UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF FEDERAL AND STATE MATERIAL AND

ENVIRONMENTAL MANAGEMENT PROGRAMS

WASHINGTON, D.C. 20555-0001

July 19, 2007

NRC INFORMATION NOTICE 2007-25: 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

ADDRESSEES

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.

PURPOSE

The U.S. Nuclear Regulatory Commission (NRC) is issuing this Information Notice (IN) to

underscore the requirement in 10 CFR 35.40 that the administration of sodium iodide

iodine-131 (I-131) in dosages greater than 1.11 megabecquerels (MBq) (30 microcuries (μCi))

requires a written directive signed and dated by an authorized user (AU). In this connection,

this IN is being issued to emphasize the need for administering technologists to verify the

existence of written directive and/or the dosage with an AU prior to administration of sodium

Iodide I-131. Another purpose of the IN is to remind licensees of their responsibility under 10

CFR 35.27(a) to instruct the supervised individual in written directive procedures and to require

supervised individuals to follow the instruction of the supervising AU. This IN contains the

Advisory Committee on the Medical Use of Isotopes’ (ACMUI’s) suggestions for ensuring

compliance in using written directives and improving communication between the AU and the

individual performing the administration. Recipients should review the information contained in

this IN for applicability to their facilities and consider actions, as appropriate. 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 licensees as appropriate.

BACKGROUND

Between February, 2004, and May, 2005, NRC received eleven medical event reports involving

oral administrations of sodium iodide I-131 at activity levels that required written directives. The

NRC requested that the ACMUI examine these medical events identify root causes and ways of

reducing the occurrence of these types of medical events. In April, 2006, the ACMUI,

presented NRC with its conclusions and recommendations. The NRC incorporated the ACMUI

recommendations in this IN for distribution and consideration by the medical community. 
IN 2007-25

Page 2 of 5

The dosage activity in seven of the eleven sodium iodide I-131 administrations exceeded the

minimum dosage activity that required a written directive (i.e., greater than 1.11 MBq (30 μCi)),

but a written directive had not been issued. Nine of the medical events resulted in overdosages. 

Although the details of the medical events varied, the primary cause for most of the events was

the licensee’s failure to verify all sodium iodide I-131 dosages greater than 30 μCi against a

written directive prior to administration.

The NRC notes that there is evidence that this failure continues to be a cause for medical

events. Specifically, since the ACMUI performed its review, there have been 8 additional

medical events involving sodium iodide I-131 (not included in the examples below) that also

involved the failure to verify that there was a written directive for sodium iodide I-131 dosages

greater than 30 μCi. These additional events underscore the continuing need to increase

awareness of the written directive requirements in 10 CFR 35.40 and corresponding supervision

requirements in 10 CFR 35.27(a).

DESCRIPTION OF CIRCUMSTANCES

There were no written directives for eight of the eleven administrations reviewed by the ACMUI,

because five prescribed dosages were for less than 30 μCi of sodium iodide I-131 (two of these

included verbal orders), one was for a different radionuclide (I-123), one had no prescribed

dosage, and one for greater than 30 μCi was only made verbally. The absence of written

directives for sodium iodide I-131 dosages greater than 30 μCi should have alerted the

administering technologist to seek a written directive and, if one was not found, to verify the

dosage with the AU prior to administration.

The three remaining medical events involved written directives which were not followed. These

three events were primarily due to human errors (i.e., lack of attention to detail and failure to

follow procedures) compounded by the staff’s failure to follow a written directive. Reviewing the

written directive or contacting the AUs prior to administering the dosages could have prevented

these errors. 

Cases in which No Written Directive was issued - Eight Cases:

Pharmacy Errors

P A contaminated pipette in the radiopharmacy raised the desired dosage of 20 μCi, to 0.9

millicurie (mCi). The dosage was correctly labeled as 0.9 mCi. The activity displayed

on the radiopharmacy dose calibrator of “0.915 mCi” was misinterpreted by the

radiopharmacy technologist as “9.15 μCi.” The nuclear medicine technologist misread

the 0.9 mCi on the label as 9 μCi and administered the dosage. This resulted in an

administered dosage of 915 μCi rather than the requested dosage of 5 to 20 μCi. 

P The radiopharmacy prepared a dosage of 980 μCi instead of the prescribed dosage of

15 μCi. The dosage of 980 μCi was administered to a patient by a technologist at the

medical facility without verification of the dosage. This mistake could have been
IN 2007-25

Page 3 of 5

prevented by verifying the dosage and recognizing that a written directive is required for

all sodium iodide I-131 administrations exceeding 30 μCi.

Pharmacy Error Compounded by a Verbal Order

P The AU gave a verbal order for 2.0 mCi without providing the required written directive. 

The nuclear pharmacy inadvertently prepared and sent a 2.8 mCi dosage, which was

then administered by the technologist at the medical facility.

Verbal Order

P The technologist misunderstood the verbal orders of the AU and ordered 500 μCi of

sodium iodide I-131 instead of 5 μCi. The patient was administered 535 μCi instead of

the intended 5 μCi. The technologist did not verify the existence of a written directive,

which is required for all sodium iodide I-131 administrations exceeding 30 μCi.

Misunderstood request/written order

P The technologist misunderstood the referring physician’s request (the report does not

specify the form of the request) and administered 3 mCi of sodium iodide I-131 rather

than the intended 25 μCi. Approval of the dosage was not obtained from the AU prior to

administration.

P The AU intended to prescribe 12 mCi but instead wrote 12 μCi by mistake on the

prescription. The technologist did not realize that the AU had written 12uCi and ordered

and administered a dose of 12mCi which the technologist thought was what the AU had

intended; however, this administration did not comply with the written directive, and

therefore constituted a medical event. This event was caused by the failure to compare

a dosage greater than 30 μCi with the AU’s written instruction and lack of

communication between the technologist and the AU.

Wrong Patient

P The individual received a 2 mCi I-131 dosage instead of the intended 200 μCi I-123

dosage because the patient incorrectly responded affirmatively to being the patient that

was supposed to receive the I-131 dosage.

No Order

P The technologist administered a 4 mCi dosage that was left over from a previous “no

show” patient without a written directive under the assumption that the prescribing

physician would complete the written directive at a later time. After administering the 4

mCi dosage, the technologist discovered that the AU had intended to prescribe

150 mCi. As there had been no written directive, the technologist could not verify the

prescribed dosage against the dosage about to be administered.

Failure to Follow a Written Directive - Three Cases:

 

P Two different medical events resulted in administered dosages of 5.2 mCi and 15 mCi

instead of the prescribed 2 mCi dosages. One was attributed to lack of attention to
IN 2007-25

Page 4 of 5

detail and the other to failure to follow procedures. 

P The technologist confused the dosages of three patients who were scheduled to receive

I-131 treatments on the same day and administered 100 mCi to a patient who was

scheduled to receive 17.3 mCi. 

DISCUSSION

As outlined in the DESCRIPTION OF CIRCUMSTANCES, most of the medical events were

caused primarily by failure to recognize that dosages greater than 30 μCi of sodium iodide I-131

require a written directive and should have been verified against a prescribed dosage in a

written directive. With the exception of the patient misidentification, these events could have

been preventable if procedures had been established and followed for checking dosages about

to be administered against a prescribed dosage contained in a written directive. The ACMUI

developed four suggestions that the medical community may consider to improve compliance

with the regulations.

1) Licensees are required to have a written directive before the administration of greater than

30 μCi of sodium iodide I-131 (10 CFR 35.40) and to provide instructions in written directive

procedures to supervised individuals (10 CFR 35.27). The ACMUI suggests that licensees

reemphasize these requirements to their staff so that the staff is aware that a written

directive is required for dosages of sodium iodide I-131 greater than 30 μCi and verifies that

there is a written directive before administering these dosages. Licensees also should

remind staff that verbal orders are only acceptable under specific situations and, even then,

must be followed up with a written directive (10 CFR 35.40(a)(1) and 35.40(c)(1)).

2) Licensees are required to determine and record the activity of each dosage before medical

use (10 CFR 35.63). The ACMUI recognizes that licensees are not required to perform a

direct measurement of a unit dosage in a dose calibrator prior to administration, if it is

received from a drug manufacturer or commercial nuclear pharmacy. However, the ACMUI

believes that it is a good standard of practice to make direct measurements of therapeutic

dosages in dose calibrators. The ACMUI also suggests that licensees have the written

directive readily available while determining the dosage prior to administration to verify and

ensure that the dosage to be administered conforms with the written directive.

3) The licensee is required to have written procedures to provide high confidence that the

patient’s identity is verified before each administration (10 CFR 35.41(a)(1)). The ACMUI

suggests that licensees evaluate their identity verification procedures to prevent patient

misidentification. Although not required by the regulations, the ACMUI suggests that

licensees consider confirming positive patient identification by two separate methods prior to

dosage administration. The ACMUI suggests following a patient identification procedure

similar to that required for a blood administration.

4) The ACMUI suggests that licensees seek to improve communication between AUs and the

individuals performing the administration. The AUs should consider reviewing plans for the

treatment with the administering technologists. In addition, licensee management should

foster a culture at the licensee’s facility that encourages technologists to freely ask

questions of the AUs regarding written directives.
IN 2007-25

Page 5 of 5

NRC licensees must ensure that their staff fully understand and adhere to the requirements

contained in the regulations. NRC, in coordination with the ACMUI, has developed this IN to

convey the above suggestions drawn from a study of medical events involving the oral

administration of sodium iodide I-131. Unless specifically addressed in 10 CFR Part 35, these

suggestions are not NRC requirements. The ACMUI believes consideration of these

suggestions will improve compliance with the regulations and minimize the likelihood of medical

events.

CONTACT

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

information in this notice, please notify the technical contact listed below or the appropriate

regional office.

 /RA/

Janet R. Schlueter, Director

Division of Materials 

 and State Agreements

Office of Federal and State Materials 

 and Environmental Management Programs

Technical Contact: Donna-Beth Howe, PhD, FSME

(301) 415-7848

dbh@nrc.gov

Enclosure:

“List of Recently Issued FSME/NMSS 

 Generic Communications”
IN 2007-25

 Page 5 of 5

convey the above suggestions drawn from a study of medical events involving the oral

administration of sodium iodide I-131. Unless specifically addressed in 10 CFR Part 35, these

suggestions are not NRC requirements. The ACMUI believes consideration of these

suggestions will improve compliance with the regulations and minimize the likelihood of medical

events.

CONTACT

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

information in this notice, please notify the technical contact 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: Donna-Beth Howe, PhD, FSME

(301) 415-7848

dbh@nrc.gov

Enclosure: 

“List of Recently Issued FSME/NMSS 

 Generic Communications”

DISTRIBUTION:

FSME/ r/f Regional Administrators DBHowe

ML062060013 

OFFICE MSEA MSEA MSEA OGC TechEd MSEA MSA/FSME

NAME DBHowe CFlannery SWastler FCameron CPoland AMcIntosh JSchlueter

5/ 18 /07 5/ 18 /07 5/ 22 /07 7/ 5 /07 / /07 6 / 07 /07 7 / 6 /07

OFFICIAL RECORD COPY
Enclosure 

IN 2007-25

Page 1 of 3

Recently Issued FSME/NMSS Generic Communications

Date GC No. Subject Addressees

12/7/06 RIS-06-26 TRAINING AND EXPERIENCE

AND GRANDFATHER

PROVISIONS FOR AUTHORIZED

MEDICAL PHYSICISTS UNDER

10 CFR PART 35

All NRC medical licensees and Radiation

Control Program Directors.

12/7/06 RIS-06-25 Requirements For The Distribution

And Possession Of Tritium Exit

Signs And The Requirements In 10

CFR 31.5 AND 32.51a

All U.S. Nuclear Regulatory Commission

(NRC) licensees distributing tritium exit

signs and those possessing a tritium exit

sign under a general license.

11/15/06 RIS-06-22 Lessons Learned From Recent 10

CFR PART 72 Dry Cask Storage

Campaign

All Title 10 Code of Federal Regulations

(10 CFR) Part 72 specific licensees and

certificate holders and holders of

operating licenses for nuclear power

reactors (including those who have

permanently ceased operations and have

certified that fuel has been permanently

removed from the reactor vessel) that are

not 10 CFR Part 72 specific licensees.

09/22/06 RIS-06-14 Enforcement Discretion for Facility

Changes Under 10 CFR

70.72(c)(2)

All fuel cycle licensees regulated under

Title 10 of the Code of Federal

Regulations (10 CFR) Part 70, Subpart H.

09/14/06 RIS-06-20 Guidance for Receiving

Enforcement Discretion When

Concentrating Uranium at

Community Water Systems

All community water systems (CWSs), in

U.S. Nuclear Regulatory Commission

(NRC) non-Agreement States, that during

the treatment of drinking water, may

accumulate and concentrate naturallyoccurring uranium in media, effluents,

and other residuals, above 0.05 percent

by weight.

09/14/06 RIS-06-19 Availability of Guidance on

Radioactive Seed Localization

All NRC medical licensees.

08/31/06 RIS-06-18 Requesting Exemption from the

Public Dose Limits for Certain

Caregivers of Hospital Patients

All NRC medical licensees.

08/15/06 RIS-06-16 Transfer of the Management

Oversight Of Certain NRC Region I

Licensees in Mississippi 

To the NRC Region IV Office

All NRC materials licensees.

07/20/06 RIS-06-11 Requesting Quality Assurance

Program Approval Renewals

Online by Electronic Information

Exchange 

All 10 CFR Part 71 quality assurance

program and certificate holders.

04/23/06 RIS-06-10 Use of Concentration Control for

Criticality Safety

All licensees authorized to possess a

critical mass of special nuclear material.
Enclosure 

IN 2007-25

Page 2 of 3

Date GC No. Subject Addressees

01/26/06 RIS-02-15,

Rev. 1

NRC Approval of Commercial Data

Encryption Products For the

Electronic Transmission Of

Safeguards Information

All authorized recipients and holders of

sensitive unclassified safeguards

information (SGI).

01/24/06 RIS-06-01 Expiration Date for NRC-Approved

Spent Fuel Transportation Routes

The U.S. Nuclear Regulatory Commission

(NRC) licensees who transport, or deliver

to a carrier for transport, irradiated

reactor fuel (spent nuclear fuel (SNF)).

01/13/06 RIS-05-27,

Rev. 1

NRC Timeliness Goals,

Prioritization of Incoming License

Applications and Voluntary

Submittal of Schedule for Future

Actions for NRC Review

All 10 CFR Parts 71 and 72 licensees

and certificate holders.

11/14/06 IN-06-25 Lessons Learned From NRC

Inspection Of Control And

Accounting Of Special Nuclear

Material At Commercial Nuclear

Power Reactors

All power reactors, category I fuel cycle

facilities, independent spent fuel storage

installations, conversion facility, and

gaseous diffusion plants. Note that the

information notice contains physical

security information and is, therefore,

being withheld from public disclosure in

accordance with 10 CFR 2.390

11/7/06 IN-06-23 Events Involving Potential

Tampering Or Malfeasance By

Persons Granted Unescorted

Access

All power reactors, category I fuel cycle

facilities, independent spent fuel storage

installations, conversion facility, and

gaseous diffusion plants. Note that the

information notice contains physical

security information and is, therefore,

being withheld from public disclosure in

accordance with 10 CFR 2.390

07/10/06 IN-06-13 Ground-Water Contamination

Due to Undetected Leakage of

Radioactive Water

All holders of operating licenses for

nuclear power and research and test

reactors including those who have

permanently ceased operations and

have certified that fuel has been

permanently removed from the

reactor and those authorized by Title

10 of the Code of Federal Regulations

(10 CFR) Part 72 licenses to store

spent fuel in water-filled structures.

07/06/06 IN-06-12 Exercising Due Diligence When

Transferring Radioactive

Materials

All materials licensees.

06/12/06 IN-06-11 Applicability of Patient Intervention

in Determining Medical Events for

Gamma Stereotactic Radiosurgery

and Other Therapy Procedures

All medical licensees.

03/31/06 IN-06-07 Inappropriate Use of a Singleparameter Limit as a Nuclear

Criticality Safety Limit

All licensees authorized to possess a

critical mass of special nuclear material.
Enclosure 

IN 2007-25

Page 3 of 3

Date GC No. Subject Addressees

03/21/06 IN-02-23,

Supl. 1

Unauthorized Administration of

Byproduct Material for Medical Use

All medical licensees.

01/19/06 IN-06-02 Use of Galvanized Supports and

Cable Trays with Meggitt Si 2400

Stainless- Steel-jacketed Electrical

Cables

All holders of operating licenses for

nuclear reactors except those who have

permanently ceased operations and have

certified that fuel has been permanently

removed from the reactor vessel; and fuel

cycle licensees and certificate holders.

Note: NRC generic communications may be found on the NRC public website at http://www.nrc.gov, under Electronic