Thyroid Nodules - Pediatric Thyroid Center at CHILDRENS HOSPITAL OF PHILADELPHIA

FINE NEEDLE ASPIRATION BIOPSY OF THE THYROID GLAND

THYROID SCAN
​THYROID UPTAKE AND SCAN
 
What is a Thyroid Uptake and Scan?
A nuclear medicine thyroid uptake and scan is a 2-day test. A thyroid uptake measures overall thyroid gland function. A thyroid scan shows the structure, size and location of your thyroid and the function of various portions of your gland. The first uptake will be done on day 1. You will come back the next day for another uptake and the scan. 

This procedure involves three visits to the Nuclear Medicine Department.
**Before the Test If you are taking thyroid medications or preparations that contain iodine, you may be asked to stop them for a time before this test.

Read this page to learn how to prepare for the test, how it works, how it is done, what you may feel during the test, and how to get your results. 



How Does the Uptake and Scan Work?
Uptake 
For the uptake, you will swallow a small dose of radioactive material (tracer). This tracer collects in your thyroid gland and gives off gamma and beta rays. A sensor will detect how much of the tracer your thyroid absorbs. 

Scan 
In the second part of the exam, a small amount of tracer is injected into a vein, usually in your arm. Images of your thyroid are then taken with a camera.
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How Do I Prepare?
6 Weeks Before
  • You must NOT have had X-ray exams involving iodine contrast (such as IVP or CT) in the last 6 weeks. .
4 Weeks Before
  • Most people will stop taking thyroid hormone medicine (synthroid, cytomel, lerothyroxine, lithyronine) 4 weeks before their exam. Check with your doctor before you stop taking this medicine.
In the Week Before
  • Do not take any oral iodides (such as Lugol’s solution or SSKI) for 5 days before your exam. Remain off them until exams are completed.
  • Do not take vitamins that contain iodine for 5 days before your exam.
  • Most people will stop taking anti-thyroid hormones, Propothyouracil (PTU), Methimazole, or Tapazole thyroid medicine 4 days before their exam. Be sure to check with your doctor before you stop taking these medicines.

Check with your physician regarding the timing of your medications (see guidelines below).
If you are diabetic, please consult with your doctor before you change your diet or medication.

Medication Hold Time
Methimazole (Tapazole) 1 week
Propylthiouracil (PTU) 1 week
Triiodothyronine [Liothyronine (generic), Cytomel (brand name), Triostat (brand name)] 2 weeks
Thyroxine [T4, levothyroxine (generic), Synthroid (brand name), Levoxyl (brand name)] 4 weeks
Amiodarone 6 months
Multivitamins 2 weeks
Topical iodine 4 weeks
IV contrast 2 weeks
Lithium 6 weeks
**Source:  ACR‐SNM‐SPR Practice Guidelines 2009 and SNM Procedure Guideline 2006


On the Day of the Test
  • Nothing to eat/drink from midnight, the night before the study.
  • Bring 2 forms of identification (ID) with you to the scan.
  • Avoid large meals two hours after your scheduled test.
  • You may take medications prescribed by your doctor before the test.
  • Check with ordering physician regarding medications that he/she may allow you to continue.
  • Please arrive 30 minutes prior to your appointment time.
  • If you are pregnant or think you may be pregnant please advise the technologist.
  • You must tell us if you are pregnant, even if you plan to end the pregnancy. If you might receive Iodine-131 (I-131) therapy after the uptake and scan and you are a female of childbearing age, we may send you for a pregnancy blood test on Day 1 of the exam. Plan to be here 1½ extra hours to get the results of the pregnancy test.
  • Tell us if you are currently breastfeeding. You cannot continue to breastfeed after you receive the radioactive tracers.

During the Test:

What should I expect during and after the exam?
  • It may be hard for some patients to lie still on the exam table.
  • Most of the tracer passes out of your body in your urine. The rest simply goes away over time

On Day 1-
  • You will be asked to swallow a small amount of radioactive iodine in a capsule. This part of the visit should take about fifteen minutes.
  • You can eat normally two hours after you take the capsule.
  • Approximately 4 hours later, you will return for the first measurement of uptake and the scan which will take approximately 1-hour.

For the scan, you will lie on your back on an imaging table with the camera positioned above you. We will take several images of your thyroid. Each image takes ten minutes.

On Day 2-
  • You will return for the remainder of the uptake procedures, which will take 5 minutes.
  • After this second uptake measurement, you will have a thyroid scan.
  • For the thyroid scan, a tracer will be injected in your vein. You will then need to wait 10 to 15 minutes before imaging begins. The entire visit takes about 1 to 1½ hours.
  • The uptake procedure measures the absorption of the radioactive iodine by your thyroid gland. As you sit comfortably in a chair, a thyroid probe will be positioned some inches from your neck, and several counts will be recorded
  • If you are going to be treated with a therapeutic dose of I31 after the 24-hour uptake and scan, do not eat any solid foods for 2 hours before this appointment. Treatment with I131 will add 1 more hour to your appointment time.
  • After the uptake and scan, it will take about 1 hour for your therapy dose to arrive.
  • If you will be treated with a therapeutic I131 dose after the uptake and scan, please review the radiation safety information. See “Instructions for Patients Receiving Radioactive Iodine Therapy for Hyperthyroidism.”

How Safe Is This Procedure?
Nuclear medicine procedures are very safe. The radioactive material is cleared quickly from your body. With a normally functioning thyroid gland, the whole body radiation dose is 0.03 rem, which is less than most routine X-ray procedures.

After your test-
The radiologist and technologist will not be able to give you results after your test is completed. A report will be sent to the doctor who ordered your test within one to two business days. Your doctor will share the results with you.
Thyrogen SCAN:
DOSING & ADMINISTRATION

Ablation ScheduleDay 1 : First Thyrogen Injection
Day 2 : Second Thyrogen Injectio
Day 3 Start radiation precautionsA whole-body scan may be performed
Day 6-10  - 3-7 days after the administration of radioiactive iodine therapy  

Scanning and Thyroglobulin Diagnostic Testing Schedule
Day 1 First Thyrogen Injection
Day 2 Second Thyrogen Injection
Day 3 Radioactive iodine scanning dose (for whole body scan) 
Day 5 Blood test for thyroglobulin Whole-body scan
Thyroglobulin Only Testing ScheduleDay 1 First Thyrogen Injection
Day 2 Second Thyrogen Injection
Day 5 Blood test for thyroglobulin W
*0.9 mg intramuscular injection to the buttock
The mean apparent elimination half-life was 25 ± 10 hours. There is no requirement to measure TSH when using Thyrogen.
Click here to download the printable version of the schedule to use with patients.


Thyrogen® (thyrotropin alfa for injection) 0.9 mg/mL after reconstitution
INDICATIONS AND USAGEThyrogen is a thyroid stimulating hormone indicated for:
Diagnostic: Use as an adjunctive diagnostic tool for serum thyroglobulin (Tg) testing with or without radioiodine imaging in the follow-up of patients with well-differentiated thyroid cancer who have previously undergone thyroidectomy.
Limitations of Use:
  • Thyrogen -stimulated Tg levels are generally lower than, and do not correlate with Tg levels after thyroid hormone withdrawal.
  • Even when Thyrogen -Tg testing is performed in combination with radioiodine imaging, there remains a risk of missing a diagnosis of thyroid cancer or underestimating the extent of the disease.
  • Anti-Tg Antibodies may confound the Tg assay and render Tg levels uninterpretable.
Ablation: 
Use as an adjunctive treatment for radioiodine ablation of thyroid tissue remnants in patients who have undergone a near-total or total thyroidectomy for well-differentiated thyroid cancer and who do not have evidence of distant metastatic thyroid cancer.
Limitations of Use:
  • The effect of Thyrogen on long term thyroid cancer outcomes has not been determined.
IMPORTANT SAFETY INFORMATIONWARNINGS AND PRECAUTIONS
There have been reports of death in non-thyroidectomized patients and in patients with distant metastatic thyroid cancer in which events leading to death occurred within 24 hours after administration of Thyrogen.
Caution should be exercised in patients who have substantial thyroid tissue still in situ or functional thyroid cancer metastases, specifically in the elderly and those with a known history of heart disease.
Hospitalization for administration of Thyrogen and post-administration observation in patients at risk should be considered.
There are post marketing reports of stroke in young women with risk factors for stroke, and neurological findings suggestive of stroke (e.g., unilateral weakness) occurring within 72 hours of Thyrogen administration in patients without known central nervous system metastases.
Patients should be well-hydrated prior to treatment with Thyrogen.
Sudden, rapid and painful enlargement of residual thyroid tissue or distant metastases can occur following treatment with Thyrogen.
Pretreatment with glucocorticoids should be considered for patients in whom tumor expansion may compromise vital anatomic structures.

ADVERSE REACTIONS
The most common adverse reactions reported in clinical trials were nausea and headache.
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USE IN SPECIFIC POPULATIONS:

Pregnancy Category C: 
Animal reproduction studies have not been conducted with Thyrogen. It is also not known whether Thyrogen can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. Thyrogen should be given to a pregnant woman only if clearly needed.
Nursing Mothers: 
It is not known whether the drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Thyrogen is administered to a nursing woman.
Pediatric Use: 
Safety and effectiveness in pediatric patients have not been established.
Geriatric Use: 
Results from controlled trials do not indicate a difference in the safety and efficacy of Thyrogen between adult patients less than 65 years and those over 65 years of age.
Renal Impairment: 
​Elimination of Thyrogen is significantly slower in dialysis-dependent end stage renal disease patients, resulting in prolonged elevation of TSH levels.