I-131 Sodium Iodide for Thyroid Cancer Therapies, Slides of Pathophysiology

Download I-131 Sodium Iodide for Thyroid Cancer Therapies and more Slides Pathophysiology in PDF only on Docsity! UW Hospital & Clinics – Madison, WI 53792 Nuclear Medicine Procedure REVISED: February 2020 Radiopharmaceutical Therapy: Agent/Protocol-Specific Procedure I-131 Sodium Iodide for Thyroid Cancer Therapies Remnant Ablation and Cancer Metastases Radiopharmaceutical Agent: I-131 Sodium Iodide I-131 sodium iodide is available as a stabilized aqueous solution or solid capsule form for oral administration. I-131 decays by beta emission (~90% of local irradiation) and associated gamma emission (~10% of local irradiation), with a physical half-life of 8.04 days. Sodium iodide is readily absorbed from the gastrointestinal tract. Following absorption, it is distributed primarily within the extracellular fluid of the body. It is concentrated and organified by the thyroid and trapped but not organified by the stomach and salivary glands. It is promptly excreted by the kidneys. Drug Information Source: FDA approved for hyperthyroidism and carcinoma of the thyroid. For additional information regarding this agent, consult package insert or other standard references Applicability of Worksheet: Clinical use of commercial product; standard of care Target Patient Process: Thyroid carcinoma patients in the initial post-thyroidectomy surgery phase, and post-thyroidectomy thyroid carcinoma patients with metastases (lymph node, pulmonary or skeletal) Written Directive and Validation: Authorized User will determine the appropriateness of the therapy, perform the necessary calculations, and complete the written directive as instructed on the Radiopharmaceutical Therapy Dose Documentation Form. Section B on the Radiopharmaceutical Therapy Dose Documentation Form “Patient Information/Education Verification” will be completed by the Authorized User prior to forwarding the Radiopharmaceutical Therapy Dose Documentation Form to Nuclear Pharmacy staff for drug procurement/preparation. Administration/Treatment Schedule: Patient Prep: Remnant Ablation: For patients whose thyroidectomy is suspected to be incomplete, a Tc99m-pertechnetate thyroid scan is recommended. See the Department of Radiology Nuclear Medicine Division Thyroid Scan Protocol for details regarding this procedure. If significant thyroid activity is visualized, then consider reducing the dose to prevent radiation tracheitis and esophagitis. Metastatic survey scans are generally not performed prior to the postoperative ablation therapy (thyroid stunning possible after 6 mCi I-131 scan dose). The original histology/ pathology report must be obtained, together with the surgeon's operative report to assess the risk category (low, moderate, high) of the patient. Cancer Metastases: Uptake in identified regions or lesions should be quantitated via a metastatic survey scan. See the Department of Radiology Nuclear Medicine Division Metastatic Survey Scan Protocol for details regarding this procedure All Patients: Thyroid Stimulating Hormone (TSH) greater than 50 international units is preferred. Patients should be off thyroid hormone for at least 3-4 weeks and liothyronine (Cytomel) 2 weeks prior to therapy to ensure this. Note: Patients on Thyrotropin alpha (Thyrogen) do not need to be off of hormone. Female Patients (Age 10 to 55 years): Patients must have a pregnant test performed no greater than 24 hours prior to the administration. Patients must not be breast feeding or have ceased breast feed 3 to 6 months prior to therapy. The therapy is affected by certain medications, iodine agents (e.g. contrast dyes) and foods (e.g. seaweed, kelp, sushi, miso soup, carrageen thickeners, alginate wound care agents. A low iodine diet 10 to 14 days prior to the therapy is to be followed, and the patient should not have received any iodine contrast within the last 6 weeks. See Health Facts For You Low Iodine Diet for list of restrictions and suggested menus. See Radioactive Iodine Uptake Interactions document and Iodine Containing Foods document attached to the Department of Radiology Nuclear Medicine Division Thyroid Uptake Protocol for detailed lists. Treatment: Prior to administration, the Nuclear Medicine physician will obtain written informed consent, and explain the treatment options to the patient. They must determine that the patient understands these options and implications. The Nuclear Medicine physician will educate the patient regarding radiation safety issues associated with I-131 sodium iodide treatment. The Nuclear Medicine Physician will discuss the planned treatment with the administering clinician. Administering clinicians must comply with the Department of Radiology Nuclear Medicine Division Personnel Bioassay Thyroid Counts policy. Procedure: 1. Written directive is completed, and dose is prepared and administered as directed on the Radiopharmaceutical Therapy Dose Documentation Form. 2. Oral dose is given to patient in either capsule or liquid form. The Nuclear Medicine Faculty must be available when the dose is administered. 3. If a liquid form is given, the administration vessel should be sitting on a solid, sturdy surface for administration. Prior to administration, the Administering Clinician may add enough tap water to increase the volume, so the vessel is approximately half full. Water should be added with care to avoid overfilling. Place water in a disposable cup or a syringe and slowly add to glass tube. After the patient drinks the dose, water should be added two more times to rinse the vessel and ensure the entire dose was administered. The patient should keep their mouth on the straw, and the straw in the glass tube while the water is added to avoid any dripping of I-131 sodium iodide solution. 4. The following will be surveyed with a GM counter and disposed of appropriately by the Administering Clinician: (includes, but is not limited to) gloves, chucks, paper towels, sterile fields. 5. Dispose of contaminated supplies in a long-lived isotope waste container. 6. The administration area will be surveyed with a GM counter after the patient is discharged from area/department. Exposure Calculations/Release Criteria: Calculations must be completed as directed on the Radiopharmaceutical Therapy Dose Documentation Form in Section E: “I-131 Therapy Calculation & Justification Record for Exposure from the Patient”. The Administering Clinician should perform calculations and complete the form where indicated. Final dose calibrator assay should be used for all calculations. Estimated maximum dose to an individual exposed to the patient must not exceed 500 mrem (0.5 rem or 5 mSv).