RT Journal Article SR Electronic T1 4′-[Methyl-11C]-Thiothymidine PET/CT for Proliferation Imaging in Non–Small Cell Lung Cancer JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 199 OP 206 DO 10.2967/jnumed.111.095539 VO 53 IS 2 A1 Ryogo Minamimoto A1 Jun Toyohara A1 Ayako Seike A1 Hideyuki Ito A1 Hisako Endo A1 Miyako Morooka A1 Kazuhiko Nakajima A1 Takuya Mitsumoto A1 Kimiteru Ito A1 Momoko Okasaki A1 Kiichi Ishiwata A1 Kazuo Kubota YR 2012 UL http://jnm.snmjournals.org/content/53/2/199.abstract AB A new tracer, 4′-[methyl-11C]-thiothymidine (11C-4DST), has been developed as an in vivo cell proliferation marker based on the DNA incorporation method. This study evaluated the potential of 11C-4DST PET/CT for imaging proliferation in non–small cell lung cancer (NSCLC), compared with 18F-FDG PET/CT. Methods: Eighteen patients with lung lesions were examined by PET/CT using 11C-4DST and 18F-FDG. We constructed decay-corrected time–activity curves of 9 major regions as the mean standardized uptake value. We then compared the maximum standardized uptake value (SUVmax) of lung tumors on both 11C-4DST and 18F-FDG PET/CT with the Ki-67 index of cellular proliferation and with CD31-positive vessels as a marker of angiogenesis in surgical pathology. Results: NSCLC was pathologically confirmed in 19 lesions of 18 patients. Physiologic accumulation of 11C-4DST was high in liver, kidney, and bone marrow and low in aorta, brain, lung, and myocardium. Biodistribution of 11C-4DST was almost stable by 20 min after injection of 11C-4DST. Mean 11C-4DST SUVmax for lung cancer was 2.9 ± 1.0 (range, 1.5–4.7), significantly different from mean 18F-FDG SUVmax, which was 6.2 ± 4.5 (range, 0.9–17.3; P < 0.001). The correlation coefficient between SUVmax and Ki-67 index was higher with 11C-4DST (r = 0.82) than with 18F-FDG (r = 0.71). The correlation coefficient between SUVmax and CD31 was low with both 11C-4DST (r = 0.21) and 18F-FDG (r = 0.21), showing no significant difference between the tracers. Conclusion: A higher correlation with proliferation of lung tumors was seen for 11C-4DST than for 18F-FDG. 11C-4DST PET/CT may allow noninvasive imaging of DNA synthesis in NSCLC.