Do any of the universities, companies, hospitals or research institutions
have any policies regarding the use of electron microscopy by pregant
employees? Is there any literature available on the topic?
Is the advice not to use EM at all during the 9 months, or maybe only
during critical periods of development?
In searching the archives I only found one reference on this topic.
Any help would appreciated.
Patrick Diehl
Materials Science Department
University of North Texas
diehl@unt.edu
I have sheparded three pregnancies (users, not me) on my 200 kV TEM and I
found it a good way to get the instument monitored and thoroughly tested.
The last one wore a accumulation monitor at all times and found a curious
phenomenon: she accumulated more radiation when sitting at her desk, next to
the cinder-block wall in the next room, than when she was working at the TEM
at 200 kV. These instruments, when assembled and used properly and monitored
in case of leaks after maintenance, leak less x-rays than a TV. I believe
the regulations regarding radiation exposure are considered valid for
pregnant women.
Mary Mager
Electron Microscopist
Metals and Materials Eng., UBC
6350 Stores Rd.
Vancouver, B.C. V6T 1Z4
CANADA
tel:604-822-5648, fax:604-822-3619
e-mail: mager@unixg.ubc.ca
I have got two healthy daughters (the youngest one is 10 weeks). During
the whole period of both my pregnancies I have worked with electron
microscopy (TEM, SEM, low vacuum SEM and environmental SEM).
Risoe National Laboratory is a former Atomic Energy Commission Research
Establishment, so we still have health physicists around. They were
consulted as soon as I realised that I was pregnant. The health
physicist measured the radiation level at all our TEMs and SEMs. Only
the background level of approx. 0.06 microSv/h was found. During the
my pregnancies I wore two badges that checked the radiation
continuosly. Nothing above background level was detected.
Charlotte C. Appel
Materials Research Department
Risoe National Laboratory
DK-4000 Roskilde DENMARK
c.c.appel@Risoe.DK
first 3 months. The Nuclear Reg. Comm. limits this exposure to <500 mRem for the 9
months. This SHOULD be a huge value compared to any exposure from any EM
unless it is a HVTEM that is improperly setup (you must stay out of the chamber
when running <g>). A SEM running 30 kV. cannot produce any x-rays over 30 keV -
Most are well under. These relatively soft x-rays are (typically) completely
shielded by the column and chamber walls....Consult your manufacutrer for
detailed exposure rates. I think you will find that a cross country air
flight (or 9 months in Denver vs. a sea level city) will expose you to more radiation
than will 9 months in front of the EM.
Woody.N.White
Woody.N.White@mcdermott.com
Everyone who uses radiation-producing equipment should be monitored.
We have ion-chamber dosimeters for occasional users and film badges for
people who are around the instrument every day. The limit for exposure for
pregnant women is 500 millirem over the course of the pregnancy, but this
amount should not happen in a short period. There is an unofficial limit
of 50 millirem per month. These numbers come from the experts in the NY
State Department of Health. For exposures to x-rays, rad and rem are equi-
valent, and 1 rad (Radiation Absorbed Dose) is 100 ergs per gram.
If you have no capability for monitoring users, the next best thing
is to use a detector, such as a Geiger counter or an ion chamber, to deter-
mine whether the radiation near the microscope is different from background.
If there is no difference between the radiation measured before the scope
is turned on and when it is cranked up fully, then you can be reasonably
sure there is no danger (assuming you have a detector which is sensitive
to the radiation your scope produces); however, this probably won't satisfy
any legal requirements.
William Tivol
tivol@wadsworth.org
There is no danger from contemporary microscopes which are well
maintained and monitored. The problem exists with chemicals.
Cacodylate buffer if used in a laboratory eventually contaminates
bottles, hoods, etc., with fine arsenic dust. Then there is the lead
stain and the UA. Anyone pregnant should not be weighing out any
chemical containing heavy metals. Extreme care needs to be taken with
other noxious things such as glut, paraform, xylene, propylene, etc.
During my time in another lab, there occurred a chemical spill - the
holding tank backed up into the lab. A mixture of the above seeped up
through the floor drains. My coworker attempted to contain the spill
with a properly fitted mask. At the time she was 12 days pregnant. At
seven months she gave birth to a badly deformed baby which lived only for
an hour. After exhaustive investigation, it was decided that the uterine
fluid had been contaminated with heavy metals. The enormous quantity of
fluid gave her the appearance at seven months of a 10 months preganancy,
at least.
Anyone who is not protected by birth control and might be pregnant at any
time should not be weighing out questionable material, and should take
extreme care with being gloved, etc., at all times.
So long,
Hildy
HILDEGARD CROWLEY
hcrowley@odin.cair.du.edu
This is not so curious. The potassium-40, naturally occurring in
concrete is a well-known source of radiation. If the user had her desk in
Denver, there would have been an additional component from the greater
cosmic ray flux at high altitude.
William Tivol
tivol@wadsworth.org
the lab is pregnant. I have a colleague who is pregnant now, and she does not
do resin embedding. She does cut cured blocks,stain them with uranyl acetate
and lead citrate, and look at them on the TEM. Is this normal procedure in
other labs? Should she wear a mask when staining?
Linda Chicoine
Center for Cell Imaging
Yale University
New Haven, CT
Linda.Iadarola@quickmail.yale.edu
I run a morphology core where a TEM is used every day. Last year when I
was pregnant, I called Health Physics who monitored the scope and me for a
period of time. There was absolutely no leakage fromm the column.
Although every scope is different, ours is brand new, you can always have
your environmental people come out and check for leaks. I believe them to
be safe - my son had all of his fingers and toes.
Cheri Owen
cowen@cmb.biosci.wayne.edu