In certain embodiments novel sparse orthogonal collimators (SOCs) for use in radiotherapy are provided. In certain embodiments the SOCs comprise 2 layer 4 bank orthogonal collimators with 2-8 leaves in each of the 4 banks. Instead of using the limited heuristic approach to create jaw-only IMRT, a novel fluence map optimization method is provided based on wavelet decomposition and this method is used for IMRT. An algorithm to simplify the fluence maps with minimal and predictable dose quality compromise is also provided.