Technological advancements and outlook in proton therapy

Intensity-modulated proton therapy (IMPT) using pencil beam scanning (PBS) technology has revolutionized the practice of particle therapy in recent years. Desired dose distributions over clinical target volumes can be achieved by optimizing the weights of individual pencil beams with different energies by using an inverse planning process. Two general approaches have been used to optimize a scanning beam plan. The first, multifield optimization (MFO), simultaneously optimizes all spots from all fields. The second approach is single-field optimization (SFO), in which each field is optimized individually to deliver a fraction of the prescribed dose to the entire target volume(s). IMPT is the most advanced radiation therapy modality available to date to date. Despite its superior dosimetric advantages, various challenges limit the realization of the full potential of IMPT from realizing its full potential. Various technologies have been advanced and will continue to be advanced to meet these challenges.