Personal Radiation Dosimeter
What does the dosimeter do?
A radiation dosimeter
or badge does not provide protection but detects and measures
radiation that you have been exposed to. The badge will detect
high-energy beta, gamma or x-ray radiation. Dosimeters
cannot detect low energy beta radiation from some isotopes,
including carbon-14, tritium or sulfur-35.
What types of dosimeters are there?
UTHSC-H uses two badges
for most employees, Luxel by Landauer (aluminum oxide dosimeter)
and TLDs (thermoluminescent dosimeter). The Luxel badge measures
whole body dose from x-radiation, gamma radiation and beta
radiation. The TLD measures extremity dose (finger, hands etc.)
from x-radiation, gamma radiation and high energy beta radiation.
The TLD chip is housed in a plastic ring to be worn on your
dominant hand. For more details on the proper procedure for
wearing dosimetry see the section labeled "How do I wear
my dosimeter?"
Who needs a dosimeter?
Radiation workers who operate x-ray
machines, flouroscopy units, certain unsealed and sealed radioisotopes
or are exposed to other sources of gamma or high energy beta
radiation are generally required to wear one or more dosimeters.
The following table provides general badging guidelines for
those who handle radiation sources or equipment. If you meet
the following criteria and do not have a badge, please contact
the Radiation Safety Office at 713-500-5840.
Dosimetry Requirements UTH
No badge is required
if you use:
- 3 H, 14 C, 33 P, 35 S, 125 I
A
Badge is required if you use or work with:
- 32 P or 36 Cl > 10
mCi per protocol
- 86 Rb, 22 Na, 51 Cr, 131 I >5 mCi per
protocol
- X-ray or Fluoroscopy
- PET Imaging / Cyclotron
Facility
- Environmental Health and Safety
How do I get a dosimeter?
New personnel
working with radiation sources or radiation producing devices
must complete and RS-3 Form for Dosimetry during the Basic Radiation
Safety training class . Once Radiation Safety reviews the
form, a dosimeter will be issued if needed.
Do I need a dosimeter if I am pregnant?
Current occupational
radiation control rules impose a special dose limit specifically
for the unborn child (embryo/fetus) of any radiation worker
who formally declares her pregnancy. This dose limit is 500
mR during the entire pregnancy. Normally the dose limit for
a non-pregnant radiation worker is 5000 mrem per year. A pregnant
radiation worker is not required to declare her pregnancy.
However, in order for the Radiation Safety Division implement
any control measures or dosimetry for monitoring, the pregnancy
must be declared in
writing to the Radiation Safety Division. Dosimetry
is not always necessary for a pregnant radiation worker.
If you have any questions or comments, please don't hesitate
to contact our office at 713-500-5840.
How do I wear my ring dosimeter?
The ring badge should be worn
on a finger with the label (white plate) facing the radiation
source, i.e. toward the palm of the hand where the highest
exposure occurs. Protect
the ring badge from contamination by wearing it inside a glove.
Check the badge as part of your routine survey for personal
contamination. Ring badges are available in small, medium and
large sizes; if your ring doesn't fit, please let us know.
When your ring badge is not being worn, keep
it in a location protected from radiation and heat.
How do I wear my whole body dosimeter?
Radiation workers who
are issued whole body badges should wear them on their collar,
mid-torso or waist with the label facing out. The intent is
to wear the badge is the area most likely to receive exposure.
When your whole body badge is not being worn, keep it in a
location protected from radiation and heat.
When do I return my dosimeter?
Dosimeters are issued for two
categories, monthly and quarterly. The
wear dates are printed on the front of the badge, under your
name, as a reminder of when to wear them. Once the wear
period ends, please remove the badge, keep the grey holder,
and return the badge to Radiation Safety. If you are
expecting dosimeters and you do not receive by the third
working day of the month, please call the Radiation Safety
Division for further details.
At the end of the month or quarter, dosimeters
must be returned to Radiation Safety as promptly as possible
to expedite the processing. All badges are processed according
to National
Volunteer Laboratory Accreditation Program accreditated
agency.
What do the results of the dosimeter mean?
The primary occupational
whole body dose limit is 5,000 millirems per year, effective
dose equivalent. The dose limit to the extremities (hands,
fingers etc.) is 50,000 millirems per year.
How do I terminate a dosimeter?
When a Radiation worker leaves
the University or changes work locations, please notify the
Radiation Safety Division to update the records.
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