Information Notice 1990-59, Errors in Use of Radioactive Iodine-131
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR MATERIALS SAFETY AND SAFEGUARDS
WASHINGTON, D.C.
20555
September 17, 1990
NRC INFORMATION NOTICE NO. 90-59:
ERRORS IN THE USE OF RADIOACTIVE IODINE-131
Addressees
All medical licensees.
Purpose
This information notice is intended to emphasize to medical use licensees the
potential radiation dose levels resulting from errors in the administration
of iodine-131 to humans.
This issue was previously addressed in IE Information
Notice No. 85-61, Suppliment 1: Misadministrations To Patients Undergoing
Thyroid Scans (attached). Due to the significance and frequency of recurrence
of these errors, NRC believes this issue should be readdressed. It is expected
that licensees will review this information for application to their own procedures
for the administration of iodine-131, distribute the notice to those responsible
for radiation safety and quality assurance, and consider actions, if appropriate, to establish procedures to preclude the misadministration of iodine-131 at their
facilities. However, suggestions contained in this notice do not constitute any
new U.S. Nuclear Regulatory Commission (NRC) requirements, and no written
response is required.
Description of Circumstances
The following cases are recent events reported to NRC that have resulted in
unintended radiation doses to humans, as a result of the administration of
radioactive iodine:
Case 1: A patient with a history of thyroid cancer was scheduled for her
yearly whole-body scan. Before the scan, the patient underwent a pregnancy
test, with negative results. After the pregnancy test results were received, the technologist began to complete a departmental questionnaire to obtain
information from the patient relative to the requested procedure. The
questionnaire addressed the possibilities of pregnancy and lactation. However, before completing the questionnaire, the technologist was called away and did
not return to complete the form before administration of the iodine-131. As
a result, the patient was given the intended dosage of 4.89 millicuries of
iodine-131. Approximately 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> later when the patient was scanned, there
was considerable iodine-131 uptake in her breasts. When questioned by the
physician, the patient indicated that she had given birth to a female infant
two weeks earlier and had been nursing this infant for approximately the last
36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The total body dose to the infant was estimated to be 17 rads, and the radiation dose to the infant's thyroid was estimated to be 30,000
rads. A synthetic thyroid hormone replacement has been prescribed for the
child, with scheduled periodic follow-ups. The unintended dose to the mother's
breasts was estimated to be 8.9 rads.
> 920156 Z J
4
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IN 90-59 September 17, 1990 Case 2: A patient to be scheduled for a thyroid scan was administered 3 millicuries of iodine-131 instead of the intended dosage of 300 microcuries of
The patient's physician called in the request for a thyroid scan
to the secretary of the nuclear medicine department, who inadvertently
scheduled a whole-body scan.
No written request from the physician was
required. The dosage at this facility for a whole-body scan is 3 millicuries
of iodine-131, whereas the dosage for a thyroid scan is 300 microcuries of
iodine-123. The estimated dose to the patient's thyroid gland due to this
error was 4700 rads.
Case 3: A patient was scheduled for an ectopic thyroid evaluation, with an
intended dosage of 100 microcuries of iodine-131. In completing the Nuclear
Medicine department referral sheet, the referring physician incorrectly
requested a post-thyroidectomy neck scan.
As a result, the patient was
administered 1 millicurie of iodine-131, with an estimated dose to the
thyroid of 1300 rads.
Case 4: A patient was scheduled for an ectopic thyroid evaluation, with an
Intended dosage of 50 to 100 microcuries of iodine-131. The technologist
consulted the department procedure manual that listed prescribed dosages for
specific scans, and the dosage was incorrectly listed as 4.5 millicuries. As a
'result, the patient was administered 4.3 millicuries. The estimated dose'to
this patient's thyroid gland was 4300 rads.
Case 5: A patient was administered a dosage of 15 microcuries of iodine-131.
Almost immediately following the administration, the patient indicated to the
technologist that she was approximately 4 to 5 weeks pregnant.. The technologist
failed to ask the patient if she was pregnant before the administration. The
patient had arrived at the department with a baby in her arms, and the
technologist assumed that the patient was not pregnant. The total body dose to
the fetus was estimated to be 2 to 4 millirem. Since the fetal thyroid is
incapable of concentrating iodine-131 until approximately 12 weeks of gestation, it was estimated that there was no additional dose to the fetal thyroid.
DISCUSSION
All licensees are reminded of the importance of ensuring the safe performance
of licensed activities, in accordance with NRC regulations, requirements of
their licenses, and accepted medical practice. The forementioned cases
illustrate:
the lack of familiarity with appropriate thyroid studies and
dosages; the necessity of consistently following quality control procedures;
and a need to understand the significance of radiation doses that result -
from the administration of millicuries versus microcuries of radiopharmaceuticals
containing radioiodine.
Specifically, the radiation dose to the thyroid, resulting from a dosage of one millicurie rather than one microcurie of
j
.
IN 90-59 September 17, 1990 iodine-131, is a one thousand-fold increase. In addition, the radiation dose
received from an activity of iodine-131 is approximately-100 fold greater than
the dose from the same activity of iodine-123. The following table illustrates
the relationship between microcurie versus millicurie quantities of iodine-131, as well as the radiation dose differential between iodine-123 and iodine-131, for three different age groups, with a thyroid uptake of 15 percent.
TABLE:
1 year
5 years
Adult
A Comparison of IsQtopes and'Radiation Doses for
Various Age Groups Assuming 15% Uptake by the Thyroid*
Rads per uqi
Rads per mCi
1-131 I-123
1-131 old
0.07
7.40
70.3
7400
old
0.04
4.07
40.0
4070
0.007
0.78
7.0
777
.
.
.
- Based on information from ICRP-Publication No. 53 All workers should have a clear understanding of the significance of errors.in
scale when calculating and preparing diagnostic dosages versus therapeutic
dosages of radiopharmaceuticals containing radioiodine. The threshold at which
a diagnostic dosage becomes a therapeutic dosage is low, and depends on the age
of the patient and the percent uptake by the patient's thyroid gland.
Consequently, the potential for causing a significant, undesired radiation
dose to a patient's thyroid gland must always be kept in mind when administering
iodine radiopharmaceuticals.
Licensees are reminded that the package inserts provided by the manufacturers
contain information pertinent to both proper dosages and radiation doses, and may be valuable resources when reviewing imaging policies and procedures
for errors and inconsistencies. Nuclear medicine department procedures should
include provisions for questioning female patients about the possibility of
pregnancy or lactation. By attention to detail, and adherence to departmental
policy and procedures, many incidents involving radioactive iodine-131 may be
avoided.
r- IN 90-59 September 17, 1990 No specific written response is required by this information notice.
If you
have any questions regarding this matter, please contact the appropriate regional
office or this office.
M
r Cunnnhm, ro
Division of Industrial and
Medical Nuclear Safety
Office of Nuclear Material Safety
and Safeguards
Technical Contact:
Sally Merchant, NMSS
(301) 492-0637- Attachments:
1. List of Recently Issued NMSS
Information Notices.
2. List of Recently Issued NRC
Information Notices.
Attachment 1
September 17, 1990 LIST OF RECENTLY ISSUED
HMSS INFORMATION NOTICES
Information
Date of
Notice No.
Subject
Issuance
Issued to:
90-50
Minimization of Methane Gas
in Plant Systems and Radwaste
Shipping Containers
08/08/90
All holders
licenses or
permits for
reactors
of operating
construction
nuclear power
90-44 Dose-Rate Instruments
06/29/90
90-38 Requirements for Processing
05/29/90
Financial Assurance Submittals
for Decommissioning
90-35
Transportation of Type A
-
Quantities of Non-Fissile
Radioactive Materials
90-31
Update on Waste Form and
High Integrity Container
Topical Report Review Status,
Identification of Problems
with Cement Solidication, and
Reporting of Waste Mishaps
90-27
Clarification of the
Recent Revisions to the
Regulatory Requirements
for Packaging of Uranium
Hexafluoride (UF6 ) for
Transportation
90-24
Transportation of Model
SPEC 2-T Radiographic
Exposure Device
90-20
Personnel Injuries
Resulting from Improper
Operation of Radwaste
Incinerators
05/24/90
05/04/90
04/30/90
04/10/90
03/22/90
All NRC licensees
All fuel facility
and materials
All U.S. Nuclear
Regulatory Commission
(NRC) Licensees
All holders of operating
licenses or construction
permits for nuclear power
reactors, fuel cycle
licenses, and certain
byproduct materials
licenses
All Uranium Fuel
Fabrication and Conversion
Facilities
All NRC licensees
authorized to use, transport, or operate
radiographic exposure
devices and source
changers
All NRC licensees
who process or incinerate
radioactive waste
- -
Attachment 2
-
IN-90-59 !
September 17, 1990
. LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information
Date of
Notice No.
Subject
Issuance
Issued to
90-58
90-57
90-56
90-55
83-44 Supp. 1
Improper Handling of
Ophthalmic Strontium-90
Beta Radiation Applicators
Substandard, Refurbished
Potter & Brumfield Relays
Misrepresented As New
Inadvertent Shipment of A
Radioactive Source In A
Container Thought To Be
Empty
Recent Operating Experi- ence on Loss of Reactor
Coolant Inventory While
In A Shutdown Condition
Potential Damage to
Redundant Safety Equip- ment As A Result of
Backflow Through the
Equipment and Floor Drain
System
Summary of Requalification
Program Deficiencies
Criminal Prosecution of
Wrongdoing Committed by
Suppliers of Nuclear
Products or Services
Potential Failures of
Auxiliary Steam Piping and
the Possible Effects on the
Operability of Vital Equip- ment
9/11/90
9/5/90
9/4/90
8/31/90
8/30/90
8/28/90
8/24/90
8/16/90
All NRC medical
licensees.
All holders of OLs
or CPs for nuclear
power reactors.
All U.S. Nuclear
Regulatory Com- mission (NRC)
licensees.
All holders of OLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPs for nuclear
power reactors.
All holders of GLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPs for nuclear
power reactors.
90-54
89-18 Supp. 1
90-53 OL = Operating License
CP = Construction Permit
IN 90-
September ,1990 No specific written response is required by this information notice. If you
have any questions regarding this matter, please contact the appropriate
regional office or this office.
~4M zlgned #1
Richard Cunningham, Director
Division of Industrial and
Medical Nuclear Safety
Office of Nuclear Material Safety
and Safeguards
Technical Contact:
Sally Merchant, NMSS
(301) 492-0637 Attachments:
1. List of Recently Issued NMSS
Information Notices.
2. List of Recently Issued NRC
Information Notices.
E. Kraus/Tech. Ed.
8/21/90
1311