Medical applications of time reversal (TR) such as eradication of cancerous cells, magnetic resonance imaging (MRI) for breast cancer detection, and real time tracking of renal stones will be presented. A time reversal device has the ability of recording a signal; time reversing the recorded signal; and retransmitting the signal in the reverse direction from where the original signal was received. We derive maximum likelihood (ML) detectors to locate breast tumours based on a TR setup consisting of a P- element transmitting array and an N-element receiving array. A second medical application of TR considered in the presentation is the eradication of tumour cells using radiotherapy. Though the exact location o the infected cells is known but the propagation of the ultrasound within the human body has random fluctuations due to reflection, refraction and multipath effects. In such circumstances, it is often not possible to target the infected cells accurately, resulting in undesired destruction of the neighboring healthy cells. TR techniques are derived to achieve super resolution focusing at the tumour cells in such radiotherapy applications. We derive analytical results that provide insight into the phenomena of super resolution focusing associated with time reversal. Experimental simulations illustrate the superiority of our TR tumour detection and radiotherapy eradication techniques over the current approaches practiced by medical physicians.