Puncture biopsy is an important clinical technique to obtain diseased tissue for pathological diagnosis, where imaging guidance is critical. In this paper, we describe a metal reflector-enhanced microwave-induced thermoacoustic imaging (TAI) approach capable of guiding puncture biopsy for detection of breast cancer and joint diseases. Numerical experimentations simulating puncture guidance in breast cancer and knee gout models were first conducted using (CST STUDIO SUITE) (CST) software, and then ex-vivo experiments were performed followed by qualitative observations and semi-quantitative analysis. The results of both the simulations and ex-vivo experiments showed that our reflector-enhanced TAI could image the puncture needle in high resolution with a large depth of >12cm.