[ RadSafe ] News Article: High radiation dose with CT angiography warrants caution in children

[John Jacobus]

Nothing really new here.  I just onder how many
childen get CT angiography.

http://www.auntminnie.com/index.asp?Sec=sup&Sub=car&Pag=dis&ItemId=77277&wf=1236

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High radiation dose with CT angiography warrants
caution in children
8/27/2007
By: Reuters Health
 
NEW YORK (Reuters Health), Aug 27 - Radiation doses as
high as ten times the annual natural background
radiation can occur during cardiac-gated CT
angiography in pediatric populations, new research
shows. For this reason, this modality should not be
routinely used in children until further work can
determine appropriate imaging parameters.

This study is "the first, to the best of our
knowledge, to look at gated CT coronary angiography in
children. Other studies have assessed dose in adults
for this type of exam but children are more
'radiosensitive' due to young age and increased life
span during which a complication could develop," lead
author Dr. Caroline L. Hollingsworth told Reuters
Health. 

As they report in the July issue of the American
Journal of Roentgenology, Dr. Hollingsworth and
colleagues performed ECG-gated cardiac CT angiography
on an anthropomorphic phantom of a 5-year-old child
using a 16-multidetector-row CT scanner with
adult-type settings.

Metal oxide semiconductor field effect transistor
technology (MOSFET) was used to measure various organ
doses. The effective dose was also determined through
calculation of the dose-length product (DLP). 

The breasts, lungs, and bone marrow received the
highest doses -- up to 12.1 cGy. Lower radiation doses
were seen with 80 kVp/385 mA scan settings than with
120 kVp/220 mA settings. 

DLP effective doses were higher than those obtained
with MOSFET measurement. The highest DLP dose noted
was 28.4 mSv, roughly ten times the annual natural
background radiation. For comparison, Dr.
Hollingsworth said that with nongated chest CT in
children, the dose rarely exceeds 6 mSv.

"I think pediatricians and those who care for children
who may need specialized heart evaluation need to be
aware that gated CT angiography can impart a very high
radiation dose, particularly if appropriate pediatric
protocols are not set up by the radiologist
responsible for the exam," Dr. Hollingsworth
emphasized. 

"Caregivers and physicians need to decide that CT
angiography is a better choice than another modality
such as magnetic resonance, and then protocols need to
be adjusted so that the scan technique addresses the
clinical question," she added.

By Anthony J. Brown, M.D.

Last Updated: 2007-08-24 17:36:03 -0400 (Reuters
Health)

Am J Roentgenol 2007;189:12-18.

Related Reading

JAMA study: Coronary CTA poses substantial cancer risk
in select patients, July 17, 2007

+++++++++++++++++++
"All of the old-timers knew that subprime mortgages were what we called neutron loans --  they killed the people and left the houses. . . .
"LOUIS S. BARNES, a partner at Boulder West, a mortgage banking firm.

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com


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