Impact of Spot Size and Spacing on the Quality of Robustly Optimized Intensity Modulated Proton Therapy Plans for Lung Cancer

Chenbin Liu, Steven E. Schild, Joe Y. Chang, Zhongxing Liao, Shawn Korte, Jiajian Shen, Xiaoning Ding, Yanle Hu, Yixiu Kang, Sameer R. Keole, Terence T. Sio, William W. Wong, Narayan Sahoo, Martin Bues, Wei Liu