-o

12th June 2006, 09:09 AM
Originally posted by Abbi@Jun 9 2006, 11:23 PM
Does anyone know if there is like a specific figure for the amount of x-rays any one person should have in order for them not to be harmed by the radiation??
following links give some information about balance between background radiation and radiation through xrays. However, totally agree with Becky re balance of benefit and risk, i.e., despite some risks of having the x-ray, the risk of not having the xray can be much higher.







23rd July 2006, 08:24 PM
A lot of people ask me about that actually, when they find out about my back. But I've never worried about it. I needed those x-rays. Yes, they have radiation, but I'm exposed to radiation walking home from school or flying to Vancouver...

Do MRIs emit radiation? I thought they worked on magents....

24th July 2006, 02:47 AM
Originally posted by Joy@Jul 23 2006, 07:24 PM
Do MRIs emit radiation? I thought they worked on magents....
MRI scanning involves a very strong magnetic field, yeah, and pulses of radio waves. As far as we can tell, neither magnetic fields or radio frequency electromagnetic radiation poses any danger to tissue at all.

CT, though, does involve X-rays, although modern machines use less and less.

It's significant that X-rays are electromagnetic radiation, like light and radio waves, and have nothing to do with ionising radiation, which comes from radioactive decay. However, of course, some scans (such as PET) do involve ionising radiation, although I don't think they have any relevance to scoliosis.