Accumulation of [18F]-TBD in cisplatin-treated OVCAR-5 cells. (a) OVCAR-5 cells were pretreated for 48 h with 8 μM cisplatin, 8 μM cisplatin and 20 μM Z-VAD-FMK, or PBS. Then, cells were treated with 0.44, 2.5, or 25 μCi of [18F]-TBD for 30 min. Normalized activity (counts per minute, CPM) was graphed (mean ± standard deviation) against the input activity and fit to a linear regression for each cell treatment. ANCOVA analysis of the slopes shows that probe uptake in cells treated with cisplatin is significantly different (p = 0.022, n = 3 for each condition) than uptake in untreated cells or cisplatin-treated cells where apoptosis is pharmacologically inhibited. (b) Retention of [18F]-TBD in OVCAR-5 cells treated with cisplatin for 48. The reported cisplatin IC50 value is indicated by a dotted line.27 Normalized counts were graphed (mean ± standard deviation) against cisplatin concentration and fit to a nonlinear regression. A statistical F-test finds that the slope is nonzero with high certainty (p < 0.001, n = 3 for each condition).