Method for estimation of apoptotic cell fraction of cytotherapy using in vivo fluorine-19 magnetic resonance: pilot study in a patient with head and neck carcinoma receiving tumor-infiltrating lymphocytes labeled with perfluorocarbon nanoemulsion ====================================================================================================================================================================================================================================================== * Eric T Ahrens * Brooke M Helfer * Charles F O’Hanlon * Deanne R Lister * Julie L Bykowski * Karen Messer * Benjamin I Leach * Jiawen Chen * Hongyan Xu * Gregory A Daniels * Ezra E W Cohen