Too much radiation?

When I was a baby, probably about a year old, I had a CT scan, or an x-ray (can't remember which one) of my head. Then, last year, I had a CT scan done of my head again on 5/31/07. They found a 2 ml lipoma (fatty tissue). They didn't think much of it, so on 6/18/07, I had an MRI done on my head. I know MRI's don't use radiation or anything, but still. Anyway, if you read some of my other questions, you'll see my list of symptoms I've been having. I started getting heartburn, headaches, and tingling sensations before the CT scan, But all the other symptoms came after the MRI's and CT scans. Anyway, I got diagnosed with ehlers danlos syndrome, but I've been having some other issues, so my doctor wants me to have another MRI of my brain and spine. She also wants me to have an x-ray of my cervical, thoracic, and lumbar spine. I told her I already had a CT scan and an MRI done, but she didn't seem worried about me having more x-rays done. She also thinks I should have a gastric emptying scan done (since I've gotten eggy burps, vomiting episodes, and dizzy spells since I was little).  My GI doctor thinks I should also have an endoscopy and a colonoscopy done. Please tell me, do you think having all those x-rays and stuff (minus the endo and the colon and the MRI) could put me in any danger of developing cancer? Has there ever been a documented case of anyone catching diseases like HIV or hepatitis from unsterilized tools used for an endoscopy and a colonoscopy? I remember after I had the CT done, for about a week, one part of my scalp burned/hurt whenever I touched it. Please tell me what you think the risks are for having 2 head tests last year, and now having 2 more head tests plus an x-ray of my spine. Thank you!

[Fernando Roque, MD]

Hi.  Having frequent CT scans can place an individual at an increased risk for developing cancer.  Some doctors estimate that an exposure to radiation equivalent to 50 millisieverts (mSv) or more can already increase the risk for developing cancer.  Chest CT scans typically deliver doses between 6 - 15 mSv, while a head CT exposes the patient to 1.5 mSv of radiation, on average. So, four consecutive head CT scans would mean a cumulative dose of around 6 mSv, which is still far from the 50 mSv threshold for increased cancer risk.  But this does not take into account other sources of radiation you may have (like additional x-rays).  As a rule, you should only have the CT scans done if these are absolutely necessary.  Less CT scans mean less cancer risk.

[Sambina_88]

Thank you for answering my question. I'm wondering though, how many doses of mSv do x-rays have? I hope that question made sense. Thanks again =)

[Fernando Roque, MD]

Hi. The radiation dose received by having an x-ray done will depend on the extent of the area being covered (you'll probably receive more radiation from a thoracolumbar x-ray than from a skull x-ray), and how many shots/views were taken.  Just to give you an idea of the radiation dose involved, a typical chest x-ray will expose you to 0.1 mSv, which is a much smaller dose compared with what you will receive from a CT scan.

[Sambina_88]

Thanks again =)

Have a good day!