SUper-Resolution Ultrasound Imaging of Erythrocytes (SURE) in Normal and Malignant Lymph Nodes

Inclusion Criteria: * Participants must be 18 years or older, at the time of signing the informed consent * Participants who can lie still for 1 minute * Capable of giving signed informed consent Inclusion criteria for healthy participants: * Participants who are overtly healthy as determined by medical history * Participants who have a superficial lymph node laterally on the neck with a normal appearance on standard B-mode ultrasound available for SURE imaging Inclusion criteria for participants with head and neck cancer or lymphoma: * Participants who, besides their untreated head and neck cancer or lymphoma, are overtly healthy as determined by medical evaluation and medical history * Participants with lymphoma or head and neck cancer and lymph node metastasis verified by a biopsy or surgical excision. * Participants who have superficial lymph nodes laterally on the neck Exclusion Criteria: * Pregnancy * Dementia * Physique making ultrasound scanning difficult * Ongoing or recent (within the last 4 weeks) infectious disease (bacterial, viral, fungal, or protozoal) which may give rise to reactive lymph nodes * Diseases that cause lymphadenopathy: Some chronic infectious diseases (HIV, Tuberculosis, Hepatitis B), Systemic diseases (rheumatoid arthritis, systemic lupus erythematosus, sarcoidosis, other rare systemic diseases\*), Primary adrenal insufficiency (Addison´s disease), Leukemia, Lymphoma or other cancers (besides the type of cancer the participant is being examined for at the Department of Otorhinolaryngology, Head and Neck Surgery \& Audiology, Rigshospitalet) * Drugs that cause lymphadenopathy: Antibiotics (Cephalosporins, Penicillin, Sulfonamides), Antiepileptics (Carbamazepine, Ethosuximide, Lamotrigine, Phenytoin, Primidone), Antihypertensives (Atenolol, Captopril, Hydralazine), Other (Allopurinol, Imatinib) * Castleman's disease, Kikuchi's disease, Kawasaki disease, Inflammatory pseudotumor, Amyloidosis, Kimura disease, Rosai-Dorfman disease, IgG4-related disease, Still's disease, dermatomyositis, Churg-Strauss, histiocytosis, chronic granulomatous diseases, Autoimmune lymphoproliferative syndrome, lipid storage diseases.