What Is Positron Emission Tomography?

Nuclear medicine molecular imaging technology mainly includes single photon emission computerized tomography (SPECT) and positron emission tomography (PET) two inspection technologies. In molecular imaging studies, the two occupy an extremely important position. This article introduces PET.

Basic Information

English name

positron emission computerized tomography

Visiting department

Department of Nuclear Medicine

Positron emission tomography routine clinical applications

PET is one of the most advanced medical imaging diagnostic equipment in the world, and it is also the most advanced medical imaging technology for human body metabolic imaging at the cell and molecular level. PET can quantitatively and dynamically detect changes in metabolites or drugs in the human body from outside the body, and it has become the best method to diagnose and guide the treatment of various malignancies, coronary heart disease and brain diseases. The application of PET in clinical medicine is mainly concentrated in the three fields of malignant tumors, nervous system and cardiovascular system. PET / CT is the combination of PET and CT, and it also has the inspection function of PET and CT. It achieves complementary advantages in the true sense. One inspection at the same time provides accurate anatomical structure and function of the lesion (such as malignant tumors) and information on metabolic changes. Improved the accuracy of disease diagnosis. PET / CT is a landmark milestone in the history of medical imaging diagnostic technology. The following describes the clinical application of PET / CT.

1. Application of PET / CT in tumor

(1) Differentiate the benign and malignant tumors: if the patient has a single nodule in the lungs, and PET / CT examination, if the nodular metabolic activity of the nodule is not high, it suggests that benign lesions are likely, and the choice of surgery should be careful. Conversely, if the metabolic activity of the nodule is increased, it may indicate malignancy, and active treatment measures should be taken, including surgery.

(2) Tumor staging: Tumor staging is an important basis for determining a patient's treatment plan. PET / CT performs whole-body imaging of patients. One imaging can provide information about whether the organs in the body such as the brain, lungs, lymph nodes, liver, adrenal glands, and bones are metastatic. Lymphoma and other tumors undergo precise clinical staging. Taking the diagnosis of lymphoma as an example, PET / CT is more accurate, because CT or MRI regards enlarged lymph nodes (> 1cm) as metastases, and many of them have enlarged lymph nodes due to chronic inflammation or have been affected by tumor tissue Invading normal-sized lymph nodes were misjudged as normal. PET is more accurate than the size based on the metabolic activity of the lymph nodes.

(3) Efficacy evaluation: Due to the high sensitivity of PET / CT and the characteristics of functional metabolic imaging, the judgment of the efficacy of radiation therapy and chemotherapy is more accurate and sensitive, which is helpful to guide clinicians to adjust the treatment plan in time.

(4) Identification of necrosis, fibrosis, and residual or recurrence after tumor treatment: PET / CT can identify tumor necrosis, fibrosis, and residual or recurrence after chemotherapy, radiation therapy, and surgical treatment, but other imaging methods are difficult to achieve.

(5) Helping to formulate a radiation therapy plan for tumors: PET / CT can help radiation therapists to outline more reasonable biological target areas and help formulate radiation therapy plans.

(6) Searching for primary tumors: Patients with known tumor metastases can further find the primary tumors by PET / CT examination.

2.Application of PET / CT in the nervous system

(1) Localization of epilepsy lesions and evaluation of surgical efficacy: The anastomosis rate of PET / CT and traumatic craniotomy EEG to locate epilepsy lesions is more than 90%, which provides a non-invasive new choice for epilepsy lesions .

(2) Early diagnosis of dementia: There is no effective treatment for dementia, but if some patients are detected early, appropriate treatment can improve symptoms or delay the progress of the disease. Therefore, early diagnosis of dementia by PET / CT is of great significance to patients, families and society, and it can also distinguish Alzheimer's disease and vascular dementia.

(3) Application in cerebrovascular diseases: early localization of transient ischemic attack and cerebral infarction, assessment of efficacy and prognosis.

3. Application in the cardiovascular system

PET / CT is the most reliable method for judging the survival of myocardium at the site of myocardial infarction. Myocardial survival in the infarct area is directly related to the acceptability of coronary artery transplantation and coronary angioplasty, and the surgical prognosis is estimated. If there is myocardial survival at the surgical site, it will be an indication for surgery and the operation will be successful.

4. Application of PET / CT in health examination

With the improvement of people's living standards and the enhancement of self-care awareness, there is more demand for health examinations. Because PET / CT is a sensitive and accurate detection method for early detection of tumor, brain, and cardiovascular diseases, some developed countries and developed areas in China have adopted PET / CT as an effective High-tech methods for screening tumor, brain, and cardiovascular diseases.