Cardiac sarcoma patients have been treated with definitive proton radiation therapy with respiratory-gated double-scattered proton beams at MGH. This study evaluates the potential dosimetric advantages and technical implementation of using cardiac gating to ECG and respiratory gating – a technique known as cardiac-respiratory double gating. The double gating spares organs at risk better than respiratory single gating while providing reasonable dose coverage. The results will be presented for implementation of a double gating system in double scattering and pencil beam scanning systems.