The bio-imaging techniques have widespread applications from diagnosing diseases to investigating the body tissues at the cells level. Traditionally, these techniques were used mainly in the orthopedic treatment. However, with the development of infrared cameras, ultrasound, and radio wave technology, they are used in different medical fields such as cardiovascular analysis, neurological treatment and infant care. This paper reviews the common bio-imaging techniques used in the brain imaging and compares them based on resolution, contrast, biological risks involved, and price.