A preliminary investigation of Cu-62-ATSM tumor hypoxia PET/CT imaging comparing with FDG PET/CT for pancreas cancer

Purpose Cu-62labeled diacetyl-bis (N(4)-methylthiosemicarbaone) (Cu-62-ATSM) is a well-knownhypoxic imaging PET tracer. The purpose of this study was to delineate thedifferences in intratumoral uptake and tracer distribution of Cu-62-ATSM andF-18 FDG in patients with pancreas cancer. The comparison of two tracers wasdone before and after carbon ion radiotherapy, and the relationship of traceruptake and patients prognosis was also investigated. Mehod Two male and twofemale (mean age, 62.5 y, range 52-69 y) with pancreas cancer underwent bothCu-62-ATSM and FDG PET/CT before the initiation of carbon ion radiotherapy(CIRT), and the set of PET/CT studies was done one month after termination ofCIRT. Two whole-body PET/CT scanners, Biograph-16 (Siemens) and Aquiduo(Toshiba) were used for data acquisition. Cu-62-ATSM and FDG were administratedapproximately 740 MBq and 370 MBq, respectively. Tumor uptake of each tracerwas analyzed semi-quantitatively by tumor to normal tissue ratio (TNR) forCu-62-ATSM and by standardized absorption value (SUV) for FDG. Result Cu-62-ATSMuptake didnt correlate with FDG uptake before CIRT, but it inverselycorrelated with FDG after CIRT because FDG uptake tended to decrease in allcases. Correlation coefficient of tumor uptake between Cu-62-ATSM and FDGbefore and after CIRT was 0.022 and -0.965, respectively. Average Cu-62-ATSMand FDG uptake before CIRT were 2.9 TNR (range 1.4-3.6 TNR) and 6.7 SUV (range2.9-10.6 SUV), and decreased to 2.7 TNR (range 1.2-4.7 TNR) and 3.8 SUV (range2.6-4.6) after CIRT, respectively. In three out of four patients before CIRTshowed high Cu-62-ATSM uptake that might reflect the trend of them beinghypoxic. A patient showed increase of Cu-62-ATSM uptake after CIRT, but FDGuptake of the same patient didnt increase and almost stable after CIRT. It mightindicate that change of Cu-62-ATSM uptake didnt necessarily correspond tochange of FDG uptake after radiotherapy. Only one patient died after CIRT, andhis Cu-62-ATSM and FDG uptake before therapy were not the highest uptake withinall patients, but both of them were relatively high. Conclusion Cu-62-ATSM andFDG didnt correlate each other before CIRT in pancreas cancer. The change ofCu-62-ATSM uptake didnt necessarily correspond to change of FDG uptake afterCIRT. Cu-62-ATSM and FDG uptake of a patient who died after CIRT were not thehighest uptake, but were relatively high.
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