UNITED STATES 

NUCLEAR REGULATORY COMMISSION 

OFFICE OF FEDERAL AND STATE MATERIALS 

AND ENVIRONMENTAL MANAGEMENT PROGRAMS 

WASHINGTON, D.C. 20555 

October 17, 2007 

NRC INFORMATION NOTICE 2007-35: VARIAN MEDICAL SYSTEMS 

VARISOURCE HDR EVENTS: 

IRIDIUM-192 SOURCE PULLED FROM 

SHIELDED POSITION 

ADDRESSEES

All U.S. Nuclear Regulatory Commission (NRC) medical use licensees and NRC Master 

Materials Licensees authorized to possess or use a Varian Medical Systems VariSource 

High Dose Rate Remote Afterloader (VariSource HDR). All Agreement State Radiation 

Control Program Directors and State Liaison Officers. 

 

PURPOSE

The NRC is issuing this information notice (IN) to alert addressees to recently reported 

events where the use of the emergency manual retract hand wheel on the VariSource 

HDR has caused the active iridium-192 (Ir-192) source to be pulled out of the shielded 

position. It is expected that recipients will review the information for applicability to their 

facilities and consider actions, as appropriate, to avoid similar problems. However, 

suggestions contained in this IN are not new NRC requirements; therefore, no specific 

action or written response is required. 

NRC is providing this IN to the Agreement States for their information, and for 

distribution to their medical use licensees, as appropriate. 

DESCRIPTION OF CIRCUMSTANCES

NRC has received four event reports in the last three years, two of them recently, 

involving the VariSource HDR Ir-192 source having been pulled out of the shielded 

position, while using the manual retract hand wheel. The four events occurred in a 

range of different situations, two occurred during clinical use of the afterloader, one 

occurred during routine QA/QC checks, and the other occurred during student training. 

In one of the four incidents reported, while the patient treatment was being planned, the 

wire containing the dummy (non-radioactive) source did not return during pre-treatment 

preparations. The manual retract hand wheel, which is intended only for the wire 

containing the radioactive source and not for the dummy source, was used by the 

ML072760661
 IN 2007-35 

Page 2 of 3 

physicist in an attempt to retract the dummy source. However, when the physicist turned 

the hand wheel, the active source was pulled out of the tungsten safe. Two of the 

events occurred when the operator of the VariSource HDR attempted to retract a “stuck” 

dummy source with the manual retract hand wheel. Their attempt to manually retract the 

dummy source caused the active Ir-192 source to be pulled out of the tungsten safe. 

The remaining event occurred during a training exercise when an instructor asked four 

students to simulate using the manual retract hand wheel, however, two of the students 

actually turned the hand wheel and caused the active Ir-192 source to be pulled out of 

the tungsten safe. 

DISCUSSION

Three of the four events occurred because the operators used the manual retract hand 

wheel in an attempt to retract the dummy source back into the VariSource HDR unit. 

The fourth event occurred during a training session. The warning label on the manual 

retract hand wheel reads “Warning – Active Source Wire Emergency Retract only. Turn 

the hand wheel for a maximum of 12 turns or until the radiation alarm ceases. Contact 

Varian Service.” Varian filed an initial notification dated September 17, 2007, with NRC 

in accordance with 10 CFR 21.21, following the latest event on July 15, 2007. The 

report delineated the event and the design characteristics of the VariSource HDR unit for 

safe use. 

While potential long-term solutions are being considered, licensees should be aware that 

consequences of the active Ir-192 source being pulled out of the tungsten safe would 

result in the following: 

1. The source would be contained within the unit, but would be unshielded and 

could not be returned to the shielded position. 

2. The exposure rate for a 10 Curie Ir-192 source that has been pulled out of the 

tungsten safe would have an exposure rate of 18 R/hr at 50 cm. 

3. A recovery operation would be needed to retrieve and secure the source. 

4. Treatments could not resume until a new source wire is installed. 

This IN serves as a reminder that the manual retract hand wheel on the VariSource HDR 

units is intended only for the wire containing the Ir-192 source. The manual retract hand 

wheel does not retract the dummy source. In the event that the dummy source is stuck 

in the out position, the console displays Error Code 88. The operators should consult 

the operator’s manual provided by Varian Medical Systems and contact Varian Service. 

Licensees should also read Varian’s Customer Technical Bulletin (CTB) VS-366A, 

“Clarification on the Use of the Emergency Retract Hand Wheel to Prevent Accidental 

Exposure”. The CTB is available at the following website: 

www.varian.com/shared/oncy/pdf/CTB-VS-366a.pdf

In addition, in the event of an emergency where an operator needs to use the manual 

retract hand wheel to return the active Ir-192 source to the shielded position, operators 

should be aware that the number of turns necessary to return the source to the tungsten 

safe may vary. The number of turns may vary depending on how extended the source is 

initially and on any potential for slippage between the pinch rollers and the source wire, 

especially with a freshly lubricated source wire. The VariSource HDR units are designed 
 IN 2007- 35 

Page 3 of 3 

in such a manner that the operator only knows if the source has returned to the shielded 

position when the audible radiation alarms and red light indicator turn off. Operators 

should be aware that if the manual retract hand wheel is turned too many times the 

active Ir-192 source can be pulled out of the tungsten safe. The unit was not designed 

to have a positive lock to prevent the source from being pulled out of the tungsten safe 

or to indicate that the source is in the shielded position. 

CONTACT 

This IN requires no specific action of written response. If you have any questions about 

this IN, please contact one of the individuals listed below or the appropriate regional 

office. 

 /RA/ 

 Janet R. Schlueter, Director 

 Division of Materials Safety 

 and State Agreements 

 Office of Federal and State Materials 

 and Environmental Management Programs 

 

Technical Contact: Tomas Herrera, FSME 

 (301) 415-7138 

 E-mail: txh1@nrc.gov 

Medical Issues Contact: Cindy Flannery, FSME 

 (301) 415-0223 

 Email: cmf@nrc.gov 

Enclosure: List of Recently Issued FSME/NMSS Generic Communications 

Note: NRC generic communications may be found on the NRC public Website, 

http://www.nrc.gov, under Electronic Reading Room/Document Collections. 
 IN 2007- 35 

Page 3 of 3 

in such a manner that the operator only knows if the source has returned to the shielded 

position when the audible radiation alarms and red light indicator turn off. Operators 

should be aware that if the manual retract hand wheel is turned too many times the 

active Ir-192 source can be pulled out of the tungsten safe. The unit was not designed 

to have a positive lock to prevent the source from being pulled out of the tungsten safe 

or to indicate that the source is in the shielded position. 

 

CONTACT 

This IN requires no specific action of written response. If you have any questions about 

this IN, please contact one of the individuals listed below or the appropriate regional 

office. 

 /RA/ 

 Janet R. Schlueter, Director 

 Division of Materials Safety 

 and State Agreements 

 Office of Federal and State Materials 

 and Environmental Management Programs 

Technical Contact: Tomas Herrera, FSME 

 (301) 415-7138 

 E-mail: txh1@nrc.gov 

Medical Issues Contact: Cindy Flannery, FSME 

 (301) 415-0223 

 Email: cmf@nrc.gov

 

Enclosure: List of Recently Issued FSME/NMSS Generic Communications 

Note: NRC generic communications may be found on the NRC public Website, 

http://www.nrc.gov, under Electronic Reading Room/Document Collections.

 ML072760661 

OFC DMSSA/SSSB DMSSA/SSSB DMSSA/MSEA DMSSA/SSSB 

NAME THerrera:tyh JJankovich SWastler for 

CFlannery 

CEinberg 

DATE 10/02/07 10/02/07 10/04/07 10/09/07 

OFC

DMSSA/MSEA FSME/DMSSA FSME/DMSSA 

NAME AMcIntosh RLewis JSchlueter 

DATE 10/09/07 10/17/07 10/17/07 

 OFFICIAL RECORD COPY
Enclosure 

IN 2007-35 

Page 1 of 3 

Recently Issued FSME/NMSS Generic Communications

Date GC No. Subject Addressees 

02/02/07 IN-07-03 Reportable Medical Events Involving 

Patients Receiving Dosages of 

Sodium Iodide Iodine-131 less than 

the Prescribed Dosage Because of 

Capsules Remaining in Vials after 

Administration 

All U.S. Nuclear Regulatory Commission 

medical use licensees and NRC Master 

Materials Licensees. All Agreement State 

Radiation Control Program Directors and 

State Liaison Officers. 

02/28/07 IN-07-08 Potential Vulnerabilities of Timereliant Computer-based Systems 

Due to Change in Daylight Saving 

Time Dates 

All U. S. Nuclear Regulatory Commission 

licensees and all Agreement State 

Radiation Control Program Directors and 

State Liaison Officers. 

03/13/07 IN-07-10 Yttrium-90 Theraspheres® and 

Sirspheres®

 Impurities 

All U.S. Nuclear Regulatory Commission 

(NRC) Medical Licensees and NRC Master 

Materials Licensees. All Agreement State 

Radiation Control Program Directors and 

State Liaison Officers. 

04/04/07 IN-07-13 Use of As-Found Conditions to 

Evaluate Criticality-related Process 

Upsets at Fuel Cycle Facilities 

All licensees authorized to possess a 

critical mass of special nuclear material. 

05/02/07 IN-07-16 Common Violations of the Increased 

Controls Requirements and Related 

Guidance Documents 

All licensees who are implementing the 

U.S. Nuclear Regulatory Commission 

(NRC) Order Imposing Increased Controls 

(EA-05-090), issued November 14, 2005 

and December 22, 2005. 

05/21/07 IN-07-19 Fire Protection Equipment Recalls 

and Counterfeit Notices 

All holders of operating licenses for nuclear 

power reactors and fuel cycle facilities; 

except those licensees for reactors that 

have permanently ceased operations and 

who have certified that fuel has been 

permanently removed from the reactor 

vessel; and except those licensees for 

decommissioned fuel cycle facilities. 

06/11/07 IN-07-20 Use of Blank Ammunition All power reactors, Category I fuel cycle 

facilities, independent spent fuel storage 

installations, conversion facility, and 

gaseous diffusion plants. 
Enclosure 

IN 2007-35 

Page 3 of 3 

Date GC No. Subject Addressees 

07/19/07 IN-07-25 Suggestions from the Advisory 

Committee on the Medical Use of 

Isotopes For Consideration to 

Improve Compliance With Sodium 

Iodide I-131 Written Directive 

Requirements in 10 CFR 35.40 and 

Supervision Requirements in 10 

CFR 35.27 

All U.S. Nuclear Regulatory Commission 

(NRC) medical-use licensees and NRC 

Master Materials Licensees. All Agreement 

State Radiation Control Program Directors 

and State Liaison Officers. 

08/08/07 IN-07-23 Inadvertent Discharge of Halon 

1301Fire-suppression System from 

Incorrect and/or Out-of-date 

Procedures 

All holders of operating licenses for nuclear 

power reactors, except those who have 

permanently ended operations and have 

certified that fuel has been permanently 

removed from the reactor vessel. All 

holders of licenses for fuel cycle facilities. 

08/13/07 IN-07-26 Combustibility of Epoxy Floor 

Coatings at Commercial Nuclear 

Power Plants 

All holders of operating licenses for nuclear 

power reactors and fuel cycle facilities 

except licensees for reactors that have 

permanently ceased operations and who 

have certified that fuel has been 

permanently removed from the reactor 

vessel. 

09/13/07 IN-07-30 Radiological Controls Create 

Criticality Safety Accident Scenario 

for Fissile Solution Container 

Transport at Fuel Cycle Facility 

All licensees authorized to possess a 

critical mass of special nuclear material. 

09/28/07 IN-07-33 Exposures To Members Of The 

Public Caused By Inadequate 

Controls Over Well Logging 

Sources 

All U.S. Nuclear Regulatory Commission 

Well Logging Licensees. All Agreement 

State Radiation Control Program Directors 

and State Liaison Officers. 

03/01/07 RIS-07-03 Ionizing Radiation Warning Symbol All U.S. Nuclear Regulatory Commission 

licensees and certificate holders. All 

Radiation Control Program Directors and 

State Liaison Officers 

03/09/07 RIS-07-04 Personally Identifiable Information 

Submitted to the U.S. Nuclear 

Regulatory Commission 

All holders of operating licenses for nuclear 

power reactors and holders of and 

applicants for certificates for reactor 

designs. All licensees, certificate holders, 

applicants, and other entities subject to 

regulation by the U.S. Nuclear Regulatory 

Commission of the use of source, 

byproduct, and special nuclear material 

03/20/07 RIS-07-05 Status and Plans for Implementation 

of NRC Regulatory Authority for 

Certain Naturally-occurring and 

Accelerator-produced Radioactive 

Material 

All NRC materials licensees, Radiation 

Control Program Directors, State Liaison 

Officers, and NRC’s Advisory Committee 

on the Medical Uses of Isotopes

04/05/07 RIS-07-07 Clarification of Increased Controls 

for Licensees That Possess 

Collocated Radioactive Material 

During Transportation Activities 

All U.S. Nuclear Regulatory Commission 

(NRC) licensees issued NRC’s Order 

Imposing Increased Controls and all 

Radiation Control Program Directors and 

State Liaison Officers 
Enclosure 

IN 2007-35 

Page 3 of 3 

Date GC No. Subject Addressees 

05/04/07 RIS-07-09 Examples of Recurring Requests for 

Additional Information (RAIs) for 10 

CFR Part 71 and 72 Applications 

All holders of, and applicants for, a: (1) 10 

CFR Part 71 certificate of compliance 

(CoC) for a radioactive material 

transportation package; (2) 10 CFR Part 72 

CoC for a spent fuel storage cask; and (3) 

10 CFR Part 72 specific license for an 

independent spent fuel storage installation 

(ISFSI). 

06/27/07 RIS-06-27, 

Suppl. 1 

Availability of NRC 313A Series of 

Forms and Guidance for Their 

Completion 

All U.S. Nuclear Regulatory Commission 

(NRC) medical-use licensees and NRC 

Master Materials licensees. All Radiation 

Control Program Directors and State 

Liaison Officers. 

05/15/07 RIS-07-10 Subscriptions To New List Server 

For Automatic Notifications Of 

Medical-Related Generic 

Communications, Federal Register 

Notices And Newsletters 

All U.S. Nuclear Regulatory Commission 

(NRC) medical-use licensees and NRC 

Master Materials licensees. All Radiation 

Control Program Directors and State 

Liaison Officers. 

08/31/07 RIS-07-13 Verification of the Authenticity of 

Materials Possession Licenses 

All U.S. Nuclear Regulatory Commission 

materials licensees. All Agreement State 

Radiation Control Program Directors and 

State Liaison Officers. 

09/07/07 RIS-07-18 Data for Updating the Interim 

Inventory of Radioactive Sources 

All U.S. Nuclear Regulatory Commission 

(NRC) Part 40, Part 50, Part 70, Part 72, 

and Part 76 licensees and certificate 

holders who are authorized to possess 

sources of radioactive material 

at the Category “3.5" (as defined below) 

activity or higher. 

10/04/07 RIS-07-23 Date For Operation Of National 

Source Tracking System 

All licensees authorized to possess 

Category 1 or Category 2 quantities of 

radioactive materials. 

All Radiation Control Program Directors 

and State Liaison Officers. 

Note: A full listing of generic communications may be viewed at the NRC public website at the following address: 

http://www.nrc.gov/Electronic Reading Room/Document Collections/Generic Communications