1. A compact microbeam radiotherapy system comprising: a distributed x-ray source array comprising a plurality of carbon-nanotube field emission x-ray sources, the x-ray sources positioned to surround an object to be irradiated and produce x-ray radiation that directs towards a common treatment volume; a collimation system positioned between each x-ray source and the object to be irradiated, wherein the collimation system collimates the x-ray radiation into either one planar beam or a plurality of parallel planar beams, each planar beam having a width of less than about 1 milimeter and wherein separation between adjacent planar beams is less than several millimeters; a precision positioning device for aligning the target with the plurality of x-ray planar beams; and a control system in communication with each of the plurality of x-ray sources for simultaneous generation of a plurality of x-ray planar beams from the plurality of x-ray sources with pre-determined x-ray dose and dose rate.