{"id":3409779,"date":"2022-04-12T22:12:00","date_gmt":"2022-04-13T02:12:00","guid":{"rendered":"https:\/\/myendoconsult.com\/learn\/?p=3409779"},"modified":"2023-03-16T05:34:10","modified_gmt":"2023-03-16T10:34:10","slug":"radioactive-iodine-uptake-and-scan","status":"publish","type":"post","link":"https:\/\/myendoconsult.com\/learn\/radioactive-iodine-uptake-and-scan\/","title":{"rendered":"Radioactive Iodine Uptake and Scan"},"content":{"rendered":"

Radioactive iodine uptake and scan for the thyroid is a test that measures the amount of radioactive iodine absorbed by the thyroid gland. It is used in the diagnosis of thyroid cancer and other disorders of the thyroid gland.<\/p>\n

\"\"<\/p>\n

Indications and Contraindications<\/h2>\n
    \n
  1. Thyroid imaging is useful in, but not limited to the evaluation of:<\/li>\n
  2. Size and location of thyroid tissue.<\/li>\n
  3. Productive or Destructive hyperthyroidism.<\/li>\n
  4. Suspected focal (i.e., masses) or diffuse thyroid disease.<\/li>\n
  5. The risk for thyroid neoplasm (e.g., post neck irradiation).<\/li>\n<\/ol>\n

    Thyroid uptake is also useful for:<\/strong><\/p>\n

      \n
    1. Distinguishing between productive hyperthyroidism from other forms of thyrotoxicosis (e.g., thyroiditis and thyrotoxicosis factitia).<\/li>\n
    2. Estimating the dose of iodine-131 to be administered for patients undergoing treatment for hyperthyroidism<\/li>\n<\/ol>\n

      Examination Time (2 day test)(estimated time to complete exam)<\/em><\/strong><\/p>\n

        \n
      1. Initially \u2013 20 minutes for radiopharmaceutical administration. (Day 1)<\/li>\n
      2. Optional 4 hour uptake \u2013 15 minutes (Day 1)<\/li>\n
      3. Imaging and uptake at 24 hours \u2013 1 hour. (Day 2)<\/li>\n<\/ol>\n

        Patient Preparation<\/em><\/strong><\/p>\n

        The patient must be off thyroid hormones per physician direction as follows.<\/p>\n

        (1) Thyroxine (T4) for at least 1 month. Levothyroxine (Synthroid). * Thyroid cancer risk stratification<\/p>\n

        (2) Triiodothyronine (T3) for at least 10 days. Liothyronine sodium (Cytomel). * Thyroid cancer risk stratification<\/p>\n

        The patient must not be taking anti-thyroid medications.<\/p>\n

        (1)\u00a0 Propylthiouracil (PTU) and methimazole (Tapazole) for at least 10 days.<\/p>\n

        The patient must not have been exposed to intravenous or intrathecal iodinated contrast material (IVP, CT with contrast, myelogram angiogram) for at least 1 month (non-ionic) before the RAIU scan.<\/p>\n

        Equipment and Energy Windows<\/em><\/strong><\/p>\n

        Gamma Camera: 1 large field of view<\/p>\n

        Capintec probe\u2014measures thyroid function<\/p>\n

          \n
        1. Collimator \u2013 pinhole with 5 millimeter insert<\/li>\n
        2. Energy Window: 20% window centered at 159 kiloelectron volt (kev)<\/li>\n<\/ol>\n

          Radiopharmaceutical Dose and Technique of Administration.<\/em><\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/em><\/strong><\/p>\n\n\n\n\n
          Study<\/p>\n

          (Protocol Category)<\/td>\n

          		Prescribed (Rx) Dose<\/td>\nAdministered Dose Range<\/p>\n

          +\/- 10%<\/td>\n

          		Radiopharmaceutical<\/td>\nMethod of Administration<\/td>\n<\/tr>\n
          I-123 Uptake and Scan<\/td>\n200 microcurie (uCi)<\/td>\n180 uCi to 220 uCi<\/td>\nSodium Iodide I-123<\/td>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Oral<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

          Patient Position and Imaging Field<\/em><\/strong><\/p>\n

            \n
          • Patient Position: Supine<\/li>\n
          • Image Field: neck<\/li>\n<\/ul>\n

            Acquisition Protocol<\/u><\/strong><\/h2>\n
              \n
            1. Uptake portion to determine thyroid function is done at an optional of four hours if requested by physician after ingestion of capsules and always done at 24 hours post ingestion also.\u00a0 Print out computer results of uptake percentage.<\/li>\n
            2. Begin imaging with gamma camera 24 hours after ingestion of the radiopharmaceutical.<\/li>\n
            3. Select patient name and make sure protocol is called I-123 Uptake and Scan<\/strong> and the accession number is correct. \u00a0\u00a0\u00a0\u00a0\u00a0 <\/em><\/strong><\/li>\n
            4. Acquire a 10 \u2013 minute Anterior Marker image of the thyroid with the collimator 6 centimeters (cm) from the patient\u2019s neck (a 5 cm long block can be made as a convenient measuring device). Markers (source I-123 capsule) should be placed in the field of view to calibrate the image for size (at sternal notch and 5 cm to the right).<\/li>\n
            5. Acquire a second 10 \u2013 minute Anterior image with the distance between the collimator and patient\u2019s neck is then adjusted so that the thyroid gland fills three quarters of the field of view.<\/li>\n
            6. Acquisition of 10 \u2013 minute \u201cRAO\u201d and \u201cLAO\u201d oblique images at 35 degrees and again with the thyroid gland \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 filling approximately three-quarters of the field of view.<\/li>\n<\/ol>\n

              Physical Half-Life = 13.2 hours<\/p>\n

              \u00a0<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0 Radiation\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/u>\u00a0Mean % per disintegration\u00a0\u00a0\u00a0\u00a0\u00a0 <\/u>\u00a0Mean energy (keV)<\/u><\/p>\n

              Gamma-2\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 83.3\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 159.0<\/p>\n

              Ce-K, gamma-2\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 13.6\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 127.2<\/p>\n

              Patient instructions for a RAIU scan<\/h2>\n

              How do I get ready for the test?<\/strong><\/p>\n

              You should be off all thyroid medication six weeks before your<\/p>\n

              appointment. You should not have a CT Scan with any contrast or x-ray dye for six weeks before your procedure.<\/p>\n

              Women who are pregnant or breast-feeding should not have this test done.<\/p>\n

              How is this test done?<\/strong><\/p>\n

              This is a two-day procedure.<\/p>\n

              First day<\/strong><\/p>\n

              On your first day, the nuclear medicine technologist will give you two pills that contain a small amount of radioactive iodine. This iodine will travel to your thyroid over the next 24 hours. You will not feel any different from these capsules. The first day you are here for about 15 minutes.<\/p>\n

              What to avoid<\/strong><\/p>\n

              The only restriction you will have over the next 24 hours is to avoid certain foods that contain extra iodine. Examples are seafood, strawberries, white bread, and foods with large amounts of extra salt.<\/p>\n

              Second day<\/strong><\/p>\n

              When you return the next day we will take pictures of your thyroid. You will be asked to lie on your back on our imaging table. We will take four pictures of your thyroid, each taking about 10 minutes. You will be asked to lie very still as this is important in getting quality images. The second day will take about one hour.<\/p>\n

              What can I expect after the procedure?<\/strong><\/p>\n

              There should be no ill effects during or after the exam. The dose of radioactive material you will receive is very small.<\/p>\n

              When do I hear the results?<\/strong><\/p>\n

              After reading your nuclear medicine scan, the radiologist will give a report to your doctor. Your doctor will discuss the results with you by phone, by letter or at the time of your next office visit.<\/p>\n

              Questions?<\/strong><\/p>\n

              Call your doctor if you have questions about your medicines.<\/p>\n

              References<\/h2>\n
                \n
              • Society of Nuclear Medicine (SNM) Procedure Guideline for Thyroid Scintigraphy 3.0,Balon, September,2006.<\/li>\n
              • Image Wisely Radiation Safety Clinical Aspects of General Nuclear Medicine, Administered Activity and Patient Radiation Exposure, Becker, Nov 2012<\/li>\n
              • Pediatric Radiopharmaceutical Administered Doses: 2010 North American Consensus Guidelines, Gelfand, Feb, 2011 JMNM<\/li>\n
              • United States Nuclear Regulatory Commission US NRC 10 CFR 35.63Textbook of Nuclear Medicine, Wilson, 1997.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

                Radioactive iodine uptake and scan for the thyroid is a test that measures the amount of radioactive iodine absorbed by the thyroid gland. It is used in the diagnosis of thyroid cancer and other disorders of the thyroid gland. Indications and Contraindications Thyroid imaging is useful in, but not limited to the evaluation of: Size […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-3409779","post","type-post","status-publish","format-standard","hentry","category-uncategorized","post-wrapper","thrv_wrapper"],"_links":{"self":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/posts\/3409779","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/comments?post=3409779"}],"version-history":[{"count":24,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/posts\/3409779\/revisions"}],"predecessor-version":[{"id":4415821,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/posts\/3409779\/revisions\/4415821"}],"wp:attachment":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/media?parent=3409779"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/categories?post=3409779"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/tags?post=3409779"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}