Tumor vascular networks look different from normal vascular networks, but the mechanisms underlying these differences are not known. By studying the scale-invariant behavior of normal and tumor vascular networks we show that vascular networks exhibit three classes of fractal behavior. Tumor networks display percolationlike scaling. Normal arteriovenous networks display diffusion-limited scaling, and normal capillary networks are compact structures. The mechanisms responsible for these differences are suggested using a growth model.

• Received 8 May 1995

DOI:https://doi.org/10.1103/PhysRevLett.75.2428