A patient, 38 years old, came to our hospital for PET/CT examination for a definite diagnosis of “left lung mass”, as he felt a “mass at the glabellar process” in the past two months, which tended to increase in size. He came to our hospital for PET/CT examination for a definite diagnosis. The CT image revealed that the patient’s saber prominence was anteriorly elevated against the muscle and resembled a mass (see figure), and no other abnormal structures or metabolic foci were seen near the saber prominence. However, it seemed that the patient had a sixth feeling that he would get a tumor. Although PET/CT excluded the abnormal mass of the saber process, it unexpectedly found a tumor in the nasopharynx, and PET/CT showed that the patient had a thickened posterior nasopharyngeal apex and right wall with active metabolism, and several enlarged lymph nodes in the right posterior pharynx and right cervical area II with active metabolism, and no abnormal metabolic foci were found in other locations of the body, which was considered as nasopharyngeal cancer with local lymph node metastasis ( It was considered to be nasopharyngeal carcinoma with local lymph node metastasis (see figure). At present, the patient is in good general condition after timely and regular treatment. In this case, although there is no mass in the glabella, why does the patient feel abnormal, and is it related to nasopharyngeal cancer? In this case, the mass invaded the rupture hole, and even if it invaded the brain nerve, the clinical symptoms were not consistent. It is speculated that the “saber mass” may be a psychological effect of the patient, because the patient was highly stressed and afraid of cancer due to the previous “lung tumor history”, and therefore mistook the normal and slightly convex structure for a mass. At that time, if a CT examination of the chest was performed alone, this nasopharyngeal cancer could not be detected at an early stage. It is evident that PET/CT can solve the problems of the patient while detecting the more serious “bombs” lurking in the body. Although MRI is the first choice for T and N staging of nasopharyngeal cancer, PET/CT also has its unique advantages in its N and M staging. Because of the high SUV value and high metabolism of nasopharyngeal carcinoma, PET/CT imaging can detect the lesion earlier, which can achieve early detection and early diagnosis. Many reports in the literature suggest that PET/CT imaging is even better than MRI in N-staging (except posterior pharyngeal lymph nodes), and some studies show that the sensitivity and specificity of PET/CT and MRI in assessing cervical lymph nodes are 97-100%/84-92%, 73-97%/73-97%, respectively, especially in lower cervical lymph nodes, where the sensitivity, specificity, and accuracy are as high as 100%, while MRI was 84%, 98% and 90%, respectively. For M staging, PET/CT shows systemic anatomical and metabolic features and can detect more lesions than conventional imaging can. Currently, conventional imaging examinations to evaluate M staging are generally performed from the head to the level of the adrenal glands, but Iagaru Andrei reported that 7.7% of distant metastases in patients with PET/CT were below the adrenal glands, so PET/CT in M staging It has a clear advantage, especially in the detection of bone metastases without bone changes in early stages and lymph node metastases in small occult sites. In conclusion, for people with high risk of tumor, PET/CT screening can detect malignant tumor at an early stage, and PET/CT examination has good advantages in judging the benignity and malignancy of lesions, screening for recurrence, precise staging of tumor, and evaluation of therapeutic efficacy, which is of good value for clinical formulation of precise treatment plan for malignant tumor.