Compartmental kinetic modeling of dynamic 18FMISO PET data in clinical NSCLC

1290 Objectives To conduct compartmental kinetic analysis (CA) of 18FMISO dynamic PET (dPET) in stage III-IV non-small cell lung cancer (NSCLC) patientts. Methods 15 patients diagnosed with NSCLC underwent 2 PET/CT scans (1-2 days apart) before radiation therapy (RT):a 3-min static 18FDG (S1) and 18FMISO dPET (S2).All patients were scanned in the RT position. Data acquisition for S2 was initiated at time of injection (~10mCi FMISO) and the acquired data were binned as follows: 12x10 sec, 10x1min, and 5x5min (37min).Static images (10 min) were acquired at 90±10 and at 150±10min. For both, a free-breathing time-averaged CT was acquired and used for attenuation correction and S1-S2 co-registration. The target volume was segmented on the registered S1 usimg a 50% threshhold. Average time-activity curves (TAC) were extracted from the corresponding FMISO VOI (VOIavg).Each VOIavg was further segmented using k-means into 4 clusters (C1-C4).Finally, a copy of VOIavg was placed on the contralateral healthy lung (VOIN).Plasma Input functions (IF) were deduced from the hottest 20 voxels in the aorta.CA was performed for VOIavg,C1-C4 and VOIN using PMOD with a 2-tissue, 3-compartment irreversible model (k4=0) and kinetic parameters (KP) (vB (blood volume),K1,K1/k2,k3) estimated for all patient TACs Results All patients exhibited FMISO uptake in the target volumes. The mean KPs values and their range (in min-1 for all but vB which is unitless) for VOIavg TACs for the 15 patient are: vB = 0.080 (0.018-0.15), K1 = 0.19 (0.092-0.33), K1/k2) = 0.66 (0.39-0.82), and k3 = 0.009 (0.002-0.022). For the highest-k3 cluster, the relevant KP values are: vB = 0.076 (0.0070-0.20), K1 = 0.14 (0.028-0.29), K1/k2 = 0.72 (0.45-0.96), and k3 = 0.0078 (0.0014-0.024). For VOIN k3 was an average of 38% higher in the tumor vs normal tissue. Conclusions The lesions in all patients exhibited relatively high perfusion as indicated by the K1. Nevertheless, for all patients, tumors exhibited some degree of hypoxia as indicated by 38% higher value of k3 in tumor vs normal targets. Research Support This work was partially supported by NIH grant 1U01CA157442-01A1