PET-CT is a new diagnostic technology introduced at the beginning of the 21st century, and it has been widely popularized in just a few decades mainly because PET-CT examinations have incomparable advantages of CT, MRI and other common examination equipment. To sum up, PET-CT examination has eight advantages: First, the most powerful cancer prevention equipment in the 21st century The organic combination of PET, which detects lesions, and CT, which detects anatomical structures, complement each other’s advantages, and compared with ordinary CT, MRI and other imaging examinations, PET-CT can detect abnormal lesions in the body six months in advance, with the benefit of 1+1>2. PET-CT can examine the whole body at one time and obtain the information of the whole body at one time, including cross-sectional, sagittal and coronal images of the whole body, which can visually see the parts and conditions of disease involvement in the whole body, saving a lot of time and money that other imaging needs to examine each part of the body. High sensitivity to various types of tumors PET-CT can accurately detect the lesion site in the early stage of tumors that have not yet shown abnormal morphological structure but the cell molecules have changed, and can obtain three-dimensional images to achieve early diagnosis, which is incomparable to other imaging examinations. IV. Super specificity for some tumors When MRI and CT examinations find tumors in organs, it is difficult to determine whether they are benign or malignant, especially in the early stage of lesions, while PET-CT examination can make a clear diagnosis based on the characteristics of high metabolism of malignant tumors. V. Up to 95% accuracy rate According to the characteristics of high metabolism of malignant tumor, PET-CT examination requires injection of fluorine-labeled glucose into the human body before the examination, which can cause abnormal concentration in the lesion area and thus determine the lesion site. This method can effectively detect most tumors with an accuracy rate of over 95%. PET-CT examination is actually a kind of imaging scan, just like sunlight irradiation, without any pain and trauma, and the examinee only needs to receive intravenous injection of trace tracer and lie down to rest, without any other discomfort. PET-CT examination has low radiation, safe and reliable, but the amount of nuclide used is very small, far less than the conventional CT examination of one area, and the half-life is very short, and the time of staying in the body of the examinee is very short, so the whole examination process is safe and reliable. VIII. Evaluation of the efficacy of tumor treatment After certain treatments such as surgery, radiotherapy and chemotherapy, whether the tumor has changed, whether the activity of cancer cells has decreased, and whether there is still spread in other parts of the body can be detected at a glance by PET-CT images, which effectively improves the local control rate and avoids unnecessary surgery and injuries.