Dear Gerd,
One of the more detailed guides to implants and their safety
properties is the following book:
Pocket Guide to MR Procedures and Metallic Objects: Update 2001
by Frank G. Shellock
Generally speaking pacemakers are not allowed in MR-scanners although
they in principle may not be harmed by a limited field strength. Most
of the documented cases of deaths during MR-procedures (5) that I am
aware of, are indeed related to patients with pacemakers. I suspect
it was the heart condition of the patient that caused these deaths.
Also, to say that the pacemaker function fine in saline outside the
body may not be the same as to say that it will work in a patient
with a heart condition. Finally the rather arbitrary 5 Gauss limit
that we generally observe, is in my experience more detrimental to
computers than to people. For all computers to be entirely happy I
would set the limit to 1 Gauss. But that is another story.
Spin up,
73, Peter
At 16.13 +0200 04-05-03, Dr. Gerd Gemmecker wrote:
>Hi colleagues,
>
>a few weeks ago I had a discussion with our university
>safety commissioner. Normally this is always a very delicate
>business: one careless word can mean years of trouble.
>
>However, this time he surprised me with a new information
>(at least for me! - although it is already from 2000) he
>had found in the internet:
>a clinical study performed on an "in vitro model" (pacemakers
>in a vessel with salt water, plus "in vivo": 55 patients with
>pacemakers (44 different models) in a 0.5 T MR tomograph.
>Result: no adverse effects nor even the slightest deviation
>in the pacemaker parameters could be detected! Admitted,
>the pacemakers were set on "asynchronous mode" (i.e., a
>fixed stimulation rate) to let them run more stable.
>
>but at least here is a number (0.5 T = 5000 Gauss)
>with some reference (that can be quoted!)that it is safe.
>And there is even a website discussing the results in German
>(www.herzschrittmacherpatient.de).
>
>Our commissioner was very pleased with this and will put
>it in his next report, when talking about the "safety limit"
>of 5 Gauss that we are obeying.
>
>ah yes, the source is:
>"MR imaging and cardiac pacemakers: in-vitro evaluation and in-vivo
>studies in 51 patients at 0.5 T."
>Sommer T, Vahlhaus C, Lauck G, von Smekal A, Reinke M, Hofer U,
>Block W, Traber F, Schneider C, Gieseke J, Jung W, Schild H.
>Radiology. 2000 Jun;215(3):869-79.
>
>hope you might find this useful,
>
>gg
>
>--
>
>==========================================
>
>PD Dr. Gerd Gemmecker
>Department Chemie, Organische Chemie II
>TU Muenchen
>Lichtenbergstr. 4
>D-85747 Garching
>Germany
>
>Tel. +49 (89) 289-13308
>Fax +49 (89) 289-13210
>e-mail: Gerd.Gemmecker_at_ch.tum.de
>Internet: http://www.org.chemie.tu-muenchen.de/people/gg
--
_at_ _at_
..
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Received on Mon May 03 2004 - 18:40:30 MST