Fig. 4.

The radiobiology of the bystander effect-induction by SBRT-PATHY. (Photo Credit Dr. Slavisa Tubin). The figure summarizes the radiobiology of the bystander effect-induction by SBRT- PATHY. An 18F-FDG PET combined with a contrast-enhanced CT was used for the definition of BTV (smaller yellow contour), which corresponds to the junctional region between the central necrotic segment (black region) and the contrast- enhanced, hypermetabolic peripheral tumor (red contour, not targeted for irradiation). The red arrows represent “anti-angiogenic bystander signal” (blue pellets) released by the irradiated hypoxic tumor, inducing the regression of the non- targeted tumor. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)