BackgroundThe accuracy of Convolution/Superposition (CS) algorithm is considered to be next to Monte Carlo algorithm (MC) for radiotherapy dose calculation algorithm. Although the calculating speed of this algorithm is much faster than that of MC, its calculating speed can not fully meet the clinical requirements. With the aid of a single graphics processing unit GPU (Tesla C1060), the CS algorithm can be accelerated to 60 times faster than the traditional CPU serial calculation. The calculating time for single field is about 1 min which can be used in some simple three dimensional conformal radiotherapy planning (3DCRT), but this calculating speed does not satisfy the speed need for intensity modulated radiation therapy (IMRT) planning.PurposeThis study aims to explore a faster calculating speed solution of CS algorithm applied to IMRT with multi GPU.MethodsThe acceleration scheme of CPU + multi GPU heterogeneous model was analyzed by using different number of GPUs. High-end GPU, i.e., Tesla C2015, was used