Extremity Dose Reduction. By Aggie Barlow, CHP, MS, MBA. Over or unnecessary exposure. There have been incidents at other institutions where workers have received radiation exposures to their hands which were over regulatory limits. In almost every case, these exposures
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By Aggie Barlow, CHP, MS, MBA
There have been incidents at other
institutions where workers have received
radiation exposures to their hands which
were over regulatory limits.
In almost every case, these exposures
As Low As Reasonably Achievable -
working every day, during every procedure
involving radioactive material [RAM] in such
a manner as to keep exposure doses low.
Regulatory agencies expect ALARA practices.
50 Rem per year limit for extremities [ex. hands or wrists]
Experiments in progress
One does not have to be working with
large activities to receive large radiation
Even microcurie amounts can result in high
extremity doses when performing repetitive operations.
proximity to radiation sources
Reasonably Achievable Philosophy
Work pressures and workloads must
not be allowed to interfere with appropriate
radiation safety practices.
Do not pick up stock vials of high energy
beta emitters or gamma emitters directly
with the hand.
Use tongs whenever
feasible. Rubber coating
on tongs ensures grip.
Stock vials contain concentrated solutions.
Store and carry them in the [lead] pig or other shipping container.
Place stock vials in secondary containers
for transport between rooms. Increased
distance from the vial reduces your exposure.
The bottom of the container is generally
designed to securely hold the vial in position for removal of an aliquot without the need for the worker to hold the stock vial itself. The top of many containers can also be used for hands-free opening of the stock vial.
Containers are designed to hold vials in place
Take aliquots from stock vials without removing the vial from the container whenever feasible. This keeps your fingers farther away from the RAM.
Handling vials directly from the container whenever feasible. This keeps your fingers farther away from the RAM.
increases exposure to
Avoid this whenever
possible. Use the
container, rubber coated tongs or other remote handling
means.Techniques to avoid
If you must pick up a stock vial or tube of RAM, keep your fingers as far away from the contents as possible. That is, pick it up from the top, so that your thumb is not under the
container near the contents at the bottom.
Gently tap liquid solutions to the bottom of the container.
Poor Technique vs Good Technique
Carry tubes containing RAM in a tube
rack or other container so that your
fingers are at an increased distance from
The radiation dose rate varies inversely
as the square of the distance from the
source for electromagnetic radiation.
Therefore, keep your hands as far from
the radioactive material as feasible.
One millicurie of I-125 has a dose rate of
> 500 mRem/hr on contact, but
< 2 mRem/hr at 6 inches [such as when
handled with rubber coated tongs]
Use of double gloves is strongly advised
when handling radioactive material.
Check your hands for contamination frequently while you work.
If contamination is found, change to a new
pair of gloves. Be sure to survey hands.
When done using RAM, survey your hands
using a portable survey meter. Perform a
slow, careful survey of both sides of
the hand. But sure to include both sides
of your thumb, your wrists and lab coat
Contact Tufts Police at 6-6911 for emergencies
Also have someone call Health Physics Group- Boston [6-6168].
In Grafton or Medford call RS/EHS at 6-3615
After hours call 636-6911 and Campus Police will help you get
Begin hand washing procedure using soap and warm water.
Wash, dry and resurvey the skin. Continue
washing if contamination is still present.
Seek Health Physics advice before
using abrasive cleansers.
Call 6-6911 for all Emergencies 24/7,
Call Radiation Safety Officer at 6-3615 or
617 308-3781 [cell],
Tufts EHS/Rad Safety Main Office
number is 6-3615.
After hours, Campus Police will
summon the personnel to assist you.
Contact Health Physics Group or Tufts RS/EHS at 636-3615 or 636-3450