The full name of PET is positron emission computer tomography, which is currently the most advanced molecular imaging diagnostic equipment in the world. It has the value of early detection and early diagnosis of malignant tumors, which can make the discovery time of most tumors more than one year earlier and win precious treatment time for patients.
Mr. Li recently underwent a physical examination at the PET center, and the examination revealed that his rectum had lesions with active growth and metabolism. Doctors at the PET center believe that there is a malignant lesion here, but Mr. Li doesn't feel any discomfort, but occasionally there is a small amount of blood in the stool, which has always been thought to be caused by hemorrhoids. Subsequently, on the advice of the doctor, Mr. Li underwent a pathological biopsy, which was confirmed to be rectal cancer. Due to the early diagnosis and treatment, Mr. Li has a very good prognosis.
During the PET examination, the doctor first injects a positron nuclide-labeled glucose analogue into the patient's body through a vein, and then uses PET to detect its distribution throughout the body. Due to the active growth and metabolism of tumor tissue and the high demand for sugar, there will be high FDG aggregation at the tumor focus, which appears as a "bright spot" on the PET image. Except for the bright spots caused by some physiologically high metabolic tissues or urinary system excretion on the image, these bright spots are tumor lesions.
PET has a wide range of clinical applications. In addition to early diagnosis of tumors, it can also solve the following problems:
1. A mass is found on CT. Is it a tumor? Is it benign or malignant?
2. In addition to the primary tumor, do patients with malignant tumors have other metastases?
3. Metastasis or tumor markers are found to be significantly elevated, where is the primary tumor?
4. After the tumor is treated, is the treatment effective? Is there a recurrence? Does the treatment plan need to be changed?
In addition, PET can also be used for early diagnosis of myocardial ischemia, early diagnosis of Alzheimer's and Parkinson's disease, etc.
When undergoing a PET examination, the examinee (including patients or health examiners) has no other pain except for intravenous injection. Although the positron drugs used in PET examinations have a certain amount of radioactivity, they are used in small amounts and have a short half-life. The radiation dose of positioning CT during the PET inspection is also within the safety range prescribed by the state, so the PET inspection is safe.
Due to the huge cost of the entire set of equipment and high maintenance and operation costs for PET inspection, the cost of a PET/CT inspection is relatively high. Although PET is a good physical examination method, a full-body examination costs 7000~8000 yuan. Therefore, we do not recommend excessive use of PET for health checkups.
For healthy people, under good economic conditions, we recommend a PET examination every two years or so.
For those who find high levels of tumor markers (CEA, AFP, CA125, CA199, CA50, etc.) during physical examination, but no tumor is found in routine examination, PET examination can be done to confirm whether there is a malignant tumor in the body.
For patients with malignant tumors, PET examinations can be done every six months or a year after surgery or chemotherapy to determine whether there is recurrence or metastasis.