To investigate the predictive value of 89Zr-DFO-CD4 and 89Zr-DFO-CD8a the TGI from day 0 to day 10 in Sym021 treated mice relative to the growth of the control group was compared to the maximum baseline tumor-to-heart ratio of 89Zr-DFO-CD4 and 89Zr-DFO-CD8a. The gene discussed is CD4; the disease is neoplasm.