Feasibility Study of Personalized Ultra-fractionated Stereotactic Ablative Radiotherapy (PULSAR) for Cancers of the Central Lung

This will be achieved by demonstrating the feasibility of applying adaptive radiation therapy given in PULSAR fractionation and using a 1.5T MR-guided linac system with real-time motion monitoring (Unity, Elekta). The hypothesis is that safety can be improved through: (1) better visualization of tumors, leading to less uncertainty when delineating GTVs; (2) reduced margins for setup, motion, or other sources of uncertainty; and (3) improved normal tissue healing between radiation fractions. To achieve this, we propose a personalized ultrafractionated stereotactic adaptive radiotherapy (PULSAR) delivery schedule, administering 5 fractions total, given as one fraction every 3 weeks (Fig. 3) and using MRI-guided adaptive treatment planning. This study is single arm in nature and in the feasibility phase