PET扫描

定义

A positron emission tomography (PET) scan is a type of imaging test. It uses a radioactive substance called a tracer to look for disease in the body.

A PET扫描 shows how organs 和 tissues are working.

• 这和 核磁共振成像 和 CT 扫描. These tests show the structure of, 和 blood flow to 和 from organs.
• Machines that combine the PET 和 CT images, called a PET/CT, are commonly used.

选择的名字

正电子发射断层扫描; Tumor imaging - PET; PET/CT

如何执行测试

A PET扫描 uses a small amount of radioactive tracer. 示踪剂通过静脉(IV)给予。. The needle is most often inserted on the inside of your elbow. The tracer travels through your blood 和 collects in organs 和 tissues. This helps the radiologist see certain areas more clearly.

You will need to wait as the tracer is absorbed by your body. 这大约需要1个小时.

Then, you will lie on a narrow table that slides into a large tunnel-shaped scanner. PET检测来自示踪剂的信号. 计算机将信号转换成三维图像. The images are displayed on a monitor for your health care provider to read.

考试时你必须躺着不动. Too much movement can blur images 和 cause errors.

How long the test takes depends on what part of the body is being scanned.

如何准备考试

You may be asked not to eat anything for 4 to 6 hours before the scan. You will be able to drink water but no other beverages including coffee. If you have diabetes, your provider will tell you not to take your diabetes medicine before the test. 这些药会影响结果.

如果:

• You are afraid of close spaces (have claustrophobia). You may be given a medicine to help you feel sleepy 和 less anxious.
• 你怀孕了，或者觉得自己可能怀孕了.
• You have any allergies to injected dye (contrast).

Always tell your provider about the medicines you are taking. Let your provider know about the medicines you bought without a prescription. Sometimes, medicines may interfere with the test results.

考试的感觉如何

You may feel a sharp sting when the needle with the tracer is placed into your vein.

PET扫描不会引起疼痛. The table may be hard or cold, but you can request a blanket or pillow.

An intercom in the room allows you to speak to someone at any time.

There is no recovery time, unless you were given a medicine to relax.

为什么要进行测试

The most common use for a PET扫描 is for cancer, when it may be done:

• 看看癌症扩散到什么程度. 这有助于选择最佳的治疗方法.
• To check how well your cancer is responding, either during treatment or after treatment is completed.

此测试还可用于:

• Check brain function most often in people with symptoms of cognitive problems
• 确定癫痫在大脑中的来源
• 显示出存在的区域 流向心脏的血液不足
• 确定是否 你肺里的肿块是癌变的还是无害的

正常的结果

A normal result means there were no problems seen in the size, shape, or position of an organ. There are no areas in which the tracer has abnormally collected.

异常结果意味着什么

Abnormal results depend on the part of the body being studied. 异常结果可能是由于:

• 癌症
• 感染
• 器官功能问题

风险

The amount of radiation used in a PET扫描 is about the same amount as used in most CT 扫描. These 扫描 use short-lived tracers, so the radiation is gone from your body in about 2 to 10 hours. Having many x-rays, CT or PET扫描s over time may increase your risk for cancer. 然而，任何一次扫描的风险都很小. You 和 your provider should weigh this risk against the benefits of getting a correct diagnosis for a medical problem.

Tell your provider before having this test if you are pregnant or breastfeeding. Infants 和 babies developing in the womb are more sensitive to radiation because their organs are still growing.

Rarely, people may have an allergic reaction to the tracer material. Some people have pain, redness, or swelling at the injection site.

注意事项

It is possible to have false results on a PET扫描. 血糖 or insulin levels may affect the test results in people with diabetes.

Most PET扫描s are now performed along with a CT scan. 这种组合扫描称为PET/CT. 这有助于找到肿瘤的确切位置.

参考文献

杜姆斯C. 正电子发射断层扫描. 见:broadus VC, Ernst JD, King TE等编. 穆雷 & 纳德尔呼吸医学教科书. 7日艾德. Philadelphia, PA: Elsevier; 2022:chap 25.

Glaudemans AWJM, Israel O, Slart RHJA, Ben-Haim S, Slart RHJA. 血管PET/CT和SPECT/CT. 见:Sidawy AN, Perler BA编. Rutherford's Vascular Surgery 和 Endovascular Therapy. 10日艾德. Philadelphia, PA: Elsevier; 2023:chap 31.

张建军，张建军，张建军，等. 功能和分子神经影像学. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley 和 Daroff's Neurology in Clinical Practice. 8日艾德. Philadelphia, PA: Elsevier; 2022:chap 42.

Nair A, Barnett JL, Semple TR. 胸部影像学的现状. In: Adam A, Dixon AK, Gillard JH, Schaefer-Prokop CM, eds. 格兰杰 & Allison's Diagnostic Radiology: A Textbook of Medical Imaging. 7日艾德. Philadelphia, PA: Elsevier; 2021:chap 1.