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Can Radiation from Cardiac CTA
Cause DNA Damage?
Radiation exposure from cardiac
computed tomographic angiography
(CTA) may cause DNA damage, according to a recent study published in
JACC: Cardiovascular Imaging.
The use of CTA has grown dramatically over the last decade, but a single
cardiac CTA can expose patients to
a radiation dose equivalent to having 150 chest x-rays. This has raised
concern from patients and physicians
about the potential effects of radiation
exposure.
The researchers, led by Patricia K.
Nguyen, MD, examined 67 patients
undergoing cardiac CTA between
January 2012, and December 2013,
estimating the radiation dose to the
body and blood of each patient using
phantom dosimetry. They found that
after radiation exposure from CTA
at doses > 7.5 mSv, 70% of patients
had ≥ 2% increase in phosphorylation
of at least one DNA damage marker,
indicating that at least 200 of 10,000
cells per patient had evidence of DNA
damage. The extent of DNA damage
was correlated with the amount of
radiation exposure. No damage was
observed in patients undergoing cardiac CTA at doses < 7 mSv.
Additionally, 60% of patients had
at least a two-fold increase in apoptosis, or programmed cell death, with
the median number of cells undergoing apoptosis estimated at 0.7%.
The degree of apoptosis was more
strongly correlated with the extent
of DNA damage than the amount
of radiation exposure. However,
the majority of damaged cells were
repaired and most patients did not
have detectable DNA damage 2 hours
after radiation exposure from cardiac
CTA. While most damaged cells were
repaired, a small percentage of cells
died. In a few patients, residual DNA
damage persisted and continued activation of cellular response pathways
was detectable up to 1 month later.
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CardioSource WorldNews
According to Nguyen and colleagues,
“These findings raise the possibility
that radiation exposure at > 7.5 mSv
from cardiac CTA may cause DNA
damage that can lead to mutation
if damaged cells &R