ABSTRACT
Prompt gamma imaging has become the most promising technique for real-time in vivo range verification. Since 2006, several groups around the world conceived and developed prototypes with millimetric precision that can tackle nowadays the range uncertainties within proton therapy. In this chapter, we explore the physics behind prompt gamma generation and the methods to increase the signal-to-noise ratio. Some advancements on the nuclear models and cross-sections are also presented. A comprehensive overview of the historical development of this technique along the past 15 years is provided and the four most consolidated approaches are compared. From those, two have reached the clinical phase and will give us soon useful insights about treatment delivery and how to apply range verification in the daily routine. Many challenges still remain and synchrotron-based facilities will also need a dedicated system that verifies the range of other beam species, such as 4He, 12C, and 16O. In the next decade, we expect to have these systems installed worldwide and working as fundamental tool for most of the proton therapy centers. The knowledge of this technique will be therefore of paramount importance among the medical physics community.
