CD4 and neoplasm: The maximum 89Zr-DFO-CD4 (p=0.0002) and 89Zr-DFO-CD8a (p=0.0354) tumor-to-heart ratio were found to correlate with the relative TGI at day 10 post therapy initiation, although the correlation appeared stronger for 89Zr-DFO-CD4.