Ultrasonography in Image-Guided Radiotherapy: Current Status and Future Challenges

Ultrasound is a radiation-free, portable, cost-effective imaging modality, which currently is the only real-time volumetric image guidance option clinically available for radiotherapy applications. Its advantages, among which good soft tissue contrast and high resolution, and its challenges, as for example limited field of view and operator dependence, are discussed together with the future vision and the most innovative and advanced applications