In the world of diagnostic imaging, the main goal is to achieve a clinically diagnostic image with minimal harm to the patient. This responsibility is shared between many individuals within what I call “the diagnoctic medical imaging equation”. In this equation, medical imaging technologists are responsible for operating the equipment properly and safely. They are trusted with deploying the right techniques and procedures to ensure satisfactory imaging results are achieved. Radiologists on the other hand are responsible for determining the appropriate imaging protocols needed to answer the critical clinical question. They are also responsible for evaluating the resulting images and providing a thorough and accurate report. In addition, modality and system engineers ensure equipment remain functional and up to standards. Engineers, medical imaging technologists, and radiologists are equally important in this equation; however, there has always been a missing link. How can we ensure that all sides of the equation achieve their goals. How can we scientifically determine that all parts of this equation are functioning as they should. When scientific input is required, where do we go? This is the role of the medical physicists. The medical physicist is the fundamental link that has been missing from diagnostic medical imaging for decades but has recently become an integral part radiology department and diagnostic medical imaging equation.