Figure 5. Quantitative PET for detection of CAR T cells and luminescence of tumor burden in survivors vs. nonsurvivors.

Representative longitudinal, PET/CT (coronal view of 20-mm-thick plane, maximum intensity projection [MIP]) and concurrent bioluminescence imaging of survivors (n = 4) (A) vs. nonsurvivors (n = 5) (E). Diaphragms are traced with dotted lines, drawn to visualize tumor burdens separately in lungs and liver. Trend-line graphs plot region of interest (ROI) values for DOTATOC uptake (percentage injection dose per volume [%ID/cm³]) against bioluminescence values (photons [P]/sec) in the lungs taken from the same mice on the same day. Luminescence images are drawn with the same upper bound (10⁶ P/mm²/sec) with gradually increasing lower bounds (X16, X20 for 2.5 × 10⁴ P/mm²/sec and X23, X27 for 5 × 10⁴ P/mm²/sec) for clarity of delineating tumor burden. Longitudinal PET/CT images of the upper body cropped at the kidney apex are drawn with a uniform range of DOTATOC concentrations (0.5–5.0 %ID/cm³), while whole-body PET/CT images are drawn in 0.5–5.0 %ID/cm³ for (A) and 1–10 %ID/cm³ for (E). Quantification of luminescence and DOTATOC uptake by the lungs (B and F) and body weight change (C and G) is shown for survivors and nonsurvivors. Representative longitudinal, PET/CT (transverse view of 1-mm-thick plane, MIP) views of lungs are shown for survivors (D) and nonsurvivors (H). PET images are drawn in indicated ranges. X, number of days after tumor xenograft; SR, treated with SSTR2-R6.5-CAR–transduced T cells.