Graphene is an allotrope (form) of carbon consisting of a single layer of carbon atoms arranged in an hexagonal lattice. It is the basic structural element of many other allotropes of carbon, such as graphite, charcoal, carbon nanotubes and fullerenes.
In cases where surgery and radiation are combined, proton therapy is an ideal part of brain cancer treatment. Different brain tumors require different doses of radiation for control and eradication. Like any other organ in the body, the brain can only tolerate a limited amount of radiation.
Proton therapy treats tumors closer to the surface of the body with lower energy protons. Accelerators used for proton therapy typically produce protons with energies in the range of 70 to 250 MeV (mega electron volts; million electron volts).