甲状腺扫描

定义

A thyroid scan uses a radioactive iodine tracer to examine the structure and function of the thyroid gland. This test is often done together with a 放射性碘吸收试验.

选择的名字

Scan - thyroid; Radioactive iodine uptake and scan test - thyroid; Nuclear scan - thyroid; Thyroid nodule - scan; Goiter - scan; Hyperthyroidism - scan

如何执行测试

测试是这样完成的:

• You are given a pill that contains a tiny amount of radioactive iodine. After swallowing it, you wait as the iodine collects in your thyroid.
• The first scan is usually done 4 to 6 hours after you take the iodine pill. Another scan is usually done 24 hours later. During the scan, you lie on your back on a movable table. Your neck and chest are positioned under the scanner. You must lie still so that the scanner gets a clear image.

The scanner detects the location and intensity of the rays given off by the radioactive material. A computer displays images of the thyroid gland. Other scans use a substance called technetium instead of radioactive iodine.

如何准备考试

Follow instructions about not eating before the test. You may be told not to eat after midnight before your scan the next morning.

Tell your health care provider if you are taking anything that contains iodine because it may affect your test results. This includes some medicines, including thyroid drugs and heart medicines. Supplements such as kelp also contain iodine.

如果你有以下情况，也要告诉你的欧洲杯竞猜app:

• Diarrhea (may decrease absorption of the radioactive iodine)
• Had recent CT scans using intravenous iodine-based contrast (within the past 2 weeks)
• Too little or too much iodine in your diet

Remove jewelry, dentures, or other metals because they may interfere with the image.

考试的感觉如何

Some people find it uncomfortable to stay still during the test.

为什么要进行测试

这个测试是为了:

• 评估甲状腺结节或 甲状腺肿
• 找出问题的原因 甲状腺过度活跃
• Check for thyroid cancer (rarely, since other tests are more accurate for this)

正常的结果

Normal test results will show that the thyroid appears to be the correct size, 形状, 在合适的位置. It is an even gray color on the computer image without darker or lighter areas.

异常结果意味着什么

A thyroid that is enlarged or pushed off to one side could be a sign of a 肿瘤.

Nodules absorb more or less iodine and this will make them look darker or lighter on the scan. A nodule is usually lighter if it has not taken up the iodine (often called a 'cold' nodule). If part of the thyroid appears lighter, it could be a thyroid problem. Nodules that are darker have taken up more iodine (often called a 'hot' nodule). They can be overactive and may be the cause of an overactive thyroid.

The computer will also show the percentage of iodine that has collected in your thyroid gland (radioiodine uptake). If your gland collects too much iodine, it may be due to an overactive thyroid. If your gland collects too little iodine, it may be due to inflammation or other damage to the thyroid.

风险

All radiation has possible side effects. The amount of radioactivity is very small, and there have been no documented side effects.

Women who are pregnant or breastfeeding should not have this test.

Talk to your provider if you have concerns about this test.

注意事项

The radioactive iodine leaves your body through your urine. You should not need to take special precautions, 如小便后冲洗两次, for 24 to 48 hours after the test because the dose of radioactive iodine is very low. Ask your provider or the radiology/nuclear medicine team performing the scan about taking precautions.

参考文献

布卢姆米. 甲状腺显像. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. 内分泌学:成人和儿童. 7日艾德. Philadelphia, PA: Elsevier Saunders; 2016:chap 79.

Salvatore D, Cohen R, Kopp PA, Larsen PR. Thyroid pathophysiology and diagnostic evaluation. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. 威廉斯内分泌学教科书. 14日艾德. Philadelphia, PA: Elsevier; 2020:chap 11.