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

Figure 4

A pH microelectrode for measuring in vivo tumor pH. (a) A photo of an angled glass electrode with a platinum wire and 0.1 N hydrochloric acid electrolyte. (b) The microelectrode was inserted into a melanoma nodule of a patient, stabilized with sponge rubber between the skin and electrode shaft, and secured with adhesive tape. A calomel reference electrode was secured to the skin. Adapted from [16] with permission.

(a)

(b)