  This article examines the critical role of fast Monte Carlo dose calculations
in advancing proton therapy techniques, particularly in the context of
increasing treatment customization and precision. As adaptive radiotherapy and
other patient-specific approaches evolve, the need for accurate and precise
dose calculations, essential for techniques like proton-based stereotactic
radiosurgery, becomes more prominent. These calculations, however, are
time-intensive, with the treatment planning/optimization process constrained by
the achievable speed of dose computations. Thus, enhancing the speed of Monte
Carlo methods is vital, as it not only facilitates the implementation of novel
treatment modalities but also improves the optimality of treatment plans.
Today, the state-of-the-art in Monte Carlo dose calculation speeds is 106 - 107
protons per second. This review highlights the latest advancements in fast
Monte Carlo dose calculations that have led to such speeds, including emerging
artificial intelligence-based techniques, and discusses their application in
both current and emerging proton therapy strategies.
