Radiation safety in the treatment of patients with thyroid diseases by radioiodine 131i: practice recommendations of the american thyroid association

Volume 21, Number 4, 2011ª Mary Ann Liebert, Inc.
DOI: 10.1089/thy.2010.0403 Radiation Safety in the Treatment of Patients with Thyroid Diseases by Radioiodine 131I: Practice Recommendations of the American Thyroid Association The American Thyroid Association Taskforce on Radioiodine Safety James C. Sisson,1 John Freitas,2 Iain Ross McDougall,3 Lawrence T. Dauer,4 James R. Hurley,5 James D. Brierley,6 Charlotte H. Edinboro,7,* David Rosenthal,8,{ Michael J. Thomas,9,{ Jason A. Wexler,10,* Ernest Asamoah,11,{ Anca M. Avram,1,* Background: Radiation safety is an essential component in the treatment of patients with thyroid diseases by 131I.
The American Thyroid Association created a task force to develop recommendations that would inform medicalprofessionals about attainment of radiation safety for patients, family members, and the public. The task force wasconstituted so as to obtain advice, experience, and methods from relevant medical specialties and disciplines.
Methods: Reviews of Nuclear Regulatory Commission regulations and International Commission on Radio-logical Protection recommendations formed the basic structure of recommendations. Members of the task forcecontributed both ideas and methods that are used at their respective institutions to aid groups responsible fortreatments and that instruct patients and caregivers in the attainment of radiation safety. There are insufficientdata on long-term outcomes to create evidence-based guidelines.
Results: The information was used to compile delineations of radiation safety. Factors and situations that governimplementation of safety practices are cited and discussed. Examples of the development of tables to ascertain thenumber of hours or days (24-hour cycles) of radiation precaution appropriate for individual patients treated with 131I for hyperthyroidism and thyroid cancer have been provided. Reminders in the form of a checklist are pre-sented to assist in assessing patients while taking into account individual circumstances that would bear onradiation safety. Information is presented to supplement the treating physician's advice to patients and caregiverson precautions to be adopted within and outside the home.
Conclusion: Recommendations, complying with Nuclear Regulatory Commission regulations and consistent withguidelines promulgated by the National Council on Radiation Protection and Measurement (NCRP-155), can helpphysicians and patients maintain radiation safety after treatment with 131I of patients with thyroid diseases. Bothtreating physicians and patients must be informed if radiation safety, an integral part of therapy with 131I, is to beattained. Based on current regulations and understanding of radiation exposures, recommendations have beenmade to guide physicians and patients in safe practices after treatment with radioactive iodine.
1Division of Nuclear Medicine, Department of Radiology, University of Michigan Health System, Ann Arbor, Michigan.
2Department of Radiology, St. Joseph Mercy Hospital, Ypsilanti, Michigan.
3Departments of Radiology (Nuclear Medicine) and Medicine (Endocrinology), Stanford University Medical Center, Palo Alto, California.
4Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York.
5Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Weill Cornell Medical College, New York, New York.
6Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Canada 7Exponent, Inc. Health Group, Menlo Park, California.
8Division of Endocrinology, Nassau University Medical Center, East Meadow, New York.
9Carolina Endocrine, P.A., Raleigh, North Carolina.
10Washington Hospital Center, Washington, District of Columbia.
11Diabetes and Endocrinology Consultants, Indianapolis, Indiana.
12Department of Endocrine Surgery, Cleveland Clinic, Cleveland, Ohio.
13Western Slope Endocrinology, Grand Junction, Colorado.
*ATA Public Health Committee Liaison.
{ATA Clinical Affairs Committee Liaison.
roles of the treating physician and the radiation safety officer(RSO) in individualizing the precautions for each patient This document presents recommendations to provide while allowing the referring physician to assist in preparing health providers with reasoned instructions on radiation appropriate and adequate pre- and post-therapy actions. The safety for patients, their families, caregivers, and the public after hierarchy of authority and responsibility for radiation safety radioiodine (131I) therapy. The recommendations should help is delineated in Table 1. Untoward short- and long-term ef- to ensure compliance with federal regulations of the Nuclear fects of radiation on the treated patient, such as sialadenitis, Regulatory Commission (NRC) and reduce the potential for lacrimal duct obstruction, red marrow suppression, radiation harmful radiation exposure to others, and also to recognize that pneumonitis, and secondary neoplasms, are not addressed.
required actions may differ when attaining compliance with However, breast radiation is discussed as an extension of re- existing local regulations of other jurisdictions, for example, in Canada. Although harm from radiation exposure to personalcontacts of 131I-treated patients has not been shown, these recommendations follow the principle of reducing radiationexposure to levels that are as low as reasonably achievable In 2008, the American Thyroid Association (ATA) assem- (ALARA). Inherent within ALARA is an acknowledgement bled a multidisciplinary task force to formulate recommen- that even unapparent radiation injuries are cumulative, and dations for 131I safety precautions. The ATA Board of that, over time, small effects contribute to definitive risks.
Directors desired that these recommendations reflect all spe- These recommendations are derived from a review of cialties involved with radioiodine treatments and safety for current practices, expert opinions, and the literature. They thyroid patients, their families, caregivers (a term that includes are not meant to be evidence-based guidelines since there are roommates and friends), and the public. They appointed rep- insufficient data on long-term outcomes on which to base resentatives from the relevant disciplines, including Nuclear use or lack of use of any radiation exposure precautions.
Medicine, Radiation Safety, Medical Physics, Endocrinology, The recommendations are based on data derived from rele- and Endocrine Surgery. Liaisons from the Clinical Affairs and vant measurements of radiation exposure, 131I clearance and Public Health committees also assisted the process. Funding excretion, and reports of the impact of precautions in limiting was derived solely from the general funds of the ATA. The final radiation exposure. They are meant to clarify safety precau- document has been approved by the ATA Board of Directors tions necessary and helpful in complying with NRC regula- and officially endorsed by the: Academy of Molecular Imaging tions and reducing doses to ALARA. They emphasize the (AMI), American Association of Endocrine Surgeons (AAES), Table 1. Hierarchy of Authority and Responsibility for Radiation Safety in Treatment  Established by U.S. Congress Authority Establishes policies and regulations.
Grants licenses to institutions and physicians to treat patients with radioiodine-131.
Ensures radiation safety for patients, families, caregivers, and the public.
Issues instructions regarding new policies and regulations.
Receives reports of medical events, that is, breaches in radiation safety.
 The Advisory Committee on the Medical Uses of Isotopes (ACMUI) advises NRC on policy and technical issues that arise in the regulation of the medical uses of radioactive material in diagnosis and therapy. www.nrc.gov/about-nrc/regulatory/advisory/acmui.html In ''Agreement States,'' agencies are established by state governments to monitor radiation safety and report to NRC. In otherstates, the NRC directly oversees observances of radiation safety.
Radioiodine Treatment Teams (for licensure and reports: www.nrc.gov/10CFR 35.190) Develops and oversees treatment protocols for patients with usual radiation safety risks.
Provides specific advice for patients with unusual safety risks.
Reports medical events to State Agency or to NRC.
 A Radiation Health Physicist may bridge the responsibilities between RSOs and Treatment Prescription and  Duties of Treatment Prescription and Implementation Group (consists of physicians and clinical support staff ) With RSO, create treatment protocols for patients with usual radiation safety risks.
With RSO, plan specific treatments for patients who may require additional safety precautions.
Deliver oral and written advice specific to each patient.
Obtain written consent for therapy by patient or guardian.
Respond to medical events observed or reported.
Report to, discuss with, RSO all medical events in radiation safety.
aNRC also regulates radiation safety through specific guidance programs for other organizations such as industrial radiography, commercial radiopharmaceuticals, and nuclear reactors.
RADIATION SAFETY AFTER TREATMENT WITH RADIOIODINE American Academy of Otolaryngology-Head and Neck Surgery patient instructions (4). Further, even within some institu- (AAO-HNS), American College of Nuclear Medicine (ACNM), tions, there was disparity in radiation safety instructions American Head and Neck Society (AHNS), Endocrine Society provided by the referring physician, the Nuclear Medicine (ENDO), European Society of Endocrinology (ESE), Interna- Department, and/or RSO. As part of this survey, actual pa- tional Radiation Protection Agency (IRPA), Latin American tient instruction handouts were solicited from respondents; Thyroid Society (LATS), and Ukrainian Association of Endo- these were reviewed, evaluated in detail, and found to range crine Surgeons (UAES). The American College of Surgeons from quite proscriptive to relatively lax. Additionally, there (ACS) and the American Congress of Obstetricians and Gy- were examples of direct contradiction between sets of in- necologists (ACOG) acknowledge support of the document.
structions: for example, one advised ''use disposable utensils'' The overall goal of these recommendations was to limit and another ''to not use disposable utensils.'' Thus, there was a radiation exposure from patients treated with 131I to family need to clarify which safety precaution instructions best attain members, caregivers, and the general public, consistent with ALARA, comply with the NRC regulations, and achieve pa- ALARA and NRC regulations. The task force recognized that tient instruction uniformity so that adherence could be max- several of the precautions traditionally thought to be neces- imized and stress and confusion minimized. The results of the sary offered little benefit or protection from radiation expo- Survey were reviewed in an accompanying editorial (5).
sure, whereas others that were often overlooked served toreduce exposure. They also recognized the critical need of individualization in providing instructions so as to ensurereductions to ALARA for those involved. Individuals differ not only in their social situations but also in the activities of Recommendations by the International Commission on 131I received and rates of clearance from the body. The task Radiological Protection (ICRP)* sanction licensed facilities to force acknowledged that the RSO at each treating facility is release a patient treated with 131I from their control as long as critical in treatment planning and execution and should be the the radiation exposure to any other individual (generally, a final arbiter of precautions for any given patient. However, family member) encountering the patient will likely not exceed clinical evaluation and preparation of the patient for the 131I 5 mSv (500 mrem) per annum, and the radiation dose to a child, treatment often precedes the encounter with the RSO. A dis- a pregnant woman, or an individual not involved in the care of cussion of patient-specific radiation safety precautions should the patient will not exceed 1 mSv (100 mrem) per annum (25).
also be part of the shared decision-making with the patient According to NRC regulation 10 CFR 35.75, if any individual and the referring and/or treating physicians and should allow is likely to receive more than 1 mSv (100 mrem), then the re- the patient to select the best timing for 131I treatment and to leased patient must be provided with verbal and written in- make appropriate preparations at home and at work.
structions that will maintain doses to other individuals as low as In the United States, the NRC replaced the Atomic Energy reasonably achievable. Patients may not be released if, despite Commission in regulating unsealed sources of radioactivity precautionary measures, exposure will exceed 5 mSv (500 mrem) (Energy Reorganization Act 1974). In 1997 and in 2009 up- (15). NRC Regulatory Guide 8.39 (6) and updated guidance in dates (1), the NRC changed its pre-1997 release requirements NUREG 1556 v.9 (7) provide licensed facilities with informa- for patients treated with 131I from an ''activity-based limit,'' tion on how to implement the ''Patient Release Criteria Rule.' the amount administered expressed in millicuries (mCi) or The current NRC Patient Release Criteria allow most pa- megabecquerels (MBq) to a ''dose-based limit,'' the absorbed tients to be treated with 131I as outpatients (1). The regulations dose expressed in roentgen equivalent man (rem) or sieverts apply to all patients who are treated with unsealed radioac- (Sv). The resultant ''Patient Release Criteria Rule'' allows re- tivity, including 131I for thyroid cancer, hyperthyroidism, and lease of treated patients from control of the treating facility goiter. When outpatients who were treated for thyroid can- with higher levels of radioactivity than previously permissi- cer and hyperthyroidism and their families were instructed ble. This removed the restrictions that mandated a hospital in radiation safety, measurements demonstrated that radia- stay in isolation for patients treated with !33 mCi (1221 MBq) tion exposures within the homes did not exceed regulations of 131I. Others deemed this change in release criteria unwar- in comparable studies performed in the United States (8), ranted, and submitted a petition (2) to the NRC requesting that the ''Patient Release Criteria Rule'' be reversed. The NRCinvited public comment regarding this petition, and the ATA submitted a response supporting the established ReleaseCriteria Rule. The Rule was upheld and remains in effect.
Most of the radiation exposure from patients treated with The current regulations are less restrictive than those imposed 131I arises from high-energy gamma rays (photons). Three upon 131I therapy practices in some other nations; despite this, variables determine the amount of radiation a person receives there is no evidence that safety has been compromised, even as from a treated patient: the retained radioactivity in the pa- the care of the patient was made more efficient and economical.
tient, the distance from the patient (radiation levels decrease On the other hand, patients and the public remain concerned with square of the distance from the source), and the duration about radiation exposure from the current practices (3).
of exposure (see Occupancy Factor (OF) under Definitions Significant variability in the instructions for 131I therapy precautions provided to patients by ATA members andhealth-care providers, in general, became apparent when the *ICRP (www.icrp.org) is an independent, international organi- zation comprised of leading scientists and policy makers in the ATA began to gather this information. A subsequent survey field of radiological protection. ICRP provides recommendations of ATA members about their institutions' 131I safety precau- and guidance on all aspects of protection against ionizing radia- tions confirmed the existence of substantial differences in tion, but has no regulatory authority in the United States.
below). The retained radiation activity in the patient is a The required information may be found in a TEDE table, a function of several factors, including, but not limited to, (i) the supplement, that provides mrem (mSv) as a function of ad- administered activity, (ii) the mass and function of thyroid ministered activity and contact hours at 1 m. In examples with tissue as reflected in the concentrations of serum free T4 and assumed values for the variables, calculations demonstrated thyrotropin (TSH), (iii) the radiopharmaceutical, and (iv) the that patients could be released without exceeding applicable patient's hydration status and renal function. Therefore, the dose limits after treatment with 57 mCi (3177 MBq) for hyper- cumulative external exposure from a patient who has received thyroidism and 150 mCi (5550 MBq) for thyroid cancer (7).
a given activity of 131I will vary substantially among thyroidcancer patients who are hypothyroid or euthyroid at the time of treatment (11) and among hyperthyroid patients (12).
tablished for a distance of 1 m from a radiation source. To Compared to those with hyperthyroidism, thyroid cancer facilitate understanding by the patient and family members, patients usually receive larger initial 131I activities, but, lacking 1 m is approximated to ' >3 feet,'' and to help ensure safety, a thyroid gland, retention declines more rapidly through uri- family members and caregivers of a treated patient are ad- nary excretion, and especially when euthyroid patients are vised to remain well beyond 6 feet as much as possible. The prepared for treatment with recombinant human TSH rather days (24 hours cycles) when a patient may expose others to than by hormone withdrawal (11). Hyperthyroid patients re- doses exceeding the foregoing limits noted above is the ''re- tain a greater percentage of radioactivity (more is sequestered in the thyroid gland) and also manifest higher levels of circu-lating radioiodinated thyroid hormones. The effective half-life of 131I in a hyperthyroid gland is usually about 5 days (12).
home, the OF is usually 0.25, which means that an individual Another potential radiation exposure pathway is ingestion will be exposed to a patient treated with 131I at 1 m 25% of the of 131I excreted/secreted by the treated patient. The majority time, here termed ''daytime restriction.'' The assumed OF for a of the excretion of radioiodine occurs via the urine; small person sleeping with a patient is 0.33, and, because sleeping is amounts are present in stool, saliva, and other body fluids.
assumed to be at a distance of 0.3 m, exposure is thereby in- Contact with areas contaminated with excreted or secreted creased and the days (24 hour cycles) containing ''nighttime 131I from a treated patient could be a source of ingested 131I.
restriction'' will generally exceed the limits of daytime re- This is a special concern for young children, whose thyroid glands (13) and other tissues such as breast (14) are more Annotated references, including additional citations, can be sensitive to radiation. Therefore, ICRP recommends fol- found in the Supplementary Data (available online at lowing stricter precautions to further reduce radiation ex- posure to fetuses, children, and the general public (25).
All 131I treatments must be prescribed by a provider li- censed as an authorized user and thus trained in adminis- report (6), patients may be released when 131I retained activity tration of radiopharmaceuticals. Radiation safety precautions for radionuclide therapy protocols will be created and over- Equivalents of administered activity are as follows: seen by the RSO. Additional or individualized patient-specific 1 mCi ¼ 37 MBq and 1 MBq ¼ 0.027 mCi.
precautions will also be developed by the RSO as needed(Table 1). A Radiation Health Physicist may be included in the Radioiodine Treatment Team as liaison between the RSO and lease patients, regardless of administered activity, using dose the Treatment Prescription and Implementation Group.
rate measurements and TEDE (total dose effective equivalent Individualization is stressed in predicting, calculating, and in mrem or mSv) to meet NRC criteria for release. TEDE tables measuring the retained activity in each patient.
should be developed (usually with the aid of an RSO) when It is essential that radiation safety recommendations be exposure rates are likely to be high and especially for the first discussed with each patient as soon as treatment with 131I is 8 hours after the patient is released and during which time considered. A checklist (Table 3) provides a tool to systemati- safe distances from the patient may be difficult to sustain.
cally evaluate the patient, identify potential exposure risks, Patients may be released when the 131I measured dose rate is and determine the suitable treatment setting. The required 7 mrem per hour (h) at 1 m as measured by a dose rate meter precautions will often influence the choice and timing of 131I (6). As noted above, patients also may be released when the therapy. Preparing the patient, caregivers, and employers en- TEDE of 131I is unlikely to exceed 500 mrem (5 mSv). If 100 sures familiarity with the recommendations and reduces con- mrem (1 mSv) may be exceeded in any person, pertinent cerns associated with radiation treatments. Table 4 includes a written and verbal precaution instructions are required (1,15).
spectrum of advice to patients. By editing through cross-outsand additions, advice can be made specific for a patient; it must be given verbally as well as in writing so as to enable the tion takes into account the administered 131I activity, its phys- patient to ask questions and clarify any misunderstandings.
ical half-life and exposure rate constant, OFs (see below), effective half-lives, and thyroid uptake fractions. The resultantdose equation yields 0.17 mrem hÀ1 mCiÀ1 at 1 m (16,17), where 33 mCi gives a dose rate of 5.6 mrem/h at 1 m from a patient.
that pregnancy is a contraindication to 131I therapy, and they RADIATION SAFETY AFTER TREATMENT WITH RADIOIODINE Table 2. Examples of Precaution Requirements AND RECOMMENDATIONS After Treatments with 2A-1. Hyperthyroidism [Assumes 50% uptake by thyroid, with effective T1/2 of about 5 days (12)] Sleep in a separate (6-feet separation) bed from adults for days shown.
Sleep in a separate bed from pregnant partners, infant, or child for days shown.
You may return to work after days shown.
Maximize your distance (6 feet) from children and pregnant women Avoid extended time in public places for days shown.
2A-2. Thyroid carcinoma/remnant ablation [Assumes that disappearance of 131I is biexponential with early effective T1/2 of about 0.76 days,and 2% uptake in remnant with effective T1/2 of about 7.3 days (7). Consider formal dosimetry (18) for larger administered doses given topatients with functioning carcinoma. 131I kinetics in euthyroid patients stimulated by recombinant human thyrotropin may differ fromthose used here (11)] Sleep in a separate (6-feet separation) bed from adults for days shown.
Sleep in a separate bed from pregnant partners, infant, or child for days shown.
You may return to work after days shown.
Maximize your distance (6 feet) from children and pregnant women for days shown.
Avoid extended time in public places for days shown.
2B. Duration of Safe Travel by Public Transportation (Bus, Air, etc.) [Assumes 100 mrem limit and 0.3 m distance. Other assumptions areas in Table 2A-1 and 2A-2] Travel time (hours) without exceeding regulatory dose limit Day (24-h cycles) 0 (beginning with treatment) Travel time (hours) without exceeding regulatory dose limit Day (24-h cycles) 0 (beginning with treatment) Examples should be modified to meet local and specific patient needs. These examples are based on dose rate of 0.17 mrem hÀ1 mCiÀ1 at 1 m (16,17), 500 mrem per year for family member and caregiver, 100 mrem for pregnant women, children, and the public, and OccupancyFactors for adults of 0.25 except for sleeping 0.33. Resumption of sleeping with a partner assumes a distance of 0.3 m (7).
Table 3. Eligibility Assessment Checklist It is incumbent upon the Radioiodine Treatment Team and the patient to agree upon a plan that, by environmental andpopulation assessments and by calculations, will not put others at risk of radiation exposure as identified in NRC regulationsand ICRP recommendations.
Absolute contraindications to 131I therapy (pregnancy and breastfeeding)1. Determine absence of pregnancy by: ___Pregnancy test within 72 hours prior to treatment, or___Historical evidence of hysterectomy, or___No menses for !2 years and >48 years old, or___Other incontrovertible evidence for absence of pregnancy.
2. Determine absence of lactation and/or breastfeeding: ___By interview and/or clinical examination, or___If uncertain and treatment is needed urgently, recommend 123I scan to assess breast concentration of radioiodine.
REMEMBER, Breastfeeding or pumping must not be resumed after 131I therapy.
Consider inpatient 131I therapy and consult RSO when1. Proposed 131I dose is ___!200 mCi (7400 MBq) or___TEDE, despite written instructions, is likely to exceed, 0.5 rem (5 mSv) to an adult family member or caregiver, or to exceed 0.1 rem (1 mSv) to a pregnant woman, child or a member of the general public.
2. The patient is unable to comply with oral and written instructions and therefore will require special planning because of: ___Incontinence issues;___Requires help with devices such as Foley catheters, peritoneal dialysis equipment, feeding tubes, etc.;___Cognitive/psychiatric limitations;___Travel/housing limitations;___Other limitations (name).
Information gathering for radiation safety precaution planningTravel: To home on the day of treatment or subsequently: ___Patient will drive alone and is competent to do so.
___Patient plans to use private car with a driver, or taxi, or car service. The patient must sit alone in a back seat >3 feet from the driver. If travel requires taxi or duration is over 2 hours, consult RSO.
___Patient is limited to travel by bus, train, subway, ferry, or other public conveyance. This option requires a calculation of TEDE for other individuals and approval by the RSO (see Tables 2B-1 and 2B-2).
Home: Living arrangements (relationship, age and gender of each household member) For all household members, patient must be able to stay >6 feet away most of time (care givers may approach 3 feet up to25% of the time.)Special Household Situations. Check all that apply; provide appropriate information and make an alternate arrangement:___Household member is pregnant, and the patient cannot stay at least 6 feet away all of the time.
___Household member(s) are under the age of 16, and the patient can't stay at least 6 feet away all of the time.
___Patient is responsible for the care of an infant or young child.
___There is not sufficient space to maintain >6 feet distance from others.
___Patient unable to sleep alone during nighttime restricted period.
___Patient must share a bathroom with others. (Special home arrangements: Emphasize instructions in Table 4, Step 4, Work/School: Employment or school status, including required activities, environment, contacts with co-workers or fellow students, and arrangements to commute to work/school. From all co-workers or classmates patient must be able tomaintain at least 6 feet distance at all times except for momentary encounters.
Special Work/School Situations:___Associated with children <16 years of age. If patient cannot stay >6 feet away, delay return to work___Associated with pregnant women. If patient cannot stay >6 feet away, delay return to work.
___Food preparation for others. Get special instructions from RSO/Radioiodine Treatment Team.
Commuting to work or school___Car pooling or public transportation for periods of daytime restriction: make alternate arrangement or obtain special should take measures to prevent pregnancy once treatment healthy infant development, and to ensure that additional with 131I is planned. Pregnant women should never be treated radiation treatment is not imminent.
with 131I, and a pregnancy test must be performed before the There are exceptions to the requirement for a pregnancy time (usually within 72 hours) of treatment in all women, test, but there must be incontrovertible evidence that preg- from menarche to 2 years after menopause, who could be- nancy is impossible, for example, surgical hysterectomy.
come pregnant. Pregnancy should be delayed for at least6 months after radioiodine therapy, a delay based on the need There is a delay between conception and the to normalize thyroid levels for a successful pregnancy and sensitivity of tests to detect pregnancy. Blood and urine RADIATION SAFETY AFTER TREATMENT WITH RADIOIODINE Table 4. Safety Instructions for Patients Receiving Radioiodine Treatment To be given verbally and in writing and edited as appropriate for the patient.
With regard to your radioiodine therapy, please consider the following.
Step 1: Talk with your doctor or a member of the Radioiodine Treatment Team aboutWhy treated women must When treated men can consider fathering a child.
Who will give you the radioiodine therapy, and where and when this will happen.
Step 2: Make preparations before treatment and talk with your doctor or a member of the Radioiodine Treatment Team aboutthe following specific items;Obtaining Wipes and/or toilet paper that can be flushed down the toilet; Disposable gloves if others will be helping to take care of you; Heavy duty (doubled if possible), leak proof, specified plastic trash bags for tissues, paper towels and other things thatmay be contaminated and trashed; If you are well enough, it is best to drive yourself; If you ride with someone else, confirm she is not pregnant, and maintain a distance of >3 feet (use the back seat onopposite side of the driver); When and where you can take necessary trips; When it is safe to use public transportation; Inability to control your urine or bowels; Using special medical equipment, such as catheters, ostomy bags, or anything that could be contaminated by yourbody fluids; Getting sick easily (throw up or get woozy); Not being able to go directly home; arrangements must be made through your treatment team; hotel and motel staysare not recommended.
Step 3. Your doctor or member of the Radioiodine Treatment Team will discuss with you the following items and fill in thenumber of days related to each.
________ Days that you need to stay >3 feet away from your adult family members and caregivers for at least 18 hours a day, and at least 6 feet away as much as possible.
________ Days that you need to stay >6 feet away from babies, children younger than 16 years old and pregnant women.
________ Days that you need to stay away from work and close contact with others in public places (movies, shopping, ________ Days that you need to stay away from school or day-care (includes both teachers and students).
Step 4. Recommendations for after therapyAt home Specific recommendations. Ask your doctor for the number of days to: Sleep alone in a bed that is >6 feet away from another person, and, if possible, use a separate bedroom or sleepingroom all by yourself; Move your bowels every day and use a laxative if you need help; Empty your bladder (urinate) every hour or so during the day of, and day after your radioiodine treatment; followyour doctor's advice on how much to drink; Use wipes (preferably flushable) to clean the toilet seat after use; men should sit down to urinate and use wipes toremove splatter of urine; wipe yourself dry after urinating so that you do not drip; For a phone you share with others, after use, wipe off the mouthpiece, or, while using, cover the phone with a plasticbag that, after use, is placed in specified plastic trash bag.
General Recommendations especially for patients sharing a bathroom Flush the toilet after each time you use it; flush toilet paper and wipes; Always wash your hands well after using the toilet; Rinse the sink and wash your hands after brushing your teeth to wash away the saliva (spit); Do not share your toothbrush, razor, face cloth, towel, food or drinks, spoons, forks, glasses and dishes; Shower every day for at least the first 2 days after your treatment; Do not cook for other people. If cooking is necessary, use plastic gloves and dispose of in the specified plastic trash bag; Wash your dishes in a dishwasher or by hand; it is better not to use disposable (throw away) dishes which must be putinto a specified plastic trash bag; Try to flush any tissues or any other items that contain anything from your body, such as blood, down the toilet; itemsthat cannot be flushed, such as menstrual pads, bandages, paper/plastic dishes, spoons and forks and paper towelsshould be put in the specified plastic trash bag; Wash your underwear, pajamas, sheets and any clothes that contain sweat, blood or urine by themselves; use astandard washing machine; you do not need to use bleach and do not need extra rinses; Have any one who helps you clean up vomit, blood, urine, or stool wear plastic gloves; the gloves should then be putin the specified trash plastic bag.
Keep the specified plastic trash bags separate from other trash; keep the bags away from children and animals; A member of your Radioiodine Treatment Team will tell you how and when to get rid of the specified plastic trashbag; you may be asked to bring the bag back to your treatment facility, or, after 80 days, the bag may be removed asother trash bags.
Usually pets will not receive enough radiation to harm them. But do not sleep with pets (ask your doctor for how long)since your saliva, perspiration or other secretions may be carried away by the pet.
Outside the Home. Ask Your Doctor or a member of the Radioiodine Treatment Team when: It will be safe to eat out, go shopping and attend events such as religious services, parties and movies; You will be able to return to work and to care for or teach others; Special or longer distance travel is possible (Note: For up to 3 months or more following radioiodine treatment youmay set off radiation detectors at: national borders, airports, bus and train stations, tunnels, bridges, trash collectionsites and even your place of employment); a member of your Radioiodine Treatment Team will issue you a letter orcard describing the therapy and the phone number of a person knowledgeable about your treatment (usually at thetreating facility) in case local law enforcement agents need to check on this information; you should keep the letter orcard containing the information with you whenever you are traveling for at least 3 months.
You will get an information card or letter at the time of your treatment that will show the date, type and amount ofradioiodine that you were treated with; carry this card with you at all times for at least 3 months following yourtreatment; If you are in a traffic accident or any other medical emergency during the first week after your treatment, you shouldshow this card to the medical people to let them know about the date and dose of your radioiodine treatment.
IMPORTANT INFORMATION FOR PATIENTS ON RISKS OF RADIATIONRadiation exposure to others should always be As Low As Reasonably Achievable, a goal often abbreviated as ALARA. Ifyou follow the above advice, the radiation from you to others is likely to be less than what they receive from radiation innature over a year's time.
Please phone us if:  you have any questions, and particularly if any of the above instructions cannot be followed and/or if you see anything that may have accidentally or unavoidably increased exposure of others to radiation.
We welcome your input on how we can improve our methods and advice to patients.
Phone: _______________________________________Sincerely yours, ______________________________________________ pregnancy tests are usually positive at about 1 week of ges- obstetrician, and, in an expedited fashion, the patient must tation or as stated in the package insert. Current urine and be counseled on possible pregnancy outcomes and treat- serum tests are of nearly equal sensitivity. There may be some treated patients who later discover that they were In a meta-analysis, no evidence was found that 131I pregnant at or near the time of the 131I dosing. In these treatments impaired fertility (21). In another meta-analysis, situations, the pregnancy will be in a very early stage, and radioiodine therapy for thyroid cancer in young men has before the ability of the fetal thyroid gland to concentrate been associated with transient testicular dysfunction ex- iodide, which commences about 10 to 12 weeks of gestation pressed as elevated serum FSH levels for up to 18 months (19,20). However, there is still a concern for fetal whole- after treatments, and some articles reported low sperm body radiation exposure. Such cases should be handled on a counts exceeding 1-year duration (22). Limited data indi- case-by-case basis, and a qualified medical physicist should cate that fathering a child within 3 months of radiation estimate the absorbed radiation dose to the fetus. In a lit- exposure is not associated with an increase in congenital erature review of patients treated with 131I during preg- anomalies or fetal loss, and there is no evidence of long- nancy, each of 13 patients who received as little as 15 mCi term reduced fertility. However, men should be advised after the 10th week of gestation gave birth to babies with that full fertility may not occur until after 1 year, and at- hypothyroidism or cretinism; 4 patients who were treated tempts to produce pregnancy should best await a time before the 10th week delivered normal infants (20). If a when they are fully recovered from 131I therapy, a period of pregnant woman is treated, data must be provided to her RADIATION SAFETY AFTER TREATMENT WITH RADIOIODINE vate car. For this situation, there is no time or distance limitexcept that the patient should drink sufficient fluids to ensure frequent urination and thereby reduce radioiodine in the cently stopped breastfeeding should not be treated with 131I bladder. Advance planning should include safety in the use of since the lactating breast concentrates a substantial amount of iodide. Breastfeeding must be stopped at least 6 weeks before If the patient must ride or drive with another person, then administration of 131I therapy, and a delay of 3 months will time and distance constraints apply. If the person in the ve- more reliably ensure that lactation-associated increase in hicle is also a member of the patient's household, the allow- breast sodium iodide symporter activity (23) has returned to able exposure during the car trip may limit subsequent normal. If the 131I treatment is urgent or there is concern re- exposure within the home. TEDE tables should be constructed garding residual breast uptake, an 123I scan will detect whether to determine how radiation safety limits the duration of the breast concentrations of radioactivity greater than normal trip with another occupant; the minimum separation distance (substantially above background) should impose a delay in should be >3 feet, for example, one sitting in the driver's seat therapy. Involution of lactating breasts is variable as demon- and the other in the passenger-side back seat. Use of a larger strated in 123I scans; in a small series, there was evidence that vehicle, such as a van, would permit further separation and bromocriptine accelerates involution (24); however, this agent consequently a longer period of safe travel. Again, frequent must be prescribed in the ''off label'' mode. Breastfeeding emptying of the patient's bladder should be emphasized but should not be resumed after administration of 131I. Breast- with afore thought to safety in the use of restrooms.
feeding can be safely undertaken after future pregnancies.
Public transportation or mass transit should be avoided throughout restricted periods as recorded in Table 2B-1 and 2B-2. Special circumstances are in the purview of the RSO and two reasons. The first and most critical is to prevent 131I in the will be based on treatment characteristics and also patient milk from reaching the infant and particularly the infant's reliability. In a different analysis, International Commission thyroid gland. The second reason is to limit radiation of the on Radiological Protection has published recommendations breast tissue, which, via the increased expression of sodium (25) that allow use of public transportation by some patients iodide symporter during lactation, promotes 131I concentra- treated for hyperthyroidism: the patient may use this trans- tion. If a woman is intermittently breastfeeding or if there is portation for 0.5 hour after 22 mCi (800 MBq) with progres- obvious milk still present despite cessation of nursing, then131 sion to 3.5 hours after 5.4 mCi (200 MBq).
Radiation detectors at ports of entry.
Atomic Energy Agency notes that when releasing patients containing radionuclides with measurable gamma ray emis- dicted body retentions of 131I determine when the dose at 1 m sions, unanticipated detection of radiation from such people is will be less than the regulatory limit for patient release. Dur- possible, or even likely, by radiation-detection systems at ing the period in which exposure at 1 m will exceed this limit places of employment, international borders, airports, train (i.e., daytime restriction), adult family members and care- stations, bridges, tunnels, and other areas. With current givers should remain >6 feet away except during the 25% OF technology, it is possible to detect 131I activity as little as time at 1 m. Invoking the ALARA principle, all individuals 0.01 MBq of 131I at 2 to 3 m (26). It is possible that patients should stay at least 6 feet away from each treated patient as treated with 131I could trigger alarms at such detection sites much as possible throughout the restricted period. Adult for 95 days or longer after treatment (26,27). Although the family members or caregivers may be closer than 1 m for brief amount of 131I does not endanger the public, if detected, it periods, preferably for only minutes. The duration of these likely will lead to time-consuming explanations and docu- distance restrictions depends largely on the amount of thyroid tissue and the rate of clearance of retained activity that will If, within 4 months of receiving 131I therapy, travel is be assessed by a licensed practitioner in consultation with planned, particularly across international borders or via air- ports, tunnels, and/or over bridges and wherever inspection Table 2A-1 and 2A-2 give examples of days (24-hour cycles) is likely, a form should be provided to the patient. The form required for compliance with 1-m distance restrictions. These should specify the date of treatment, the radionuclide and data are based on NRC guidelines, published rates of radia- activity administered, the treating facility, and the name and tion exposure at 1 m, and published rates of 131I clearance in telephone number of a contact individual knowledgeable hyperthyroid and in hypothyroid cancer patients. Similar ta- bles may be constructed for patients who will receive differentactivities of 131I and/or who are euthyroid on replacement or suppressive therapy with thyroid hormone (and are stimu-lated by recombinant human TSH).
Constraints on time and distance apply to travel, home, is not recommended after treatment with 131I. Without spe- work, school, and social activities.
cific environment assessments and dose-rate calculations,hotels and motels should be avoided for the periods of day-time restrictions in Table 2A-1 and 2A-2. The RSO should be consulted if a patient must travel a substantial distance after treatment, requires additional follow-up imaging, or cannot or other impairment, the patient should drive alone in a pri- travel home without an overnight stay.
(see below and Table 4). Flushable clean-up items should be hours of sleep is 0.33 and the anticipated distance between flushed down the toilet. Nonflushable items such as paper sleeping partners is 0.3 m. Patients should sleep alone and at towels should be disposed of in the specified trash bag. If a least 6 feet away from any other individual throughout caregiver assists with the clean-up, disposable plastic gloves the nighttime restricted period. Use of a separate bedroom or should be worn during the clean-up process and then dis- sleeping area would be best. Table 2A-1 and 2A-2 give posed of in the specified trash bag.
examples of restriction periods and demonstrate the more ex-tended nighttime restricted periods for sleeping with another.
During the all restricted periods, patients should If there are pregnant women, infants, and children under 16 follow these recommendations. Emptying of the bowel mod- years of age in the home, arrangements should ensure that a erately reduces radiation to the patient and also to individuals distance >6 feet can be maintained between the patient and nearby. To ensure a daily bowel movement, a laxative may be these occupants for the entire restricted time. Input from the used. Wiping and flushing should follow the same directions as RSO should be sought early in the planning process to adapt for urination. Also, defecation accidents require the same pre- post release radiation precautions to the patient's home con- cautions for clean-up as described under urinary incontinence.
figuration. Having a treated parent staying in the home withchildren is often problematic due to children's needs and de- Since 131I concentrations are present in the saliva sires to be near the treated parent. Special arrangements should for as long as 7 days, patients should avoid kissing, especially be made for children to stay with relatives or friends; alterna- of children, for the period in which sleeping with others is tively, the treated parent may stay with relatives or friends restricted. Radioactive saliva can contaminate food utensils, where children and pregnant women are absent.
beverages, toothbrushes, sinks, pillowcases, and telephonemouthpieces, so precautions apply to all of these items.
However, disposable food utensils require special waste con- school, constraints in time and distance are similar to those in siderations; washable utensils are preferable. After eating, the home environment, with special emphasis on preventing washing food utensils, glassware, and dishes in a dishwasher exposure to pregnant women and children.
or by hand will suffice; the dishes may be washed with those ofthe family. If telephone mouthpieces are shared, they shouldbe wiped carefully after use by the patient or covered with an easily removed plastic bag. Personal cell phones are preferred.
Hygiene precautions are meant to reduce not only external exposure but also ingestion of 131I from secretions and ex- ommendations apply to the daytime periods of restrictions.
Blood from wounds, epistaxis, menstruation, and other Urine is the primary excretion route for 131I and is sources typically contains low levels of radioactivity, but, maximal during the first 48 hours after treatment. Sufficient nevertheless, requires precautionary clean up; again, anyone fluid (3-4 L/day) should be consumed to enable frequent providing assistance should use plastic gloves. Bandages, urination but care should be taken for hypothyroid patients, clean-up materials, menstrual pads, and gloves should be and particularly those who are elderly, because there is re- disposed of in the specified trash bag. Nasal mucus can also duced free-water clearance that may lead to hyponatremia.
contain 131I and tissues, unless flushable, should be disposed Diuretics should be discontinued if possible. Patients should adjust their fluid intake to enable voiding every hour whileawake for the first day after treatment and continue to void A small amount of 131I will appear in sweat, often for the next few days to reduce radiation exposure to the but this could be transferred by hands to the mouths of family urinary bladder and adjacent internal organs.
members. Bedding and bed clothes should be handled with The following recommendations are for all restricted peri- care during the periods that restrict sleeping with another.
ods. Both men and women should sit for urination to avoid Patients should wear disposable plastic gloves if they must splatter of radioactive urine. Patients should wipe themselves prepare meals for others during the same restricted periods.
dry to avoid dripping and contamination of clothing. Flush- Wiping exercise equipment and similar instruments used by ing the toilet twice after each use is often recommended, but, others during the first 48 hours after treatment with flushable unless small children or animals gain access to the toilet, there wipes should be sufficient to remove any hazard; the paper is little additional benefit from this. However, wiping the rim towels and nonflushable clean-up materials should be dis- of the toilet with damp toilet paper (or a flushable wipe) that is posed of in the specified trash bag. Work and/or exercise subsequently flushed may remove a source of radiation that clothing that are heavily soiled with perspiration should be can reach others. This is especially important when a bath- washed immediately or kept away from household members room is being shared with household members or a public until laundered. Likewise, bed clothes soiled with perspira- restroom is used. Handwashing after using the toilet should tion and/or other secretions and should be laundered before If urinary incontinence is anticipated, then discussion with the RSO during the planning stages is important, and the Nausea occurs frequently and vomiting occa- duration of the recommendations should be determined on an sionally, especially in children, after administered activities of individual basis. Incontinence pads must be disposed of in a 300 mCi (11,100 MBq) or more (28). The gastric mucosa se- heavy duty (preferably double) plastic trash bag (hereafter cretes iodide by the same mechanism as chloride so that referred to as specified trash bag) devoted to radiation waste vomitus contains substantial amounts of 131I for days after the RADIATION SAFETY AFTER TREATMENT WITH RADIOIODINE administered activity has been absorbed. Prophylactic anti- 4. Greenlee C, Burmeister LA, Butler RS, Edinboro CH, Mor- emetics may lessen the gastrointestinal symptoms. For all rison SM, Milas M 2011 Current safety practices relating to I- periods of restriction, vomitus should be collected using 131 administered for diseases of the thyroid: a survey of disposable gloves and preferably, flushed down the toilet; physicians and allied practioners. Thyroid 21:151-160.
gloves and nonflushable material, such as paper towels, 5. Kloos RT 2011 Survey of radioiodine therapy safety practices should be placed in the specified trash bag.
highlights the need for user-friendly recommendations.
(Editorial) Thyroid 21:47-48.
6. U.S. Nuclear Regulatory Commission Regulatory Guide 8.39 bags must be leak proof. These bags containing waste can be 1997 Release of patients administered radioactive materials.
returned to the Nuclear Medicine facility after 1 to 2 weeks, as Available at www.nucmed.com/nucmed/ref/8_39.pdf, ac- determined by the respective treatment personnel. Otherwise the bags should be tightly closed and stored in a secure place 7. Howe DB, Beardsley M, Baksh SR 2008 NUREG 1556 Con- at least 6 feet away from people and animals. The bags can be solidated guidance about medical licensure. Program- taken to the usual household trash disposal sites after 80 days specific guidance about medical use licenses. Appendix U pg (10 half lives of 131I) at which time radiation detectors should U-1 and Supplement B pg U-21-23. Available at www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1556/v9/ 8. Grigsby PW, Siegel BA, Baker S, Eichling JO 2000 Radiation exposure from outpatient radioactive iodine (131I) therapy Two major principles guide radiation safety: sound medi- for thyroid carcinoma. JAMA 283:2272-2274.
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24. Brzozowska M, Roach PJ 2006 Timing and potential role of diagnostic I-123 scintigraphy in assessing radioiodine breast This article has been revised since its original release in the April 2011 issue of Thyroid. Changes made subsequent to the April 2011 printing are presented in boldface. Correction date: May 19, 2011.
This article has been cited by:
1. Elizabeth N. Pearce , James V. Hennessey , Michael T. McDermott. 2011. New American Thyroid Association and American Association of Clinical Endocrinologists Guidelines for Thyrotoxicosis and Other Forms of Hyperthyroidism: Significant
Progress for the Clinician and a Guide to Future ResearchNew American Thyroid Association and American Association of
Clinical Endocrinologists Guidelines for Thyrotoxicosis and Other Forms of Hyperthyroidism: Significant Progress for the
Clinician and a Guide to Future Research. Thyroid 21:6, 573-576. [] [] []

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