Chronic hepatitis B patients and hepatitis B virus carriers, what is the most worrying and anxious thing for them? They are worried that one day they will develop cirrhosis of the liver, especially liver cancer, and they think that having liver cancer is a death sentence, so they are afraid of talking about cancer. Therefore, those who are positive for hepatitis B surface antigen or hepatitis C antibody and meet one of the following conditions should pay high attention to the possibility of liver cancer and detect it as early as possible, so as to provide timely and effective treatment. 1.Age over 35 years old; 2.History of chronic hepatitis for more than 5 years; 3.Family members with confirmed liver cancer; 4.Long-term alcoholic; 5.Hepatitis transmitted vertically by mother; 6.Long-term consumption of pickled, smoked and moldy food; 7.Long-term work stress, excessive workload or long-term mental depression; 8.Organ transplant patients. The above-mentioned patients are high-risk groups of liver cancer. Regular and continuous follow-up examinations and observations should be conducted for these people, which is an effective method for early detection of liver cancer. Specific practices are: i. Regular AFP measurement: Start to check AFP every 3 months along with liver function. If there is elevated AFP when chronic liver disease is active, it usually starts 2~4 weeks after ALT is elevated; 2~4 weeks after ALT is decreased, AFP also starts to decrease. If ALT decreases or is normal and AFP keeps increasing, liver cancer should be highly suspected. if there is no abnormality in AFP, check it once every 3-4 months at first and then insist to check it once every 6 months. The amount of AFP in normal human serum is less than 20 micrograms/liter; when hepatocellular carcinoma occurs, the function of producing this protein is restored again, resulting in progressive increase of AFP. In China, about 60%-70% of liver cancer patients have AFP higher than normal value. If AFP ≥400ng/ml for 1 month or ≥200ng for 2 months, without evidence of active hepatitis and excluding pregnancy and germinal gland embryonal carcinoma, the diagnosis of liver cancer can be made, and the false positive rate is about 2%. However, methemoglobin is not unique to hepatocellular carcinoma. Generally, when methemoglobin is elevated, imaging examination should also be performed in conjunction. Ultrasound is an economical and non-radioactive imaging test, which is an important tool for liver cancer screening in the population, and can determine whether there are occupying lesions in the liver. When ultrasound suggests substantial intrahepatic occupancy, combined with elevated AFP, the possibility of hepatocellular carcinoma should be highly suspected. If AFP is elevated and ultrasound shows a liver mass, the accuracy of diagnosing liver cancer is over 90%. Further CT or MRI examinations should be performed to confirm or exclude the diagnosis. CT and MRI scan: CT is one of the most sensitive methods to detect liver cancer, and with appropriate enhancement method, the detection rate of lesions can be over 90%. Sometimes CT is still difficult to diagnose small hepatocellular carcinoma, isodense hepatocellular carcinoma and atypical hepatocellular carcinoma, so it should be combined with other examinations to make a comprehensive analysis. Magnetic resonance imaging (MRI) is a very useful method for localization of liver cancer, and MRI has the following advantages compared with CT examination: ① it can image in multiple planes (i.e., three kinds of images in cross-sectional, coronal and sagittal planes), and its resolution of soft tissues is better than CT; ② there is no radioactive damage, and no conventional contrast agent is needed, so that adverse reactions can be avoided; ③ the sensitivity of detection is high, and it is better than CT for the differentiation of benign and malignant liver tumors, especially for the differentiation of hemangioma. The disadvantages of MRI examination are high examination cost, long imaging time, and breathing motion can interfere with liver imaging and cause blurred images. Therefore, it is not yet used as a routine examination for liver cancer.