Science and medicine have long been close partners; this is particularly true in radiology where the availability of imaging techniques is central to diagnosis. An understanding of the science underlying an imaging process enables the development of new or improved techniques, comprehension of the imaging limitations and even the creation of a research portfolio.

Knowledge of scientific principles is also mandated as a result of a need to understand best and safest practice, especially in the use of ionising radiation where legislation, guidance and risk all form part of a medical specialist's pressures at work. It is no surprise therefore that radiologists are obliged to study and pass physics exams. Such exams can present a considerable challenge and the authors of this work recognise and sympathise with that challenge and have created a volume that is intended to be an educational resource and not just a pre-exam 'crammer'. Both authors have considerable experience in teaching, supporting and examining in medical science and have developed an awareness of where those sitting professional exams have traditionally struggled. This text is a distillation of that experience and covers:

• Basic physics
• X-ray imaging
• Imaging theory
• Radiation protection
• Computed tomography
• Ultrasound Magnetic resonance
• Nuclear medicine

The text itself is arranged in a manner to encourage learning and an understanding of the key concepts rather than just provide a vehicle to pass the exams. The images and diagrams that accompany each question should provide a stimulus to the concepts being challenged, while the answers also contain explanations, which in many instances goes beyond that strictly necessary to support the answer.