Biomedical imaging techniques had significantly improved the health care of patients. Image guided therapy has reduced the high risk of human errors with improved accuracy in disease detection and surgical procedures. The chapter provides an overview of existing imaging methods and current imaging approaches and their potential to unravel the challenges in medical field. First part of the chapter picture outs the basic concepts and mechanism of various imaging techniques that are currently in use. The second part explains about the features of image processing system and future trends in image guided therapy extended with a short discussion on radiation exposure in medical imaging. The authors trust the chapter to be beneficial to the beginners in the area of medical science and to the clinicians.