frank p. dawry therapy of hyperthyroid thyroid disease with iodine-131

Frank P. DawryFrank P. Dawry

Therapy of Hyperthyroid Therapy of Hyperthyroid Thyroid Disease with Thyroid Disease with

Iodine-131Iodine-131


HyperthyroidismHyperthyroidismoveractivity of the thyroid glandoveractivity of the thyroid gland

Graves’ disease (Diffuse Toxic Goiter)Graves’ disease (Diffuse Toxic Goiter) Most commonMost common Autoimmune – thyroid stimulating antibodies interact with Autoimmune – thyroid stimulating antibodies interact with

TSH-receptor sites on thyroid follicular cell membrane to TSH-receptor sites on thyroid follicular cell membrane to increase synthesis and secretion of thyroid hormonesincrease synthesis and secretion of thyroid hormones

Characteristics of Graves DiseaseCharacteristics of Graves Disease Graves Disease effects women much more often than men Graves Disease effects women much more often than men

(about 8:1 ratio, thus 8 women get Graves Disease for every (about 8:1 ratio, thus 8 women get Graves Disease for every man that gets it).man that gets it).

Graves Disease is often called diffuse toxic goiter because Graves Disease is often called diffuse toxic goiter because the entire thyroid gland is enlarged, usually moderately the entire thyroid gland is enlarged, usually moderately enlarged, sometimes quite big. enlarged, sometimes quite big.

Graves disease is uncommon over the age of 50 (more Graves disease is uncommon over the age of 50 (more common in the 30's and 40's)common in the 30's and 40's)

Graves Disease tends to run in families (not known why)Graves Disease tends to run in families (not known why)


HyperthyroidismHyperthyroidismoveractivity of the thyroid glandoveractivity of the thyroid gland

Toxic Nodular Goiter (Plummer’s disease)Toxic Nodular Goiter (Plummer’s disease) Less frequentLess frequent Thyroid hormone secretion by autonomous areas of Thyroid hormone secretion by autonomous areas of

increased function within the thyroid glandincreased function within the thyroid gland

Thyroiditis (Inflammation of the thyroid gland)Thyroiditis (Inflammation of the thyroid gland) SubacuteSubacute Hashimoto’s - autoimmuneHashimoto’s - autoimmune


Single ‘Hot’ noduleSingle ‘Hot’ nodule


Common symptoms and Common symptoms and signs of hyperthyroidismsigns of hyperthyroidism

PalpitationsPalpitationsHeat intoleranceHeat intoleranceNervousnessNervousnessInsomniaInsomniaBreathlessnessBreathlessnessIncreased bowel movementsIncreased bowel movementsLight or absent menstrual Light or absent menstrual periodsperiodsFatigueFatigue

Fast heart rateFast heart rate Trembling hands Trembling hands Weight loss Weight loss Muscle weakness Muscle weakness Warm moist skin Warm moist skin Hair loss Hair loss Staring gaze Staring gaze


Feedback mechanismFeedback mechanism


Common tests used to Common tests used to diagnose hyperthyroidismdiagnose hyperthyroidism

Thyroid stimulating hormone (TSH) Thyroid stimulating hormone (TSH) Produced by the pituitary glandProduced by the pituitary gland decreased in hyperthyroidismdecreased in hyperthyroidism

Thyroid hormones themselves (T3, T4)Thyroid hormones themselves (T3, T4) will be increased will be increased

Iodine thyroid scanIodine thyroid scan will show if the cause is a single nodule or the will show if the cause is a single nodule or the

whole gland whole gland


TREATMENT OPTIONS FOR TREATMENT OPTIONS FOR HYPERTHYROIDISMHYPERTHYROIDISM

Anti-Thyroid Drugs - Anti-Thyroid Drugs - methimazole and propylthiouracil (PTU)methimazole and propylthiouracil (PTU)

interfere with the thyroid gland's ability to make its hormones interfere with the thyroid gland's ability to make its hormones Not a permanent cure Not a permanent cure

*Radioactive Iodine Treatment*Radioactive Iodine Treatment

thyroid cells will be damaged or killedthyroid cells will be damaged or killed takes one to two months before the thyroid has been killed takes one to two months before the thyroid has been killed

*Surgical Removal of the Gland or Nodule *Surgical Removal of the Gland or Nodule - Lobectomy or Thyroidectomy - Lobectomy or Thyroidectomy (partial or total)(partial or total)

less frequent useless frequent use Single noduleSingle nodule Radioiodine refusedRadioiodine refused Anti-thyroid drugs contraindicatedAnti-thyroid drugs contraindicated

Associated morbidity and mortalityAssociated morbidity and mortality

* Often results in hypothyroidism* Often results in hypothyroidism


Hyperthyroid therapyHyperthyroid therapy

Traditionally <30mCi of I-131 in order to avoid regulatory hospitalizationTraditionally <30mCi of I-131 in order to avoid regulatory hospitalization No longer the case since newer NRC release regulations stipulating <500 mrem No longer the case since newer NRC release regulations stipulating <500 mrem

to other individuals criteriato other individuals criteria

Fixed Millicurie administrationFixed Millicurie administration Graves’ disease 5-10 mCiGraves’ disease 5-10 mCi Nodular disease 10-29 mCiNodular disease 10-29 mCi

Delivered microcuries per gram Delivered microcuries per gram 55 to 160 uCi/gram (Graves’ disease)55 to 160 uCi/gram (Graves’ disease) 200 uCi/gram (Single Hyperfunctioning autonomous nodule)200 uCi/gram (Single Hyperfunctioning autonomous nodule)

Administered uCi = uCi/gram desired x gland weight (g) x 100/24 hour % uptakeAdministered uCi = uCi/gram desired x gland weight (g) x 100/24 hour % uptake

Delivered Rad – deliver precise radiation doseDelivered Rad – deliver precise radiation dose >120 Gy (Graves’ disease)>120 Gy (Graves’ disease) 300-400 Gy (Single Hyperfunctioning autonomous nodule)300-400 Gy (Single Hyperfunctioning autonomous nodule)

Administered uCi =Administered uCi = Rad desired ( x gland weight (g) x 100/24 hour % uptake x 93)Rad desired ( x gland weight (g) x 100/24 hour % uptake x 93)


Radiopharmacy Radiopharmacy Oral administration of I-131 sodium iodide Oral administration of I-131 sodium iodide

capsule or liquidcapsule or liquid ContraindicationsContraindications

Allergy to IodineAllergy to Iodine Pregnancy and/or nursingPregnancy and/or nursing

Serum pregnancy testSerum pregnancy test

Mechanism of actionMechanism of action Cellular damage caused by the 606keV Beta Cellular damage caused by the 606keV Beta

particle causing chromosomal destructionparticle causing chromosomal destruction


Beta Particle TherapyBeta Particle Therapy


Patient PreparationPatient Preparation

Prior to administrationPrior to administration Identify patientIdentify patient Verify doctor’s ordersVerify doctor’s orders Explain the procedureExplain the procedure Patient off of thyroid medications for at least 2 Patient off of thyroid medications for at least 2

daysdays Ensure that no iodinated radiographic studies Ensure that no iodinated radiographic studies

within the past 3 weekswithin the past 3 weeks Ensure that a negative result to a Ensure that a negative result to a recentrecent serumserum

pregnancy test has been received!pregnancy test has been received!


Patient PreparationPatient Preparation A written consent form should be obtained and A written consent form should be obtained and

should mention the following items:should mention the following items: that more than one I-131 treatment may be necessarythat more than one I-131 treatment may be necessary the risk of eventual hypothyroidism is high, especially the risk of eventual hypothyroidism is high, especially

after treatment of Graves’ diseaseafter treatment of Graves’ disease lifelong daily ingestion of a thyroid hormone tablet would lifelong daily ingestion of a thyroid hormone tablet would

be necessarybe necessary long-term follow-up will be necessarylong-term follow-up will be necessary ophthalmopathy may worsen or developophthalmopathy may worsen or develop rarely, there can be transient neck soreness or rarely, there can be transient neck soreness or

exacerbation of hyperthyroid symptoms secondary to exacerbation of hyperthyroid symptoms secondary to radiation thyroiditisradiation thyroiditis


Patient PreparationPatient Preparation

After administration discharge instructionsAfter administration discharge instructions Instruct patient to avoid close contact with anyone for 48 Instruct patient to avoid close contact with anyone for 48

hourshours Instruct patient not to share food or utensils – Instruct patient not to share food or utensils – do not use do not use

disposable plates and utensilsdisposable plates and utensils Flush two to three timesFlush two to three times Wash clothes and linens separately – double rinseWash clothes and linens separately – double rinse Inform patient that they may feel a scratchy throatInform patient that they may feel a scratchy throat Inform patient that the effect may be delayed for a week or Inform patient that the effect may be delayed for a week or

moremore Instruct patient to contact the department immediately if Instruct patient to contact the department immediately if

dose is vomited*dose is vomited*

*the patient ideally should remain in the department for one hour following *the patient ideally should remain in the department for one hour following administrationadministration


BioassayBioassay

Florida State Regulation: 64E-5.625 Safety Florida State Regulation: 64E-5.625 Safety Instruction and Precautions for Instruction and Precautions for Radiopharmaceutical Therapy, Brachytherapy, Radiopharmaceutical Therapy, Brachytherapy, and Teletherapy.and Teletherapy. measure the thyroid burden of each individual who measure the thyroid burden of each individual who

helped prepare or administer a dosage of helped prepare or administer a dosage of liquidliquid iodine 131 within 3 days after administering the iodine 131 within 3 days after administering the dosage.dosage.

Nuclear Regulatory Commission, Part 35Nuclear Regulatory Commission, Part 35 requires that, for staff who helped prepare or requires that, for staff who helped prepare or

administer a dosage of 131I to patients who were administer a dosage of 131I to patients who were hospitalized for compliance with the patient-release hospitalized for compliance with the patient-release criteria, a measurement of thyroid burden must be criteria, a measurement of thyroid burden must be made within three days of such administration.made within three days of such administration.

frank p. dawry therapy of hyperthyroid thyroid disease with iodine-131

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