When it’s time to undergo a bone scan to determine if a fracture is healing or bone density is changing, clients often share with me their worries about radiation exposure and if there is anything they can do to protect bone from radiation damage. These are often clients who have had cancer or multiple fractures and know they’ve already been exposed to a fair bit of radiation from prior x-rays. The idea of still more exposure makes them reluctant to consider yet another scan.
These concerns are valid: each time energy from x-rays or gamma radiation interacts with human tissues, chemical reactions occur that generate free radicals — negatively charged oxygen-hydrogen molecules that readily react with many other molecules. These free radicals are capable of damaging DNA, which is what leads to the increased risk of cancers in people with radiation exposure.
I bet each of you has been exposed to imaging with ionization radiation — be it from a dental x-ray, bone density scan, chest x-ray, mammograms or CT scan. In fact, per capita radiation exposure from medical procedures (excluding dental or x-ray radiotherapy) has increased 600% since 1982! While medical imaging can be a life-saving tool, it’s an unfortunate truth that having scans means radiation exposure, and radiation exposure is cumulative. But that doesn’t mean there’s nothing you can do.
A few years ago I underwent a CT scan after experiencing an episode of abdominal distress. It was not a time-sensitive issue, but my doctor wanted a CT scan to rule out any pathology. My attention was on knowing if I had a serious abdominal issue — what I didn’t think about at the time was the collateral cellular DNA damage from the CT scan.
This experience, and my clients’ concerns, inspired me to start using (and recommending) an Antioxidant Protocol designed to help protect against DNA damage from medical radiation exposure. It’s based on a protocol developed by researchers at the University of Toronto. I share this protocol with my clients who worry about their radiation exposure — and am happy to share it with you. (Velauthapillai et al. 2017)
In coming up with a way to protect against damaging radiation, University of Toronto researchers hypothesized that front-loading the body with antioxidants — which are positively charged chemicals that could attach quickly to free radicals before they had a chance to damage tissues and cellular DNA — might help limit the harms of radiation screening and therapy. The idea was that the antioxidants might quench the radiation-generated free radicals before they could damage the DNA.
They studied this question by obtaining blood samples from a group of patients scheduled to undergo an x-ray or other radiation exposure. One set of patients was given a course of oral antioxidants before their exposure, while the other simply underwent the exposure without pretreatment. The researchers then took another blood sample after the exposure and compared it with the pre-exposure sample. They found that those patients who did not have the antioxidants had significantly more evidence of cellular damage compared to those who did. This means that their hunch that antioxidants could help limit the damaging activity of free radicals was correct.
Our protocol for patients is based on the one used in the Velauthapillai study, consisting of:
We suggest that, if possible, patients should take these antioxidants at least five days prior to radiation exposure to have sufficient antioxidant levels in the body at the time of the exposure. This antioxidant protocol should be helpful for radiation exposure that comes from medical scans such as DEXA, mammography, or CT scans.
Not all medical imaging delivers the same amount of radiation exposure. Some common testing techniques, such as in DEXA bone density testing, dental x-rays, chest x-rays and mammograms, expose one to much less radiation than do CT scans. The radiation exposure from nuclear medical imaging and CT scans is multiple times that of conventional x-rays. And, as CT scanning devices become more available, more scans are done each year. In Canada, as of 2018, some 159 CT scans were conducted annually for every 1,000 inhabitants. In the US that figure was 270 CT scans per 1,000 inhabitants. (OECD 2019)
All in all, medical imaging accounts for half of all the radiation exposure in the US, and half of that medical imaging radiation exposure is a result of CT scanning (Mettler et al. 2008a). Of note is the fact that CT scan procedures are becoming more common amongst children and a 9.5-year Australian study (Mathews et al. 2013) reported that anywhere from 0.3% to 1% of all cancers among pediatric patients could be attributed to CT scanning.
The illustration below (adopted from Mettler et al. 2008b) depicts the varying levels of radiation exposure from various types of medical imaging. To put this illustration in perspective, the average US annual background radiation exposure is 3 (mSv). CT scans, as a whole, range in radiation exposure from 2 to 20 mSv and the nuclear imaging cardiac stress-rest (thallium 2.1 chloride) test exposes the individual to 40.7 mSv of radiation. Consider that the Canadian Nuclear Safety Commission mandates that workers not be exposed to more than 50 mSv in one year and not more than 100 mSv in a five year period! (Velauthapillai 2015)
Protecting ourselves from all levels of radiation exposure is something that will only enhance our health. Best of all, it’s not hard to do when we take a commonsense approach:
I hope this information helps you prepare for your upcoming testing. And don’t forget, these antioxidants also have amazing benefits for your bones!
Mathews, J. D., et al. 2013. Cancer risk in 680 000 people exposed to computed tomography scans in childhood or adolescence: Data linkage study of 11 million Australians. British Medical Journal 346:f2360.
Mettler, F. A., Jr., et al. 2008a. Medical radiation exposure in the U.S. in 2006: Preliminary results. Health Physics 95(5):502-507.
Mettler, F. A., Jr., et al. 2008b. Effective doses in radiology and diagnostic nuclear medicine: A catalog. Radiology 248(1):254-263.
OECD. 2019. Computed tomography (CT) exams (indicator). doi: 10.1787/3c994537-en. (accessed on 10 September 2019).
Velauthapillai, N. 2015. Oral antioxidants for radioprotection during medical imaging examination. University of Toronto, Institute of Medical Science, Master’s Thesis, 2015.
Velauthapillai, N., et al. 2017. Antioxidants taken orally prior to diagnostic radiation exposure can prevent DNA injury. Journal of Vascular and Interventional Radiology 28(3):406-411.