Noninvasive Evaluation of Metabolic Tumor Volume in Lewis Lung Carcinoma Tumor-Bearing C57BL/6 Mice with Micro-PET and the Radiotracers 18F-Alfatide and 18F-FDG: A Comparative Analysis.
OBJECTIVE
To explore the value of a new simple lyophilized kit for labeling PRGD2 peptide (18F-ALF-NOTA-PRGD2, denoted as 18F-alfatide) in the determination of metabolic tumor volume (MTV) with micro-PET in lewis lung carcinoma (LLC) tumor-bearing C57BL/6 mice verified by pathologic examination and compared with those using 18F-fluorodeoxyglucose (FDG) PET.


METHODS
All LLC tumor-bearing C57BL/6 mice underwent two attenuation-corrected whole-body micro-PET scans with the radiotracers 18F-alfatide and 18F-FDG within two days. 18F-alfatide metabolic tumor volume (VRGD) and 18F-FDG metabolic tumor volume (VFDG) were manually delineated slice by slice on PET images. Pathologic tumor volume (VPath) was measured in vitro after the xenografts were removed.


RESULTS
A total of 37 mice with NSCLC xenografts were enrolled and 33 of them underwent 18F-alfatide PET, and 35 of them underwent 18F-FDG PET and all underwent pathological examination. The mean ± standard deviation of VPath, VRGD, and VFDG were 0.59±0.32 cm3 (range,0.13~1.64 cm3), 0.61±0.37 cm3 (range,0.15~1.86 cm3), and 1.24±0.53 cm3 (range,0.17~2.20 cm3), respectively. VPath vs. VRGD, VPath vs. VFDG, and VRGD vs. VFDG comparisons were t = -0.145, P = 0.885, t = -6.239, P<0.001, and t = -5.661, P<0.001, respectively. No significant difference was found between VPath and VRGD. VFDG was much larger than VRGD and VPath. VRGD seemed more approximate to the pathologic gross tumor volume. Furthermore, VPath was more strongly correlated with VRGD (R = 0.964,P<0.001) than with VFDG (R = 0.584,P<0.001).


CONCLUSIONS
18F-alfatide PET provided a better estimation of gross tumor volume than 18F-FDG PET in LLC tumor-bearing C57BL/6 mice.
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China; School of Medicine and Life Sciences, University of Jinan-Shandong Academy of Medical Sciences, Jinan, China.
Yu-Chun
YC
Wei
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
Xudong
X
Hu
Department of Pathology, Shandong Cancer Hospital and Institute, Jinan, China.
Yongsheng
Y
Gao
Department of Nuclear Medicine, Shandong Cancer Hospital and Institute, Jinan, China.
Zheng
Z
Fu
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
Wei
W
Zhao
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
Qingxi
Q
Yu
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
Suzhen
S
Wang
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
Shouhui
S
Zhu
Department of Thoracic Surgery, Shandong Province Hospital, Jinan, China.
Jun
J
Li
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
Jinming
J
Yu
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
Shuanghu
S
Yuan
D000818:Animals; D018827:Carcinoma, Lewis Lung / Q000000981:diagnostic imaging / Q000473:pathology; D005462:Fluorine Radioisotopes / Q000032:analysis* / Q000493:pharmacokinetics; D019788:Fluorodeoxyglucose F18 / Q000032:analysis* / Q000493:pharmacokinetics; D005612:Freeze Drying; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010456:Peptides, Cyclic / Q000032:analysis* / Q000493:pharmacokinetics; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000032:analysis* / Q000493:pharmacokinetics; D011933:Reagent Kits, Diagnostic; D014018:Tissue Distribution; D047368:Tumor Burden
D005462:Fluorine Radioisotopes; D010456:Peptides, Cyclic; D019275:Radiopharmaceuticals; D011933:Reagent Kits, Diagnostic; C586680:alfatide II; D019788:Fluorodeoxyglucose F18