This paper proposes a novel hardware accelerator for wearable and portable radar-based microwave breast imaging applications. The hardware accelerator is implemented on a low-cost and compact FPGA that is much cheaper than other accelerators developed in previous studies. The proposed hardware accelerator is demonstrated by using experimental tests with different configurations. Data was obtained from a wearable antenna array system and processed through microwave imaging in space-time (MIST) algorithm. The results from the proposed hardware accelerator show an improvement in experimental execution time that is 4 times faster than those obtained from computer-based methods.