Diagnostic and therapeutic imaging in oncology

Medical imaging techniques are an important element in early detection for many cancers. They are also essential for determining the location, extension and stage of the lesion in diagnosis, for guiding treatment and therapeutic interventions, and for assessing tumour response during and after treatment. Imaging methods range from anatomically based methods (ultrasound, conventional plain X-rays, fluoroscopy, computed tomography, magnetic resonance imaging) to more functionally based methods (functional magnetic resonance imaging, magnetic resonance spectroscopy, single-photon emission computed tomography, positron emission tomography). The principles of these image acquisition methods with examples of clinical indications are described. Advances in medical imaging have also been widely applied in the field of radiation oncology, often referred to as ‘therapeutic imaging’. A wide range of imaging techniques is employed at almost every step of the radiation treatment process: from diagnosis, treatment planning, dose calculations and simulation of treatment, through to irradiation on the linear accelerator. The most notable recent technical developments have led to more accurate treatment plan calculations and more precise administration of radiation to target tissue.