Assessment of regional tumor hypoxia using 18F-fluoromisonidazole and 64Cu(II)-diacetyl-bis(N4-methylthiosemicarbazone) positron emission tomography: Comparative study featuring microPET imaging, Po2 probe measurement, autoradiography, and fluorescent microscopy in the R3327-AT and FaDu rat tumor models

摘要: Purpose: To compare two potential positron emission tomography (PET) tracers of tumor hypoxia in an animal model. Methods and Materials: The purported imaging agents 18F-fluoromisonidazole (FMISO) 64Cu(II)-diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) were compared by serial microPET Fisher-Copenhagen rats bearing the R3327-AT anaplastic rat prostate tumor. Probe measurements intratumoral P o 2 with image data. At microscopic level, relationship between spatial distributions 64Cu (assessed digital autoradiography) immunofluorescent detection pimonidazole) was examined. 18F-FMISO 64Cu-ATSM images also acquired nude xenografts derived from human squamous cell carcinoma line, FaDu. Results: In tumors, distribution remained relatively constant 1–4 h after injection. However, that displayed a significant temporal evolution for 0.5–20 injection most tumors. general, only when imaged at later times (16–20 injection) did it correspond to 18F-FMISO. Oxygen probe broadly consistent late but not early images. negative correlation found assessed positive times. For FaDu model, similar general concordance scans. Conclusion: difference behavior models suggests tumor-specific dependence Cu-ATSM uptake retention under hypoxic conditions.