Information Notice No. 90-58: Improper Handling of Ophthalmic Strontium-90 Beta Radiation Applicators
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR SAFETY AND SAFEGUARDS
WASHINGTON, D.C. 20555
September 11, 1990
Information Notice No. 90-58: IMPROPER HANDLING OF OPHTHALMIC
STRONTIUM-90 BETA RADIATION APPLICATORS
All Nuclear Regulatory Commission (NRC) medical licensees.
This notice is intended to inform users of strontium-90 (Sr-90) eye
applicators of improper handling practices that resulted in unnecessary
radiation exposures to the skin. This notice also serves to remind
licensees of the importance of handling devices in accordance with
manufacturers' instructions. It is expected that licensees will review this
information for applicability to their own procedures for Sr-90 eye
applicator use, distribute this notice to those responsible for radiation
safety and to users of the Sr-90 eye applicator, and consider actions, if
appropriate, to preclude similar situations from occurring at their
facilities. However, suggestions contained in this notice do not constitute
any new NRC requirements, and no written response is required.
Description of Circumstances:
The following cases illustrate improper handling techniques for Sr-90 eye
Case 1: A physician sterilized the treatment end of a Sr-90 eye applicator,
on six separate occasions, by touching its surface with alcohol swabs held
in his fingers. The cumulative dose associated with this technique was
estimated to be 50 rem to the fingertip; this is well in excess of the
extremity dose limit of 18.75 rem per quarter.
Case 2: For years, a physician treated patients by opening the eyelids with
his bare fingers and positioning the applicator. By handling a typical
100-millicurie eye applicator in this fashion, the dose to the fingers per
treatment has been estimated to be 0.4 rem. A physician practicing under
these circumstances would exceed the quarterly extremity dose limit of 18.75
rem by providing approximately 50 treatments per quarter, or 4 treatments
Case 3: During routine inspection at a licensee's facility, the physician
was asked to show his eye applicator to the inspector. The physician
retrieved the applicator from its secured storage location and pointed it
directly at the inspector, who was standing approximately 18 inches away
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from the unshielded source tip of the applicator. The radiation field from
the applicator, 18 inches away, was approximately 13 rad per hour. To avoid
unnecessary exposure, the applicator should always be shielded or pointed
away from individuals, except during actual treatment.
All licensees are reminded of the importance of ensuring the safe
performance of licensed activities in accordance with NRC regulations and
the requirements of their licenses. Eye applicators are designed to deliver
intense doses of beta radiation for the treatment of superficial eye
diseases. The sealed source mounted on the tip of each applicator has a
nominal activity of approximately 100 millicuries of strontium and
yttrium-90 in equilibrium, and delivers a contact dose rate on the order of
60 rad per second.
The NRC dose limits for extremities (hands, forearms, feet, and ankles) and
skin of the whole body are 18.75 rem and 7.5 rem per quarter, respectively.
Contact between the source tip of the applicator and the skin could result
quickly in a radiation dose in excess of NRC limits. Repetitive activities
such as tip sterilization or positioning the applicator for treatment, when
performed with bare hands and in close proximity to the tip of the
applicator, over a period of several seconds per event, may result in
radiation doses in excess of NRC limits. Therefore, compliance with NRC
license commitments and manufacturers' handling instructions are important
in maintaining exposure levels as low as reasonably achievable.
The cases described above illustrate an incomplete understanding of proper
handling procedures and the skin exposures that could occur from improper
handling. NRC regulations require that users of eye applicators evaluate
potential safety hazards, ensure safe operations at their facilities, and
follow manufacturers' and NRC's safe handling instructions, described below:
Typical Manufacturer's safe handling instructions:
1. Sterilize the applicator by either: (a) immersing the applicator
in alcohol in a shielded container, or (b) placing a cotton swab,
sponge, or gauze, dampened with a sterilizing agent, on a flat
surface and wiping the treatment end of the applicator across the
swab, sponge, or gauze, instead of holding it with the finger.
2. The applicator should only be held by its shielded handle, at all
times. The beta shield should be positioned as close to the source
as possible, during treatment, to minimize exposure to the user.
3. The active face of the applicator must not be viewed directly,
but only through the shield provided, or equivalent protection.
4. Never point the unshielded treatment end of the applicator toward
any individual, especially toward the eyes, except during patient
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5. Use manufacturer-supplied handling tongs for the placement and
removal of beam collimating masks on the applicator tip. The
collimator masks should be fitted and removed with the source
facing away from the user.
6. Always minimize the time that the applicator is out of the shielded
storage container. The storage case should be locked and secured,
to prohibit unauthorized access to the applicator.
7. In the event of apparent or probable damage to the source, it
should immediately be placed into the storage case. The storage
case should be wrapped or placed into a plastic bag and secured.
The Radiation Safety Officer should be notified for consultation
In addition to following the manufacturer's handling instructions, licensees
are required to submit rules for safe handling of Sr-90 eye applicators at
the time of license application, amendment, or renewal. Licensees may
submit a copy of their own rules for safe handling, or NRC's "Rules for
Safely Handling a Strontium-90 Eye Applicator," as described in "Information
to be Submitted When Requesting Possession and Use of Sr-90 as Ophthalmic
Applicator," dated March 1982, and listed below:
NRC's "Rules for Safely Handling a Strontium-90 Eye Applicator":
*1. Wear your personnel dosimeter(s) whenever you handle the Sr-90 eye
applicator. Finger ring-type dosimeters should be worn with the
detector on the palm side of the hand.
2. Remove the Sr-90 eye applicator from its secured storage location
just before use. Do not leave it out any longer than necessary.
3. After removing the Sr-90 eye applicator from its secured storage
a. Do not touch the treatment end of the applicator with your
hands or other portion of your body,
b. Always hold the applicator by its handle, and
c. Except during patient treatment, do not point the treatment end
of the applicator toward another person, especially toward the
4. If the applicator is to be sterilized, place on a flat surface, use
a cotton swab, sponge, or gauze dampened with a sterilizing agent,
then wipe the treatment end of the applicator across the swab,
sponge, or gauze. Do not sterilize by holding the swab or gauze in
*It is strongly recommended that Thermoluminescent Dosimeter (TLD) ring
or film type badges be worn when handling a Sr-90 eye applicator.
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5. During treatment, hold the patient's eye lids open with tape or
other device, not with your fingers.
6. Immediately after treatment and/or resterilization, return the
Sr-90 eye applicator to its storage container and to its secured
location (e.g., locked cabinet).
7. Do not remove any metal or plastic inserts from the
manufacturer-supplied storage container. These items are generally
a part of the container's shielding. Removal of these items can
lead to excessive and unnecessary radiation exposures.
No written response is required by this information notice. If you have any
questions about this matter, please contact the appropriate regional office
or this office.
Richard E. Cunningham, Director
Division of Industrial and
Medical Nuclear Safety
Office of Nuclear Material Safety
Technical contact: Janet R. Schlueter, NMSS
Hector Bermudez, Region II
1. List of Recently Issued NMSS
2. List of Recently Issued NRC
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