Information Notice 2021-02, Recent Issues Associated with Monitoring Occupational Exposure to Radiation from Licensed and Unlicensed Radiation Sources

Recent Issues Associated with Monitoring Occupational Exposure to Radiation from Licensed and Unlicensed Radiation Sources

ML21152A239
Person / Time
Issue date:	08/04/2021
From:	Chris Miller, Kevin Williams Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation
To:
Benney B
References
IN-21-002
Download: ML21152A239 (7)

ML21152A239 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS

WASHINGTON, DC 20555-0001

August 4, 2021

NRC INFORMATION NOTICE 2021-02: RECENT ISSUES ASSOCIATED WITH

MONITORING OCCUPATIONAL EXPOSURE

TO RADIATION FROM LICENSED AND

UNLICENSED RADIATION SOURCES

ADDRESSEES

All U.S. Nuclear Regulatory Commission (NRC) materials licensees. All Radiation Control

Program Directors and State Liaison Officers.

PURPOSE

The NRC is issuing this information notice (IN) to inform addressees of recent issues

associated with monitoring occupational exposure to radiation from licensed and unlicensed

radiation sources under the licensees control. The NRC expects that recipients will review

the information for applicability to their facilities and consider actions, as appropriate, to

avoid similar problems. Any suggestions contained in the IN are not new NRC

requirements; therefore, no specific action or written response is required. The NRC is

providing this IN to the Agreement States for their information and for distribution to their

licensees as appropriate.

DESCRIPTION OF CIRCUMSTANCES

From August 2018 to October 2020, the NRC identified issues at seven NRC medical-use

licensees involving compliance issues associated with monitoring individuals occupational

exposure to radiation from licensed and unlicensed radiation sources that were under the

control of the licensees. The issues were associated with occupational radiation exposures

received by interventional radiology (IR) physicians who were involved in the conduct of

NRC-licensed activities under the provisions of 10 CFR 35.1000, Other medical uses of

byproduct material or radiation from byproduct material. Although the issues described in

this IN were identified at NRC medical-use licensees, the information provided is applicable

to all NRC licensees where occupational radiation exposures from licensed and unlicensed

radiation sources can occur.

Monitoring Exposure to Unlicensed Radiation Sources Under Licensee Control

The IR physicians performed activities involving the administration of yttrium-90

microspheres, which is an NRC-licensed radioactive byproduct material. Additionally, the IR

physicians were exposed to unlicensed radiation sources. Unlicensed radiation sources are

not licensed by the NRC and include radiation from certain radiation-producing devices, such as fluoroscopy equipment and other x-ray-generating devices. Although not licensed

by the NRC, these sources of radiation may be subject to registration with state regulatory

agencies. Specifically, at the seven NRC medical-use licensees, IR physicians used fluoroscopic

(x-ray) guidance to place an intraarterial microcatheter to the targeted delivery area for the

yttrium-90 microspheres. The IR physicians who administered the yttrium-90 microspheres

also performed numerous other IR procedures using fluoroscopic guidance that did not

involve the use of NRC-licensed radiation sources.

During NRC inspections at the medical-use licensees, the NRC identified several issues, including licensees understanding of the NRC regulatory requirement in

10 CFR 20.1502(a). This regulation requires that each licensee monitor exposure to

radiation and radioactive material at levels sufficient to demonstrate compliance with the

occupational dose limits specified in 10 CFR Part 20, Standards for protection against

radiation. In accordance with 10 CFR 20.1502, Conditions requiring individual monitoring

of external and internal occupational dose, requires monitoring of exposure to licensed and

unlicensed radiation sources under the control of the licensee:

As a minimum, each licensee shall monitor occupational exposure to radiation

from licensed and unlicensed radiation sources under the control of the licensee

and shall supply and require the use of individual monitoring devices by

(1) Adults likely to receive, in 1 year from sources external to the body, a dose in

excess of 10 percent of the limits in 10 CFR 20.1201(a); (2) Minors likely to

receive, in 1 year, from radiation sources external to the body, a deep dose

equivalent in excess of 0.1 rem (1 mSv), a lens dose equivalent in excess of

0.15 rem (1.5 mSv), or a shallow dose equivalent to the skin or to the extremities

in excess of 0.5 rem (5 mSv); (3) Declared pregnant women likely to receive

during the entire pregnancy, from radiation sources external to the body, a deep

dose equivalent in excess of 0.1 rem (1 mSv); and (4) Individuals entering a high

or very high radiation area.

The NRC observed that some IR physicians wore assigned individual monitoring devices

(personnel dosimeters) inconsistently. For example, some IR physicians wore the assigned

personnel dosimeter only during yttrium-90 procedures, but not during IR procedures that

did not involve yttrium-90, under the misunderstanding that their exposure to unlicensed

x-ray sources was not required to be monitored. The inspectors also observed that some IR

physicians did not wear assigned personnel dosimeters at all when working with either

licensed or unlicensed radiation sources.

In accordance with 10 CFR 20.1101(a), licensees are required to develop, document, and

implement radiation protection programs commensurate with the scope and extent of

licensed activities and sufficient to ensure compliance with the provisions of 10 CFR Part 20,

Standards for protection against radiation. NRC inspectors found that licensees radiation

protection programs, specifically their policies and procedures for occupational dosimetry

programs, often did not have provisions to address 10 CFR 20.1201(f) and 10 CFR 20.2104, Determination of prior occupational dose. As a result, licensees did not account for

occupational radiation exposure received by individuals either: (1) concurrently while

employed at other facilities, including other NRC-licensed facilities, Agreement

State-licensed facilities, or unlicensed facilities, or (2) during the same calendar year, prior to

the individual performing licensed activities under the licensees control. Consequently, licensees were not cognizant of the total radiation dose received by those individuals and

whether this additional occupational dose would result in any radiation doses in excess of

the NRCs regulatory limits. Improper Use and Implementation of Dosimetry Approaches

The NRC found that the proper use of personnel dosimeters varied significantly among IR

physicians. In some cases, IR physicians wore their personnel dosimeter improperly, which

included not wearing the personnel dosimeter in the assigned location in accordance with

licensees policies (e.g., collar vs. waist, or above lead shielding vs. under lead shielding).

At one licensee, personnel dosimeters not being worn were stored improperly in a radiation

area. Several IR physicians did not exchange assigned personnel dosimeters at the

indicated frequency or often wore them significantly beyond the monitoring period indicated

on the dosimeter.

Dosimetry vendors often offer single- and double-dosimeter approaches with correction

factors to take nonuniform radiation exposures into account, such as those occupational

exposures received when wearing a lead apron during the performance of IR procedures.

Some licensees did not establish policies or procedures to address the dosimetry approach

used.

As a result, licensees inconsistently applied correction factors, which most often occurred

with double-dosimeter approaches. Double-dosimeter approaches typically rely on one

dosimeter to be worn at the collar outside of the lead, and one dosimeter to be worn at the

waist under the lead. Licensees that used a double-dosimeter approach often did not have

policies and procedures that addressed issues that would reasonably be expected to arise

from this dosimetry approach. For example, licensees did not have policies or procedures

for actions to be taken if one or both assigned personnel dosimeters were not turned in for

processing at the end of the assigned wear period. Licensees policies often did not

address actions to be taken if the personnel dosimeters were not worn at the assigned

location, such as if the waist dosimeter were worn at the collar outside of the lead. The NRC

observed that when this occurred, the licensee-assigned radiation exposures were often

higher, and in some cases grossly higher, than those that would have been expected for the

individual IR physician caseload.

Radiation Safety Programs: Training and Oversight

The NRC also identified various deficiencies regarding licensees implementation and

oversight of their radiation safety programs. These included deficiencies in licensees

radiation safety program content and implementation and their training programs.

Licensees also did not implement corrective actions to address identified personnel

dosimetry issues.

In the area of licensees radiation safety program content and implementation, the

inspectors found that licensees did not comply with 10 CFR 20.1101(a), which requires that

licensees develop, document, and implement radiation protection programs that are

commensurate with the scope and extent of licensed activities and sufficient to assure

compliance with 10 CFR Part 20. For several of the medical-use licensees involved in these

cases, the NRC found that the licensees radiation safety policies and procedures did not

adequately describe their personnel dosimetry program or to require the use of individual

monitoring devices.

In some cases, through routine audit and oversight activities, licensees or their third-party

auditors identified issues with individuals not wearing, or improperly wearing, their assigned

personnel dosimeters. However, when issues were identified, licensees either did not investigate these matters and implement corrective actions, or the corrective actions that

they implemented were not sufficient to correct the issues and prevent recurrence.

Although the NRC found most licensees policies and procedures for occupational dosimetry

programs to have established thresholds to identify unusually high radiation exposures, the

licensees did not to establish mechanisms to identify occupational radiation exposure values

that were unusually lower than expected, or where no results were reported. For example, several IR physicians performed over 100 IR procedures a month, but their monthly

personnel dosimeter reading was less than 1 millirem. It is unlikely that the performance of

over 100 IR procedures in 1 month would result in little to no measurable radiation dose.

These licensees did not have mechanisms to identify or flag these unusually low dosimeter

readings for further review or investigation.

Some licensees performed routine reviews of dosimeter results and identified unusually high

radiation exposures for IR physicians. However, in many cases, the licensees did not

investigate the cause of these excessively high or anomalous dosimeter readings. In some

cases, the licensees investigations consisted of a written warning to the IR physicians, but

the licensees did not actually investigate or attempt to understand the causes of the high or

anomalous dosimeter readings. In one case, a licensee observed high dosimeter results for

an IR physician and investigated the matter. The licensee determined that the IR physician

was wearing the assigned dosimeter correctly, while the other IR physicians with lower

dosimeter results were not wearing their assigned dosimeters correctly. However, the

licensee took no corrective actions to address the noncompliant dosimeter use by the other

IR physicians.

Licensees also did not provide adequate instruction to individuals in accordance with

10 CFR 19.12, Instruction to workers. In all cases, the NRC found that the licensees

provided the IR physicians with personnel dosimeters, but the IR physicians rarely received

instruction or training in the licensees policies and procedures for dosimeter use. NRC

inspectors observed that some licensees assumed that IR physicians would already

possess such knowledge, based on their education and credentials, and that licensee- specific training was not required or necessary. Some licensees simply did not include IR

physicians in licensee training programs. This was observed to be more prevalent when the

IR physicians were contracted individuals or independent radiology providers rather than

licensee employees.

DISCUSSION

The NRC regulates the possession and use of radioactive byproduct material, special

nuclear material, and source material. Licensed radiation sources are byproduct material, special nuclear material, and source material that are (1) authorized by a specific license

issued by the NRC or (2) authorized under a general license as specified in the NRC

regulations. Unlicensed radiation sources are those radiation sources that are not licensed

by the NRC under a specific or general license. Unlicensed sources include radiation from

certain radiation-producing devices, such as fluoroscopy equipment and other x-ray- generating devices. These unlicensed sources of radiation may be subject to registration

with state regulatory agencies.

Although the NRC identified the issues described in this IN at its medical-use licensees,

10 CFR 20.1501(a) is applicable to all NRC licensees where occupational radiation

exposures from licensed and unlicensed radiation sources can occur. For example, some industrial radiography licensees use radiographic exposure devices with NRC-licensed

byproduct material radioactive sources, such as cobalt-60 and iridium-192, and also use

radiographic exposure devices that employ x-ray-generating sources, which are not licensed

by the NRC. If occupationally exposed individuals, such as industrial radiographers, use

byproduct material radioactive sources and x-ray-generating sources under the control of

the licensee, the licensee is required to monitor the occupational radiation exposures to

these individuals from both of these radiation sources.

In accordance with 10 CFR 20.1502(a), licensees are to supply and require the use of

individual monitoring devices for the specified categories of occupationally exposed

individuals. It is only through the proper use of these individual monitoring devices that

licensees can evaluate radiation doses to determine compliance with the NRCs

occupational dose limits.

The NRC identified compliance issues associated with the licensees occupational radiation

monitoring programs resulted in escalated enforcement action against several licensees and

required extensive licensee actions to correct the deficiencies. The licensees efforts

included significant revisions to licensees radiation safety programs, procedures and

policies, training programs, and oversight practices. Further, licensees corrective actions

included complex evaluations of radiation exposure data to determine radiation dose

estimates. Many of the licensees had to make radiation dose estimates for multiple IR

physicians for occupational radiation exposures that occurred over several years for

licensed and unlicensed radiation sources under the control of the licensees. Although

licensees radiation dose estimates resulted in no individual exceeding the NRCs

occupational dose limits specified in 10 CFR Part 20, several individuals closely approached

those limits.

The NRC expects that licensees will develop, implement, and maintain radiation protection

programs, including programs for monitoring occupational radiation exposures, that are

commensurate with the scope and extent of their activities, in accordance with

10 CFR 20.1101(a). NRC inspectors have found that effective licensee radiation protection

programs include policies and procedures associated with monitoring occupational radiation

exposures. NRC inspectors found that comprehensive and effective policies and

procedures for monitoring occupational radiation exposures included provisions to address:

(1) criteria for occupational monitoring at the licensees facility; (2) prior or concurrent

occupational radiation exposures to licensed and unlicensed radiation sources;

(3) responsibilities for individuals to properly wear dosimeters; (4) licensee-specified

dosimeter wear locations; (5) expectations for turning in dosimeters for processing at the

end of assigned wear periods; (6) lost or missing dosimeters; (7) proper storage of

dosimeters when not in use; (8) prompt evaluation of dosimeter results; (9) criteria to

evaluate or investigate unusually low or high dosimeter results; and (10) periodic reviews

and oversight of licensee dosimetry programs. Because dosimetry approaches and

programs vary widely, it is important for individuals to receive licensee-specific training on

the policies and procedures that pertain to dosimeter use.

In accordance with 10 CFR 20.1101(c), licensees shall periodically (at least annually) review

the radiation safety program content and implementation. Effective auditing and radiation

safety program reviews may allow licensees to promptly identify compliance issues

associated with occupational monitoring programs and take actions to correct any identified

deficiencies and prevent recurrence. Licensees with effective auditing programs typically

use a combination of auditing techniques, including records review and direct observation of occupationally exposed individuals. For records reviews, licensees may find it beneficial to

compare dosimeter results data with information or data related to individuals licensed

activities (i.e., radioisotopes used, quantity used, frequency of use) and unlicensed activities

(i.e., characteristics of specific x-ray-generating devices used, duration of use, frequency of

use). Some licensees have found that such comparisons can be accomplished through

automated data collection systems that can flag discrepant data or be set to flag or identify

values that meet certain thresholds established by the licensee. For direct observation, licensees may elect to perform periodic spot-checks of occupationally exposed individuals

during licensed and unlicensed activities to determine whether dosimeters are being worn

properly. If licensee evaluations determine that occupational radiation doses exceed the

limits in 10 CFR Part 20, licensees are required report to the NRC in accordance with

10 CFR 20.2203, Reports of exposures, radiation levels, and concentrations of radioactive

material exceeding the constraints or limits.

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/

/RA/

Christopher G. Miller, Director

Division of Reactor Oversight

Office of Nuclear Reactor Regulation

Kevin Williams, Director

Division of Materials Safety, Security, State, and Tribal Programs

Office of Nuclear Material Safety

and Safeguards

Technical Contact:

Janine F. Katanic, PhD, CHP, NRC Region IV

(817) 200-1151

E-mail: Janine.Katanic@nrc.gov

ML21152A239

EPIDS No. L-2021-GEN-0006 OFFICE

Author

QTE

Authors BC

OE

NRR/DRO/IOEB/PM

NRR/DRO/LA

NAME

JFKatanic/RA/

JDougherty /RA/

LRoldanOtero/RA/

JPeralta

BBenney

IBetts

DATE

6/8/21

6/3/21

6/2/21

6/16/21

6/22/21

06/21/21 OFFICE

NRR/DANU/NPUF/BC

NRR/DRO/IOEB/BC

NMSS/MSST/D

NRR/DRO/D

NAME

JBorromeo

LRegner

KWilliams

KMorgan- Butler for

CMiller

DATE

6/22/21

7/22/21

7/29/21

8/04/21