Method and apparatus for conformal radiation therapy

A method and apparatus for conformal radiation therapy, with a radiation beam having a pre-determined, constant beam intensity, treats the entire tumor volume of a patient's tumor, and the beam intensity of the radiation beam is spatially modulated across the tumor, by separating the radiation into a plurality of treatment beam segments and independently modulating the beam intensity of the plurality of radiation beam segments. The independent modulation of the beam intensities may be accomplished by selectively and independently filling, or removing, a flowable, radiation blocking material from a compartment associated with each radiation beam segment.