Starting from the imaging principle of PET-CT, PET-CT combines PET and CT, introduces radionuclides for imaging, and then uses CT anatomy for joint diagnosis. During the examination, certain substances are first put in, usually glucose, protein, nucleic acid, fatty acids, and short-lived radionuclides, such as F18, carbon 11, etc. Currently, the main substance used in various hospitals is fluorodeoxyglucose, or FDG for short. Different tissues of the human body have different metabolic states. In malignant tumor tissues with high metabolism, glucose metabolism is strong and there is a lot of accumulation. These characteristics can be reflected through images to diagnose and analyze lesions. In other words, PET-CT is a metabolic image, which allows PET-CT to detect lesions that cannot be found with ordinary CT earlier.
In the clinical diagnosis and follow-up observation of tumors, lymphoma patients often undergo PET-CT examinations. Why do doctors recommend that lymphoma patients undergo PET-CT instead of ordinary CT? This is determined by the particularity of lymphoma. Unlike other tumors, which have specific growth sites, lymphoma is a systemic disease. Lymphoma may grow in places where lymphoid tissue is located. In addition, lymphoma may also grow in the liver, spleen, lungs, bone marrow and other parts of the body. Many patients can only find cervical lymph node enlargement at first, and systemic examination will reveal enlarged mediastinal lymph nodes and retroperitoneal lymph nodes. PET-CT can perform whole-body imaging examination in one scan. It is very convenient and fast to examine lymphoma patients. It can obtain information more accurately, which is very helpful for the diagnosis, segmentation and treatment plan of lymphoma.
PET-CT of the whole body is significantly better than traditional CT scan in the pre-treatment and post-treatment residual lesions of lymphoma. It can detect dangerous lesions that may not be found by traditional CT. The benignity of the lesions can be preliminarily judged through metabolic activity. Vicious. In particular, it is of great significance for the evaluation of therapeutic efficacy. Accurate diagnosis and segmentation of lymphoma are critical to selecting appropriate treatments. 18F-FDG (contrast agent) PET-CT imaging is based on the characteristics of malignant tumors that increase glucose metabolism, and has important reference value for the diagnosis of lymphoma. Segmentation of lymphoma is an evaluation of the condition before treatment, and subdivision is a further evaluation of the efficacy after treatment. Accurate identification of residual mass and recurrence after tumor treatment is of great significance for formulating treatment plans.
Research shows that the sensitivity and specificity of PET examination for lymphoma patients with residual masses after chemotherapy are 50% and 69% respectively. Women with PET examination tumors do not need to undergo chemotherapy, and unnecessary treatment can be avoided. treat. For Hodgkin lymphoma that still has residual tumors after first-line treatment, PET-CT is an effective method to evaluate whether tumor cells remain in the residual tumors. The National Comprehensive Cancer Network (NCCN) guidelines recommend that patients with Hodgkin lymphoma undergo PET-CT after completion of all treatments to assess for residual disease and to biopsy benign lesions.