NRC ISSUES NEW GUIDANCE ON RELEASE OF THYROID PATIENTS 

ADMINISTERED RADIOACTIVE IODINE 

 The Nuclear Regulatory Commission has issued new guidance to medical licensees to 

strengthen existing precautions against the possibility that infants and young children who come 

in contact with thyroid cancer patients may receive unnecessary doses of radiation. 

 The guidance was prepared in response to concerns raised by the International 

Commission on Radiation Protection, most recently in its 2007 recommendations on radiation 

protection, and in a Petition for Rulemaking submitted by Peter G. Crane. 

 The guidance recommends that patients given therapeutic doses of radioactive iodine-131 

should avoid direct or indirect contact (for example, through shared living space) with infants 

and young children for a specific period of time following the therapy. The guidance also 

recommends that physicians should consider hospitalizing patients whose living conditions may 

result in the contamination of infants and young children. 

The new guidance is explained in a Regulatory Issue Summary (RIS) for NRC medical 

licensees and for medical licensees in the 35 Agreement States that regulate the use of 

radioactive materials. 

 “These simple precautions – including, if appropriate, hospitalization of the patient – can 

avoid unnecessary exposure for children, who can be more sensitive to radiation than adults,” 

said Charles Miller, director of the NRC’s Office of Federal and State Materials and 

Environmental Management Programs, which includes responsibility for licensing the medical 

uses of radioactive materials. 

 NRC regulations, implemented in 1997, allow licensees to release patients treated with 

radioactive material if the total radiation dose to any other person exposed to the patient is not 

likely to exceed 500 millirem. To put this in context, the average person in the United States 

receives about 300 millirem each year from natural background radiation. 

 These regulations were based on the assumption that internal doses to family members or 

others from a patient released following iodine therapy would be small compared to external 

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No. 08-097 May 16, 2008
doses received from being near the patient. However, concern has increased in recent years that 

contamination of infants and young children with saliva from a patient in the first few days 

following treatment may result in significant radiation doses to the child’s thyroid. There have 

been no known incidents of infants or young children being contaminated in this way. 

 The new guidance for licensees to provide patients or their guardians includes: 

• A recommendation that patients avoid direct or indirect contact with infants and young 

children for a specific period of time, for example by having the children stay outside the 

home with other family members; 

• A recommendation for patients to have adequate living space at home (such as a bedroom 

and bathroom) that can be used exclusively by the patient for a specific period of time; 

and 

• Information on the potential consequences, if any, of failure to follow these 

recommendations. 

The guidance also suggests that licensees consider hospitalization for patients whose 

living conditions may result in contamination of infants and young children. The specific period 

of time for patients to follow these recommendations would be determined by the physician, 

depending on the amount of iodine-131 administered; typically, this period would be for two to 

seven days following treatment. 

In his Petition for Rulemaking, Peter G. Crane requested that the NRC revise its patient 

release regulation to require hospitalization of thyroid patients administered a certain amount of 

iodine-131. The NRC has determined that additional rulemaking is not necessary because current 

NRC regulations provide adequate protection to family members and others. In addition, the 

agency believes issuing new guidance to medical licensees will effect a change in practice more 

quickly and efficiently than developing and implementing new regulations. 

 Regulatory Issue Summary 2008-11, “Precautions to Protect Children Who May Come in 

Contact with Patients Released After Therapeutic Administration of Iodine-131, and the new 

guidance will be available on the NRC Web site here: http://www.nrc.gov/reading-rm/doccollections/gen-comm/reg-issues/2008/index.html . Previous guidance for licensees to provide 

patients is available in Appendix U of NUREG-1556, volume 9, revision 2, “Program-Specific 

Guidance About Medical Use Licensees,” available at http://www.nrc.gov/reading-rm/doccollections/nuregs/staff/sr1556/v9/r2/ . 

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