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Erschienen in:
10.08.2019 | Original Article
4′-[methyl-11C]-thiothymidine as a proliferation imaging tracer for detection of colorectal cancer: comparison with 18F-FDG
Erschienen in: Annals of Nuclear Medicine | Ausgabe 11/2019
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Objective
The novel radiotracer, 4′-[methyl-11C]-thiothymidine (11C-4DST), was developed based on the DNA incorporation method as a cell proliferation marker. This study investigated the feasibility of 11C-4DST positron emission tomography/computed tomography (PET/CT) for detection of colorectal cancer, as compared with 2-deoxy-2-18F-fluoro-d-glucose (18F-FDG) PET/CT, and to correlate the two radiotracers with proliferative activity.
Methods
A total of 18 patients with newly diagnosed colorectal cancer underwent both 11C-4DST and 18F-FDG PET/CT. Tumor lesions were identified as areas of focally increased uptake, exceeding that of adjacent normal tissue. For semiquantitative analysis, the maximal standardized uptake value (SUVmax) was calculated. Proliferative activity as quantified by the Ki-67 index was estimated in tumor specimens.
Results
In all 18 patients, colorectal cancers were detected by both 11C-4DST and 18F-FDG PET/CT. The median (± SD) SUVmax for 11C-4DST (6.02 ± 2.55) was significantly lower than that for 18F-FDG (13.91 ± 7.62) (P < 0.001). 11C-4DST SUVmax and 18F-FDG SUVmax showed a significant correlation (r = 0.69, P = 0.002). 11C-4DST SUVmax and Ki-67 index were weakly correlated (r = 0.50, P = 0.04). 18F-FDG SUVmax and Ki-67 index were not significantly correlated (r = 0.44, P = 0.06).
Conclusions
Despite a significantly lower uptake of 11C-4DST than that of 18F-FDG, detection of colorectal cancer was also feasible with 11C-4DST PET/CT. 11C-4DST PET/CT might have a role in the noninvasive assessment of proliferation in colorectal cancer.