SNMMI Procedure Standard for Scintigraphy for Differentiated Thyroid Cancer

Article Figures & Data

TABLE 1

Representative Drugs/Supplements That Interfere With Radioiodine (in Alphabetical Order)

Name	Withdrawal time
Amiodarone	3–6 mo
Antitussives	2–4 wk
Bromides	1 wk
Iodinates ointments	2–4 wk
Levothyroxine (T4)	4–6 wk
Lugol’s solution	2–3 wk
Mineral/vitamin supplements	2–4 wk
Nitrates	1 wk
Perchlorate	1 wk
Potassium iodide	2–3 wk
Salicylates (large doses)	1 wk
Steroids	Variable
Sulfonamides	1 wk
Triiodothyronine (T3)	2–3 wk

TABLE 2

Summary of Information Pertinent to Performing the Procedure

Topic	Action/information needed
Radioiodine-interfering materials	Avoid and obtain history of (e.g., medications, intravenous contrast [especially as a part of a CT exam])
Iodine intake	Compliance with low-iodine diet
TSH	Appropriate TSH level
Stimulation	Preparation with THS versus rhTSH
Surgery	Surgical information (e.g., total/subtotal thyroidectomy vs. lobectomy, extent of cervical compartments dissected)
Histopathology	Information on presence/absence of capsular or angiolymphatic invasion, extrathyroidal extension, surgical margin status, presence/extent of lymph node metastases, and level of cervical compartments involved
Imaging	Results of prior scintigraphy or other pertinent imaging procedures
RAI treatments	Information on any prior RAI treatments
Physical	Physical exam findings
Menstruation/lactation	Menstrual and lactation history, negative serum pregnancy test before RAI administration if needed

TABLE 3

Radiation Dosimetry for Adults

Radiopharmaceuticals	Administered activity (MBq [mCi])	Organ Receiving largest radiation dose (mGy/MBq [rad/mCi])	Effective dose (mSv/MBq [rem/mCi])
¹⁸F-FDG	370–740 intravenously (10–20)	0.15 bladder wall (0.56)	0.019 (0.07)
Na¹²³I iodide (0% thyroid uptake)	74–148 by mouth (2–4)	0.097 bladder wall (0.36)	0.010 (0.039)
Na¹³¹I iodide (0% thyroid uptake)	37–148 by mouth (1–4)	0.66 bladder wall (2.4)	0.058 (0.21)

https://www.doseinfo-radar.com. Accessed August 18, 2020.
International Commission on Radiological Protection. Radiation Doses to Patients from Radiopharmaceuticals. New York, NY: Elsevier. 2008.
Delbeke D, Coleman RE, Guiberteau MJ, et al. Procedure guideline for tumor imaging with ¹⁸F-FDG PET/CT 1.0. J Nucl Med 2006;47:885–895.