Global Proton Therapy Market By Type (Electron Beam, Proton Beam, Neutron Beam, Carbon Ion Beam, Alpha Particle Beam, and Beta Particle Beam), By Application (Pediatric Cancer, Bone and Soft Tissue Cancer, Prostate Cancer, Lung Cancer, Liver Cancer, Eye Cancer), By Region, and Key Companies - Industry Segment Outlook, Market Assessment, Competition Scenario, Trends and Forecast 2019-2028