A commercial ultrasound scanner, a customized co-linear array ultrasound transducer and a real-time temperature feedback controller have been combined to generate controlled mild hyperthermia. Previous studies have shown that single beam-based image-guided local drug delivery can improve the treatment of small tumors. In this study, a scanned-beam based insonation mode was developed to achieve uniform therapy over a larger region. A color-region of interest (ROI) was used to define the scanned area, while periodic B-mode imaging was used to visualize the tumor. In this study, a thermal strain algorithm was also examined for temperature estimation and this algorithm will be applied for temperature control in the future.