Evaluating pH in the Extracellular Tumor Microenvironment Using CEST MRI and Other Imaging Methods

Figure 5

Fluorescence imaging of tumor pHe. (a) The emission spectrum of SNARF-1 dye shows that pH is correlated with the ratio of the fluorescence signal at 570/650 nm. (b) A window chamber model can access a solid tumor growing under a coverslip in a skinfold. (c) The parametric map of pHe was determined from the ratio of fluorescence signals of SNARF-1 dye in an in vivo window chamber model of a HCT116-GFP tumor. Black and purple arrows indicate acidic environment toward which the tumor is growing. The pHe values of the tumor edge are listed near short red lines. Reproduced with permission from [19–21].

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