Nuclear medicine thyroid scan
Informed by recognized medical guidance
Overview
A nuclear medicine thyroid scan is a safe imaging test that uses a very small amount of radioactive material to check how your thyroid gland looks and works. The thyroid is a butterfly-shaped gland in your neck that makes hormones to control your body’s metabolism.
Key facts
- The scan shows the size, shape, and position of your thyroid gland.
- It helps find problems like nodules (lumps), overactive or underactive thyroid, and thyroid cancer.
- The amount of radiation used is very low and leaves your body within a few days.
Yes, this scan is a standard test done in many hospitals worldwide. It is safe and well-tolerated.
It is used for people of all ages who have symptoms of a thyroid problem, an abnormal lump in the neck, or abnormal blood test results for thyroid hormones.
Symptoms
- Sudden trouble breathing or feeling like your throat is closing
- Chest pain or pressure
- Severe confusion or passing out
- Very fast or irregular heartbeat that does not go away
- ⚠A neck lump that grows quickly
- ⚠High fever with a fast heart rate in a person with known thyroid disease
- ⚠Severe headache or vision changes
Common symptoms
- A lump or swelling in the front of the neck
- Unexplained weight loss or weight gain
- Feeling very tired or weak
- Racing heart or palpitations
- Feeling too hot or too cold all the time
- Changes in mood, such as anxiety or depression
- Hoarse voice or trouble swallowing
Symptoms in children
- Slow growth or delayed puberty
- Poor school performance or trouble concentrating
- Increased energy or restlessness
- Unexplained weight changes
Symptoms in older adults
- Confusion or memory problems
- Falls or weakness
- Loss of appetite
- Heart rhythm problems
Causes
Main causes
- The scan is used to investigate possible thyroid conditions, but the causes of those conditions vary. For example, nodules can be caused by iodine deficiency, inflammation, or benign growths. Overactive thyroid can be caused by Graves' disease, a thyroid nodule that makes too much hormone, or inflammation. Underactive thyroid is often caused by an autoimmune disease (Hashimoto's thyroiditis) or previous treatments.
Risk factors
- Being female (thyroid problems are more common in women)
- Family history of thyroid disease
- Having an autoimmune disorder
- Exposure to radiation in the neck area
- Iodine deficiency or excess
When to see a doctor
See a doctor urgently if:
- If you have trouble breathing or swallowing due to a neck lump
- If you have sudden vision changes or bulging eyes
- If you experience severe weight loss, rapid heartbeat, or feeling very shaky
Book a routine appointment if:
- If you notice a new lump in your neck
- If you have ongoing symptoms like tiredness, weight changes, or feeling too hot or cold
- If your doctor finds abnormal thyroid blood tests
Diagnosis
A nuclear medicine thyroid scan is usually done after you have had blood tests or an ultrasound that suggest a problem. It helps your doctor see how the thyroid is working and find the cause of your symptoms.
Tests that may be done
- Blood tests to check thyroid hormone levels and antibodies
- Ultrasound to see the thyroid structure
- The thyroid scan itself: you swallow or get an injection of a small amount of radioactive tracer, then lie on a table while a special camera takes pictures of your thyroid
What to expect at your appointment
The test is painless and takes about 30 minutes. You may be asked to stop certain medications before the scan. After the scan, you can return to normal activities. The radioactive tracer leaves your body naturally in urine and stool over a day or two. Tell the technologist if you are pregnant or breastfeeding.
Treatment
Treatment depends on what the scan and other tests find. Many thyroid conditions can be managed with medication, lifestyle changes, or if needed, surgery. Your doctor will discuss the best plan for you.
Self-care at home
- Take any prescribed medications exactly as directed
- Eat a balanced diet with plenty of fruits, vegetables, and whole grains
- Get regular exercise as your energy allows
- Avoid smoking, as it can make thyroid eye disease worse
Medical treatments
Depending on the diagnosis, treatments may include medicines to adjust thyroid hormone levels, radioactive iodine therapy to shrink an overactive thyroid or treat certain thyroid cancers, or other medications to manage symptoms. Your healthcare team will explain your options and help you choose what is right for you.
When is surgery considered?
Surgery to remove part or all of the thyroid may be recommended if a nodule is suspicious for cancer, if a large goiter is causing breathing or swallowing problems, or if other treatments are not suitable.
Living with this condition
After the scan, you will get instructions on any necessary follow-up. Most people go back to normal activities right away. If you are diagnosed with a thyroid condition, you may need regular check-ups and blood tests to monitor your thyroid levels.
Lifestyle tips
- Maintain a healthy weight to support your metabolism
- Manage stress with relaxation techniques like deep breathing or gentle yoga
- Keep a symptom diary to share with your doctor
- Wear a medical alert bracelet if you take thyroid medication
Diet and exercise
Eat a variety of foods that support your overall health. Avoid high doses of iodine supplements unless your doctor advises them. Get moderate exercise like walking or swimming, but listen to your body if you feel tired.
Mental health and emotional wellbeing
Thyroid problems can affect your mood and energy. It is normal to feel anxious, depressed, or frustrated. Talk to your doctor if you have these feelings. Support from family, friends, or a counsellor can help.
Prevention
You cannot always prevent thyroid problems, but you can reduce risk by avoiding unnecessary radiation to the neck, eating a balanced diet with enough iodine, and seeing your doctor if you have a family history of thyroid disease.
Screening programmes
Routine screening is not recommended for everyone, but if you have symptoms or a strong family history, your doctor may suggest blood tests. The thyroid scan itself is not a screening test—it is used when a problem is already suspected.
Complications
If left untreated
- An overactive thyroid can cause heart problems, brittle bones, and eye issues
- An underactive thyroid can lead to high cholesterol, heart disease, and depression
- Thyroid nodules that are cancerous may spread if not treated
Long-term outlook
The good news is that most thyroid conditions are very treatable. With proper care, people with thyroid disease can lead full, healthy lives. The nuclear medicine thyroid scan is a safe and important tool to help your doctor find the right treatment for you.
Find support
International organisations
- Thyroid Federation International
Local organisations
- British Thyroid Foundation · United Kingdom
- Thyroid UK · United Kingdom
External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.
Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
Related conditions
Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 16, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.
Guidance may differ by country or region. Confirm local recommendations with a qualified healthcare provider.