radiation response Article 7 Humans 6 human 6 radiation dose 6 Male 5 controlled study 5 male 5 procedures 5 Animals 4 Dose-Response Relationship, Radiation 4 adverse event 4 animal 4 nonhuman 4 priority journal 4 Female 3 Head and Neck Neoplasms 3 adult 3 female 3 head and neck tumor 3 radiotherapy dosage 3 Adult 2 Aged 2 Coronavirus 2 Mice 2 Middle Aged 2 Organs at Risk 2 Radiotherapy 2 Radiotherapy Dosage 2 Radiotherapy, Intensity-Modulated 2