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Thread: Spinal CT scans/cancer risk

  1. #1
    Join Date
    Sep 2012
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    23

    Spinal CT scans/cancer risk

    Hello:

    Although there is research on how much radiation is received and/or the increased cancer rate from brain and abdominal CT scans, I can't seem to find any specifically on spinal CT scans and the cancer rate. Does anyone know of a link where I can read about this? I had a recent MRI, but the radiologist said he could not see my fusion from the MRI and that I would need a CT scan. (I have had all the hardware removed) Does anyone know, from their own personal experience, if a spinal surgeon can see fused discs on an MRI better than a radiologist? That is, has anyone seen a spinal surgeon and brought their MRI's and the spinal surgeon was able to use the MRI and you did not require a CT scan?

    Thanks for sharing if you have had experience of this!

  2. #2
    Join Date
    Jan 2008
    Location
    Oregon
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    1,160
    Hi there,

    MRI is best for viewing soft tissues, and CT is best for viewing bone. Fusion is bone, so you need CT to see it clearly.

    When I broke my rods a CT was needed to see if there was complete bony fusion or if there was a non-union (turned out to be the latter). An MRI would not have helped.

    With any CT or radiation exposure you always need to weigh the risk vs the benefit. You should have a CT only for a definite reason, to answer a question that will change treatment. If you are not having problems, a CT should not be done. You always have to weigh if the risk from the large radiation dose outweighs the benefit to be gained by obtaining the info the CT can provide. It is always best to avoid excessive radiation exposure, but sometimes it is necessary to answer questions about the spine when there is pain or other problems.

    BTW, just a small point here, but with a posterior fusion the discs aren't what is actually fused, it is bone on the back of the spine. In anterior fusions the discs are removed and fusion material is placed there, so the disc space will fuse over.

    I do not think a spine surgeon can see more fusion than a radiologist. I think they have equivalent skills, all things considered.
    Gayle, age 49
    Oct 2010 fusion T8-sacrum w/ pelvic fixation
    Feb 2012 lumbar revision for broken rods @ L2-3-4
    Sept 2015 major lumbar A/P revision for broken rods @ L5-S1


    mom of Leah, 15 y/o, Diagnosed '08 with 26* T JIS (age 6)
    5/10 VBS Dr Luhmann Shriners St Louis
    5/16 6 yrs post-op, 24*T/ 22* L, mild increase in curves, watching

    also mom of Torrey, 12 y/o son, 16* T, stable

  3. #3
    Join Date
    Sep 2012
    Posts
    23
    Hi:
    Thanks so much for answering me and for telling me that you yourself had needed a CT scan. I also appreciate the clarification about where the fusion actually is, that is very helpful.

    I'm still wanting to read some actual info on the radiation exposure of spinal CT scans. I've found webpages that list comparisons between say, abdominal scans and X rays, but cannot find any mentioning spinal scans. I'm also wondering if a plain old X ray would suffice.

    I spent my childhood having full spinal X rays twice a year for many years so radiation exposure for me is something I'm trying to be very careful about, especially since my other life circumstances have added to my risk of cancer.

    Anyone been to a spinal surgeon recently who was able to use just an MRI or an X ray? Let me know. BTW, what did they do before CT scans???

    Thanks!

  4. #4
    Join Date
    Jul 2008
    Location
    west midlands, UK
    Posts
    152
    Quote Originally Posted by Cornerthree View Post
    Hi:
    Thanks so much for answering me and for telling me that you yourself had needed a CT scan. I also appreciate the clarification about where the fusion actually is, that is very helpful.

    I'm still wanting to read some actual info on the radiation exposure of spinal CT scans. I've found webpages that list comparisons between say, abdominal scans and X rays, but cannot find any mentioning spinal scans. I'm also wondering if a plain old X ray would suffice.

    I spent my childhood having full spinal X rays twice a year for many years so radiation exposure for me is something I'm trying to be very careful about, especially since my other life circumstances have added to my risk of cancer.

    Anyone been to a spinal surgeon recently who was able to use just an MRI or an X ray? Let me know. BTW, what did they do before CT scans???

    Thanks!
    You could ask your surgeon about bone scans, I've been told its a reliable way to see fusion, I have recently had one to check for fusion.
    Fused T2-L4 with costoplasty on 3/11/10

  5. #5
    Join Date
    May 2010
    Location
    Indianapolis area
    Posts
    966
    X-rays can show indications of fusion, but likely will not be able to indicate whether fusion is complete.

    If you don't have any hardware, wouldn't you know if you have non-union? I.e. excrutiatng pain and/or limited mobility? Without hardware, I would think a nonunion would leave your spine unstable?

    Have you been to see a revision expert yet? I would think someone like Boachie or Lenke might be able to weigh in on your situation without requiring a CT. Maybe ask for a long-distance consult?

    Best,
    Evelyn
    age 44
    80* thoracolumbar; 40* thoracic
    Reduced to ~16* thoracolumbar; ~0* thoracic
    Surgery 3/14/12 with Dr. Lenke, T4 to S1 with pelvic fixation
    Not "confused" anymore, but don't know how to change my username.

  6. #6
    Join Date
    Sep 2003
    Location
    Northern California
    Posts
    6,795
    Evelyn...

    I agree... if there's a non-union and the implants have been removed, the spine should start curving significantly.

    --Linda
    Never argue with an idiot. They always drag you down to their level, and then they beat you with experience. --Dilbert
    I'm sarcastic... what's your super power? --Unknown
    ---------------------------------------------------------------------------------------------------------------------------------------------------
    Surgery 2/10/93 A/P fusion T4-L3
    Surgery 1/20/11 A/P fusion L2-sacrum w/pelvic fixation
    ---------------------------------------------------------------------------------------------------------------------------------------------------
    If you've signed up and are having trouble posting, please check your spam folder. An email was sent to the email address which you subscribed. You have to follow the instructions in that email. Done that and still having trouble posting? Contact Joe O'Brien at jpobrien@scoliosis.org.

  7. #7
    Join Date
    Sep 2012
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    Thank you for the replies. I was looking for specific information on spinal CT scans and cancer risks though, and also about what exactly can be seen on a CT scan. The comments about these things have been helpful to me.

  8. #8
    Join Date
    Jan 2008
    Location
    Oregon
    Posts
    1,160

    article about spine CT's and cancer risk

    Spine computed tomography doses and cancer induction.
    Richards PJ, George J, Metelko M, Brown M.
    Source
    X-ray Department, University Hospital of North Staffordshire NHS Trust, Staffordshire, United Kingdom. paula.richards@uhns.nhs.uk
    Abstract
    STUDY DESIGN:
    Computer modeling using patient computed tomography (CT) exposure data.
    OBJECTIVE:
    To adequately consent patients, radiation dose needs to be converted into a relative risk of inducing a cancer. This article estimates different radiation doses and their relative risk of inducing a cancer from spine CT.
    SUMMARY OF BACKGROUND DATA:
    There has been a marked increase in imaging, particularly CT, and medical exposures make up the majority of background radiation. There is little in the literature about radiation does form spine radiograph and CT imaging.
    METHOD:
    Based on Monte Carlo simulations and the use of software designed for CT dosimetry, the anatomic region of the spine was mapped onto a mathematical phantom. The routine CT protocol was applied with corrections made to reflect the variation in radiation exposure along the length of the spine, resulting from automatic exposure control. The effective dose was calculated for each protocol and the relative risk of cancer induction calculated.
    RESULTS:
    Risk ratio for inducing a cancer when CT scanning the whole lumbar spine was about 1 in 3200, which was much less than the risk of CTing the whole dorsal spine (about 1 in 1800) due to the longer coverage required and the anatomic implications of scanning in the region of the cervical dorsal junction. Quantitative CT of the lumbar spine is a low dose technique with estimated effective dose about 0.1 mSv with an estimated cancer risk of 1 in 200,000 compared to a typical chest radiograph estimated effective dose of 0.02 mSv, which gives a relative risk of causing cancer of about 1 in 1,000,000. Undertaking evaluation of the dorsal and lumbar markedly reduces the amount of radiation and therefore reduces the risk, for instance the estimated effective dose of CT from L3 to L5 is about 3.5 mSv, with an estimated cancer risk of 1 in 5200.
    CONCLUSION:
    Precise CT technique of the spine, covering the smallest area necessary to answer the clinical question, has a dramatic effect on the estimated cancer risk for individual patient. Cancer risks are summative, so spine CT imaging needs to be considered in the light of the total radiation risk to the patient over their lifetime.
    Gayle, age 49
    Oct 2010 fusion T8-sacrum w/ pelvic fixation
    Feb 2012 lumbar revision for broken rods @ L2-3-4
    Sept 2015 major lumbar A/P revision for broken rods @ L5-S1


    mom of Leah, 15 y/o, Diagnosed '08 with 26* T JIS (age 6)
    5/10 VBS Dr Luhmann Shriners St Louis
    5/16 6 yrs post-op, 24*T/ 22* L, mild increase in curves, watching

    also mom of Torrey, 12 y/o son, 16* T, stable

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