United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 90-58: Improper Handling of Ophthalmic Strontium-90 Beta Radiation Applicators

                                UNITED STATES
                        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 


Addressees:  

All Nuclear Regulatory Commission (NRC) medical licensees. 

Purpose: 

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 
applicators: 

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 
per week. 

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 


9009050223 
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                                                       IN 90-58 
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                                                       Page 2 of 4 


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. 

Discussion: 

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 
         treatment. 
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                                                       IN 90-58 
                                                       September 11, 1990 
                                                       Page 3 of 4 


     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 
         and action. 

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 
         location: 

         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 
             eyes. 

     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 
         your hand.

     *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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                                                       IN 90-58 
                                                       September 11, 1990 
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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
                                and Safeguards


Technical contact:  Janet R. Schlueter, NMSS
                    (301) 492-0633

                    Hector Bermudez, Region II
                    (404) 331-7880

Attachments:
1.  List of Recently Issued NMSS
      Information Notices
2.  List of Recently Issued NRC
      Information Notices

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