Table 2.

Current immune cell tracking methods for immunotherapy, including contrast agent, cell therapy and imaging modality

Imaging modality	Nanoparticle/contrast agent	Cell-based therapy	Application	Ref.
BLI	Firefly luciferin	NK cell therapy	Tracking immune cell migration, gene expression, and tumor growth	64 and 65
FLI	Fluorescent quantum dots (QD705)	NK cell therapy	Imaging immune cell distribution and activity, monitoring therapeutic efficacy	64 and 66
FLI	1,1-Dioctadecyltetramethyl indotricarbocyanine iodide (DiR)	Adoptive immune cell therapy with T-lymphocytes	Image and assess tumor targeting and retention of directly labeled T-lymphocytes	67
IVI	tdTomato fluorescent protein	CAR-T cell therapy	Monitor in vivo antitumor reaction of CAR-T cells on PCNSL	68
CT	Bi2S3 Nanoparticles modified with ovalbumin	Dendritic cell-based cancer vaccine	Monitor DC migration to lymph nodes and induce anti-ovalbumin immune activity	69
CT	20 nm GNPs	TCR Therapy	Tracking T-cells accumulation at tumor site to determine efficacy of TCR therapy for melanoma	70
CT	20 nm GNPs	NK cell therapy	Longitudinally tracking NK cell accumulation at the tumor site	71
CT	Dendrimer entrapped GNPs	Macrophage therapy	Macrophage polarization and tracking in vivo	51
CT	GNPs modified with 11-mercaptoundecanoic acid	Monocyte therapy	Tracking monocyte accumulation in atherosclerotic plaques	72
CT	80 nm GNPs	Mesenchymal stem cell therapy	Tracking mesenchymal stem cell migration in the subretinal layer	73
PET/SPECT	111Indium (In)-tropolone	CAR-T cell therapy	Monitor T cell trafficking in vivo. Engineering cells using radiotracers.	74
PET/SPECT	[18F]F-AraG	Stem cell therapy	Track alloreactive T cells, indicate acute GVHD.	22
PET/SPECT	89Zr-oxine	CAR-T cell therapy	Track CAR-T cells for up to 6 days post transfer, compare administration techniques.	75
PET/SPECT	[18F]fluoropropyl-trimethoprim	CAR-T cell therapy	Tumor monitoring and homing	76
MRI + FLI	PLGA nanoparticle containing SPIO + ICG + ovalbumin	Dendritic cell-based cancer vaccine	DC activation and monitoring migration via FLI and MRI	77
MRI	19F PFPE	Dendritic cell therapy	In vivo tracking of dendritic cell migration	78
MRI	19F PFPE	Adoptive NK cell therapy	Longitudinal tracking of NK cells following intratumoral injection	79
MRI	19F PFC	Splenocyte and T cell therapy	Whole body monitoring of splenocytes and T-cell behavior and migration	80
PA	NIR-797-isothicyanate	T cell therapy	Monitoring T cell migration to tumor site
PA	Semiconducting polymer nanoparticle	Macrophage therapy, neutrophil therapy and MSC therapy	Monitoring macrophage, neutrophil and MSC migration to inflammation site	81
PA	Gold nanorods	Dendritic cell therapy	DC activation and longitudinal tracking of migration to lymph nodes	82
PA + FLI	Gold nanorods coated in fluorescent dye doped silica	Macrophage therapy	In vitro bimodal imaging of macrophages	83
US/PA	Silica coated gold nanorods	T cell therapy	In vivo tracking of T cells in a solid tumor and monitoring oxygen saturation	84
PA	Silica coated gold nanorods	Cytokine induced killer cell therapy	Imaging of CIK cells, enhanced antitumor activity and photothermal therapy for gastric cancer	85
PA	Gold nanoprisms	Cytokine induced killer cell therapy	Imaging of CIK cells, enhanced antitumor activity and photothermal therapy for gastric cancer	86