PET/MR in the Staging and Efficacy Evaluation of Newly Diagnosed NK/T-cell Lymphoma

Inclusion Criteria: * Pathologically diagnosed NK/T-cell lymphoma based on the WHO classification 2016 * Age from 14 to 70 years-old * ECOG 0-2 score * Patients with a life expectancy of at least 6 months * Patient has not been treated before for NK/T cell lymphoma * Commit to abide by the research procedures and cooperate with the implementation of the whole process of research * Written informed consent Exclusion Criteria: \- Subjects who meet any of the following criteria are not eligible for study entry * Diagnosed aggressive NK cell leukemia * Pregnant or lactating women * Liver and kidney insufficiency * Other PET/MR contraindications: 1. Those with implanted functional electronic devices such as cardiac pacemakers 2. Carotid aneurysm clipping and other implants are ferromagnetic materials 3. Implanted perfusion devices such as insulin perfusion pumps 4. Those who do not cooperate in examinations such as coma, mental illness, and critically ill patients 5. Those who are claustrophobic * Other concurrent and uncontrolled medical conditions that the investigator believes will affect the patient's participation in the study