Objective. Proton minibeam radiotherapy (pMBRT) is a novel approach to widen the therapeutic window by balancing tumor control and reducing toxicity to healthy tissues. Among the various ways to generate minibeams, a multislit collimator (MSC) is a convenient approach for integration into existing beamlines. Here, we focus on optimizing the MSC to achieve uniform doses in the planning target volume (PTV), enabling direct comparisons with conventional proton therapy and highlighting pMBRT’s ...| iopscience.iop.org