Medical Radiation Basics
• Studies are based on Atomic Bomb Data (Life Span Studies)
• Medical radiation and the A-bomb are not the same, but experts have deemed the data to be reasonable.
• Background radiation = 3.5 mSv/year (just from living on the Earth – solar and Radon exposure)
• Background Cancer Incidence = 420:1000 (42%) [Mortality is 200:1000] (Yikes!)
• Radiation effects are present not only at high dose radiation levels, but also effects of low dose radiation (0-100 mSv; where medical radiation falls)
• At 10 mSv Lifetime Attributable Risk of developing a cancer is 1:1000
• So 10mSV exposure will increase the cancer incidence to 42.1%… big deal?
• Well, it can be: particularly when you consider the population as a whole and add up all of the CTs that are being done. This increase has been shown to be measurable and significant.
Kids are at greater risk:
- More radiosensitive tissues
– More time for an individual insult to develop into cancer
– More time to be accumulate more radiation (one CT begets another)
Radiation adds up:
- CXR = 0.1 mSv (~10 days worth)
– Head CT = 2 mSv (~8 months worth)
– Chest CT = 7 mSv (~2 years worth)
– Abd/Pelvis CT = 10 mSv (~3 years worth)
– Lumbar CT = 15 mSv (~5 years worth)