They engineered CD19-directed and B-cell maturation antigen-directed CAR T cells to express NIS (NIS+CART19 and NIS+BCMA-CART, respectively) and tested the sensitivity of [18F]tetrafluoroborate ([18F]TFB) to detect trafficking and expansion in systemic and localized mouse tumor models and in a CAR T-cell therapy toxicity model. The gene discussed is SLC5A5; the disease is neoplasm.