UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF FEDERAL AND STATE MATERIALS 

AND ENVIRONMENTAL MANAGEMENT PROGRAMS

WASHINGTON, D.C. 20555-0001

 March 15, 2007

NRC INFORMATION NOTICE 2007-10: YTTRIUM-90 THERASPHERES AND ®

SIRSPHERES IMPURITIES ®

ADDRESSEES

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. 

PURPOSE

The NRC is issuing this Information Notice (IN) to alert addressees to the presence of

radioactive contaminants in two variations of commercially available Yttrium-90 (Y-90) labeled

microspheres, “SIRSpheres ” and “TheraSpheres ,” manufactured by Sirtex Medical, Inc. and ® ®

MDS Nordion, respectively and the possible problems with their disposal in accordance with

10 CFR 35.92. Recipients should review the information, contained in this IN, for applicability to

their facilities, and consider actions, as appropriate. However, recommendations contained in

this IN are not new NRC requirements; therefore, no specific action nor 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.

BACKGROUND

TheraSpheres and SIRSpheres are therapeutic devices that deliver radiation directly to

® ®

tumors in the liver, using glass or resin microspheres. Y-90 is either integrated into the glass

matrix or attached to the resin beads with diameters from 15 to 35 microns (μ). Millions of

these microspheres are injected into the hepatic artery, the liver's main blood vessel, in a

manner that preferentially traps them in the capillary bed feeding the tumor, and not the larger

blood vessels feeding healthy tissues. The SIRSpheres and TheraSpheres are designed to

® ®

deliver radiation directly to tumors, while sparing healthy tissues.

DESCRIPTION OF CIRCUMSTANCES

On March 20, 2006, the staff at the Vanderbilt University, Department of Radiology and

Radiological Science, informed NRC’s Operation Center of its discovery of the presence

of radioactive contaminants in SIRSpheres and TheraSpheres . As a follow-up, on March 21,

® ®

2006, Vanderbilt University staff, in a letter to the Radiological Devices Branch of the U.S. Food

and Drug Administration (FDA), explained that they detected contaminants in the samples by

using a high-purity germanium detector.

ML063470020
IN 2007-10

Page 2 of 2

The Y-90 SIRSpheres sample contained detectable amounts of Yttrium-88 (Y-88), with a half- ®

life of 106.6 days and the TheraSpheres sample had measurable amounts of the following

®

radionuclides: Y-88; Europium-154 (half-life 8.8 years); Europium-152 (half-life 13.6 years);

Cobalt-57 (half-life 270.9 days); and Cobalt-60 (half-life 5.27 years). It is important to note that

only one sample from each device was analyzed. Further characterization of radioactive levels

in more samples may yield more accurate results.

DISCUSSION

The main reason the Vanderbilt University, Department of Radiology and Radiological Science

reported this issue, to both NRC and FDA, was because the samples of TheraSpheres , held ®

for decay-in-storage, appeared to be radioactive for much longer than would have been

expected, because of the presence of Y-88 and other contaminants. 

The staff at the Vanderbilt University, Department of Radiology and Radiological Science

performed a preliminary evaluation of the radiation dose that might be delivered to the liver of

an adult, assuming 100 percent of the activity of the microspheres containing contaminants was

distributed uniformly in the liver and was removed only by physical decay. Based on this

evaluation, the dose to the liver from the contaminants did not exceed the medical event limit,

i.e., the dose delivered did not differ from the prescribed dose by 20 percent or more, and did

not differ from the prescribed dose by more than 0.5 Sv (50 rem) to an organ. However,

licensees should be concerned with disposal of microspheres. Depending on the contaminants,

licensees may need to: (1) hold the remaining microspheres longer in decay-in-storage, in

accordance with 10 FR 35.92; (2) return the microspheres to the manufacturer; or (3) transfer

to an authorized recipient according to 10 CFR 20.2006. 

CONTACTS

This IN requires no specific action nor written response. If you have any questions about the

information in this notice, please contact the technical contact below.

 /RA/

Janet R. Schlueter, Director

Division of Materials Safety 

 and State Agreements

Office of Federal and State Materials

 and Environmental Management Programs

Technical Contact: Mohammad S. Saba, FSME

Phone: 301-415-7608

E-mail: mss@nrc.gov

Enclosure: List of Recently Issued NMSS/FSME

 Generic Communications
Enclosure 

IN 2007-10

Page 1 of 3

1

Recently Issued FSME/NMSS Generic Communications

Date GC No. Subject Addressees

12/13/06 RIS-06-27 Availability of NRC 313A Series of

Forms and Guidance for their

Completion

All NRC medical-use licensees,

commercial nuclear pharmacies, and

U.S. Nuclear Regulatory Commission

(NRC) Master Materials Licensees. All

Agreement State Radiation Control

Program Directors and State Liaison

Officers.

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.

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

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.
Enclosure 

IN 2007-10

Page 2 of 3

Date GC No. Subject Addressees

2

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.

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
Enclosure 

IN 2007-10

Page 3 of 3

Date GC No. Subject Addressees

3

07/10/06 IN-06-13 Ground-W ater 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 W hen

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.

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 Reading Room/Document Collections.