Global External Beam Radiation Therapy Devices Market By Type (Intensity-Modulated Radiation Therapy, Image-Guided Radiotherapy, Tomotherapy, Stereotactic Technology, 3d Conformal Radiotherapy, and Proton Beam Therapy), By Application (Prostate Cancer, Breast Cancer, Lung Cancer, Head & Neck Cancer, and Colorectal Cancer), By Region and Key Companies - Industry Segment Outlook, Market Assessment, Competition Scenario, Trends and Forecast 2019-2028