United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 86-95: Leak Testing Iodine-125 Sealed Sources in Lixi, Inc. Imaging Devices and Bone Mineral Analyzers

                                                            SSINS No.:  6835
                                                            IN 86-95 

                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                    OFFICE OF INSPECTION AND ENFORCEMENT
                           WASHINGTON, D.C. 20555

                              November 10, 1986

Information Notice No. 86-95:   LEAK TESTING IODINE-125 SEALED SOURCES IN
                                   LIXI, INC. IMAGING DEVICES AND BONE MIN-
                                   ERAL ANALYZERS 

Addressees: 

All NRC licensees authorized to use Lixi, Inc. imaging devices or any other 
bone mineral analyzer with a sealed source containing iodine-125. 

Purpose: 

This notice is to alert licensees of a recent incident where the normal 
means of testing the sealed source in such devices for leakage was 
ineffective and to suggest alternate means of leak testing. It is suggested 
that licensees review this information for applicability to their facilities 
and consider actions, if appropriate, to preclude similar problems at their 
facilities. However, suggestions contained in this information notice do not 
constitute NRC requirements; therefore, no specific action or written 
response is required. 

Description of Circumstances: 

Lixi, Inc. imaging devices include a sealed source containing 220 to 450 
millicuries of iodine-125 and function much like an X-ray fluoroscope. The 
source has to be tested every 6 months to determine if there is any leakage 
of iodine-125. Licensees who keep sources longer than 6 months are required 
by license to perform this test and send the test samples out for analysis. 
This test is now performed by using an alcohol-moistened Q-tip and a dry Q-
tip to wipe certain portions of the source holder as specified in the 
instructions. The purpose of the test is to determine if any particulate 
iodine-125 is on the sample Q-tips, which would indicate the source was 
breached and would have to be replaced to avoid a contamination problem. 
However, a recent incident at the Lixi, Inc. facility showed that the 
alcohol and dry wipes are not an adequate means of detecting a leaking 
source. 

During the investigation of the incident, it was found that two sources that
had been returned for exchange were leaking. Alcohol and dry wipes did not 
reveal any removable iodine-125 on the various surfaces because the escaping
iodine-125 came out in gaseous form rather than as particulate matter. As a 
result, about 15 people inhaled small amounts of iodine-125 which deposited 
in their thyroids. 


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                                                       November 10, 1986 
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The iodine-125 was apparently adsorbed on carbon containing material such as
cardboard, rubber bands, styrofoam, and charcoal that was near the escaping 
gas. A survey of these materials revealed elevated radiation levels. Through
these direct surveys and a series of air samples U*sing filter media 
containing charcoal, the ruptured sources were located and the airborne 
contamination problem was resolved. 

Discussion: 

Licensees who perform leak tests on their Lixi, Inc. imaging devices should 
be aware that the current practice of using alcohol and dry wipes is not an 
adequate means of detecting a leaking iodine-125 sealed source. Lixi, Inc. 
will be sending a revised leak testing procedure to its customers in the 
near future, In the meantime, licensees who are returning source heads for 
exchange should include charcoal in the form of granules or a solid piece in 
the package with the source head. When Lixi, Inc. receives such packages, it 
will survey the charcoal for an indication of leakage. A sodium-iodide 
crystal (thin window) detector (or one of similar sensitivity) is required 
to detect the low levels of radioactivity that would be encountered in such 
surveys. 

During the incident investigation, granulated charcoal was placed on a Q-tip
that was then held for several minutes at the window in the source head to 
verify leakage. The gaseous iodine-125 that adsorbed onto the charcoal was 
easily identified with a crystal detector. 

Until the revised procedure arrives from Lixi, Inc., it is suggested that 
licensees use the above method for identifying a leaking source. The 
granulated charcoal Q-tip may be placed in the plastic envelope that is 
included in Lixi's leak test kit and forwarded to a consultant with adequate 
instrumentation for analysis. 

If you have any questions regarding this matter, please contact the Regional
Administrator of the appropriate NRC Regional Office or this office. 



                                   James G. Partlow, Director 
                                   Division of Inspection Programs 
                                   Office of Inspection and Enforcement 

Technical Contact:  J. Metzger, IE 
                    (301) 492-4947 

Attachment:    List of Recently Issued IE Information Notices 
Page Last Reviewed/Updated Tuesday, November 12, 2013