Glossary of Abbreviations & Terms 

Many abbreviations and terms are used in the Thyroid Cancer community which may be new to you.  This is a list of some commonly seen abbreviations with brief explanations to help you navigate more easily.  See the Reference Links throughout these pages for links to more in depth definitions and descriptions.   Also see the ThyCa Glossary at
This is a work in progress

Patti Woodbury Kuvik, Vail AZ                                                        Reviewed 07 January 2017
General Terms/Abbreviations
Avid, iodine avid:  Thyroid cancer cells which are able to take up iodine to detect or treat remaining cancer cells after surgery are called “iodine-avid”. []

LID (Low Iodine Diet):

Metastasis (Mets):

PDQ (Physician’s Data Query):  NCI's comprehensive source of cancer information. It contains cancer information summaries on a wide range of cancer topics with specific PDQ lookup for different types of cancer. [NIH National Cancer Institute]

RAI (Radioactive Iodine, I-131):

Staging: Determining the size and extent of any tumor and if the cancer has spread (metastisized).  See

ThyCa (Thyroid Cancer or Carcinoma): See Includes:
  • PTC - Papillary Thyroid Cancer (may be together with FTC)
  • FTC - Follicular Thyroid Cancer (may be together with PTC)
  • MTC - Medullary Thyroid Cancer
  • ATC - Anaplastic Thyroid Cancer

TT (Total Thyroidectomy): 

Cytomel: see Liothyronine (T3)

Levothyroxine (T4): also known as L-thyroxine, is a synthetic thyroid hormone that is chemically identical to thyroxine (T4), which is naturally produced by the thyroid gland[Wikipedia]  The full effect may take a few weeks; long term T4 is longer acting (weeks) than T3 (days).
US brand names: Synthroid, Levothroid, Levoxyl, Unithroid, Levo-T, Tirosint
Canadian brand names: Synthroid, Eltroxin, PMS-Levothyroxine  

Liothyronine (T3): A synthetic form of thyroid hormone (T3) used to treat hypothyroidism. It is marketed as the sodium salt under the brand name Cytomel (or Tertroxin in Australia). [Wikipedia] Effects can be immediate; long termT3 is shorter acting (days) than T4 (weeks). Used alone or in combination with T4.

NDT (Natural Desiccated Thyroid): Natural preparations derived from porcine thyroid glands. They provide 38 mcg levothyroxine (T4) and 9 mcg liothyronine (T3) for each 65 mg (1 Grain) of the labeled content of thyroid.
US brand names: Armour Thyroid, WP Thyroid, Nature-Throid

LDN (Low-dose naltrexone): The off-label use of the medication naltrexone at low doses for diseases such as multiple sclerosis. Naltrexone is a strong opioid antagonist. [Wikipedia]

Mcg (microgram/s): one thousandth of a milligram
Mg (milligram/s): one thousandth of a gram
Grain:  an apothecary (medical) measurement equal to exactly 64.79891 milligrams (nominal 65 mg). Often used for NDT dosages.

Thyrogen: Recombinant human thyroid-stimulating hormone. []
Used as an alternative to withholding thyroid hormone replacement prior to RAI treatment after surgery.

TKI: Tyrosine kinase inhibitor. A class of drugs that drug that inhibits tyrosine kinases - which are enzymes responsible for the activation of many proteins. Numerous TKIs  have been proven to be effective anti-tumor and anti-leukemic agents.
Blood Tests
Thyroid Panel: evaluate thyroid gland function and to help diagnose thyroid disorders, evaluate therapy after thyroidectomy.  May include:

  • TSH (Thyroid Stimulating Hormone): part of the body's feedback system to maintain stable amounts of the thyroid hormones thyroxine (T4) and triiodothyronine (T3) in the blood and to help control the rate at which the body uses energy. Basic test used to monitor T4 (levothyroxine) replacement therapy In combination with Free T4 test.

  • Free T4 and Total T4: Free T4 is not affected by protein levels and is the active form of thyroxine. The free T4 test is thought to be a more accurate reflection of thyroid hormone levels than total T4.

  • Free T3 and Total T3: T4 is converted into T3 by the liver and other tissues as needed. Most of the T4 and T3 circulates in the blood bound to protein, while a small percentage is free (not bound). This will help evaluate if T4 is being appropriately converted to T3.

  • TgAb (Thyroglobulin antibody): Whenever a thyroglobulin test is performed to see if the antibody is present and likely to interfere with the test results (e.g., at regular intervals after thyroid cancer treatment)

  • Tg (Thyroglobulin): Primarily used as a tumor marker to evaluate the effectiveness of treatment for thyroid cancer and to monitor for recurrence. Not every thyroid cancer will produce thyroglobulin, but the most common types, the well-differentiated papillary and follicular thyroid cancers, frequently do, resulting in increased levels of thyroglobulin in the blood.

  • Calcitonin: The calcitonin test is primarily used to help diagnose C-cell hyperplasia and medullary thyroid cancer, to evaluate the effectiveness of treatment, and to monitor those affected for recurrence. Calcitonin is involved in the regulation of calcium levels in the blood however, its role in calcium regulation is minor compared with parathyroid hormone (PTH) and the measurement of calcitonin in blood is not useful for diagnosis of disorders of calcium regulation.

PTH (Parathyroid Hormone): PTH is a hormone which helps to regulate the amount of calcium in the blood. The test is used to evaluate parathyroid function, help diagnose the cause of a low or high calcium level and to help distinguish between parathyroid-related and non-parathyroid-related causes. The Parathyroid glands which produce PTH are sometimes damaged, temporarily “stunned” or may even be removed during thyroid surgery. []

Imaging and Procedures

Biopsy: Samplling of suspected nodule or tumor tissue to determine if cancer is present.
May be fine needle aspiration (FNA), surgical (incision or laproscopic) or by scoping the suspected organ (brochoscopy, endoscopy, etc.).Results used to determine type and staging of cancer tumors.

FDG (Fludeoxyglucose or fludeoxyglucose F 18, 18F-FDG): see PET Scan. [Wikipedia]

FNA (Fine Needle Aspiration): Biopsy procedure to determine if a thyroid nodule is benign or cancer.

PET Scan (Positron Emission Tomography, FDG-PET): A functional imaging technique that is used to detect cancer spread (metastasis) or reoccurrence for cancers. The uptake of 18F-FDG by tissues is a marker for the tissue uptake of glucose, which in turn is closely correlated with certain types of tissue metabolism. After 18F-FDG is injected into a patient, a PET scanner can form two-dimensional or three-dimensional images of the distribution of 18F-FDG within the body. [Wikipedia]

WBS (Whole Body Scan): Reference Links

Thyroidectomy Post-Surgical Issues
Swallowing Exercises: these can help alleviate the sensation of “choking” following thyroid and other neck/oral surgery.  

Basic Intro to T3, T4, FT3 and FT4 after Thyroidectomy - A blog by a biomedical engineer ThyCa member to help those who are doing poorly on replacement hormones after thyroidectomy but need a more science oriented guide on using T4 and T3, or natural thyroid (NDT). Additional discussion on various other associated issues. - Browse PDR's full list of drug information

Lab Tests Online - General information on a variety of lab tests. 

Herbs and Supplements: About Herbs - MSK Cancer Centers awesome searchable database. Find evidence-based information from our Integrative Medicine experts about herbs, vitamins, and other dietary supplements. (Also available as a mobile app)

Radioactive Iodine (RAI) Treatment

ThyCa page about Radioactive Iodine treatment - Preparation, low iodine diet, scans, possible side effects, etc.

National, International Organizations
NIH - National Cancer Institute
Publications - links including PDQ’s, Fact Sheets and Dictionaries

American Cancer Society

Inspire: ThyCa: Thyroid Cancer Survivors’ Association, Inc.
Discussion group

Cancer Treatment Centers
Although some centers are “prominent” or well known, there are too many good comprehensive centers to list all; check the NCI Designated Cancer Centers list.

National Cancer Institute Designated Cancer Centers - NCI-Designated Cancer Centers deliver cutting-edge cancer treatments to patients in communities across the United States. Find a center near you and learn about its patient services and research capabilities.