foodconsumer.org: Some basics about radiation and cancer

Some basics about radiation and cancer
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admin on 12/15/2009 02:33:00
 
Understand radiation cancer risk
Is radiation a cancer-causing agent or carcinogen?
Yes, ionizing radiations like x-ray used in computed tomography scan or CT scan
are recognized by the U.S. National Toxicology Program as a carcinogen.  In
fact, radiation is the most studied carcinogen in history.
Is there any threshold of exposure to radiation that is considered safe?
Safe or not, it all depends on your definition.  One needs to know that just
because you are exposed to some radiation does not mean you will definitely get
cancer. On the other hand, no one can guarantee that you will not get cancer
after you receive certain dose of radiation from a CT scan or conventional x-ray
diagnostic tool.
It has become clear that any tiny amount of radiation can cause mutations, which
of course may or may not lead to development of cancer.
In addition, people may need to remember that radiation-induced damage is
cumulative over the years.
In a sense, there is no safety threshold for radiation.
How does radiation cause damage to DNA?
Radiation causes ionizations in molecules in living cells, which injure the
cells.  The radiation-induced damage may or may not be repaired.  Cells
receiving severe damage may just die, which would not result in any consequence
in the future. The problem with radiation is that some injured cells cannot be
repaired and they will produce abnormal cells particularly in children, which
may lead to development of cancer.
We receive background radiation every day.  Do we have to worry about medical
radiation?
There are a couple of things different between the two types.  Medical radiaiton
comes often in a higher dose than that of environmental radiation. For instance,
one may get background radition in 300 MREM in a year. But one chest-ray gets
you 30 or 50 MREM. One CT scan can be 50 to 100 times higher than chest x-ray.
And secondly, according to John Gofman, MD PhD, a distinguished nuclear
physicist and medical physician, medical radiation poses twice as effective as
the radiation from our environment at causing damage.  Medical radiation is more
focused and results in more severe injury to cells.
Do all medical radiations pose the same cancer risk?
No. The risk depends on dosage, the dose rate, age, sex, lifestyle and the
individual's genetics among other things.
Some medical tools like CT scans use much higher doses than chest x-ray.  CT
scan performed on abdomen/pelvic uses higher doses of radiation than that used
for the head.
Who are at higher risk of radiation-induced cancer?
Children are at higher risk of radiation-induced cancer.