Monolithic silicon pixel detectors, systems and methods for the detection and imaging of radiation in the form of charged particles or X-ray photons comprise a Si wafer with a CMOS processed readout communicating via implants for charge collection with an absorber forming a monolithic unit with the Si wafer to collect and process the electrical signals generated by radiation incident on the absorber. In particular, a monolithic CMOS integrated pixel detector includes several components. Such components include a p-doped silicon wafer with a resistivity of at least 1 kΩcm (220, 310, 310′) having a front-side (224, 314, 314) comprising a CMOS processed readout electronics (250, 350) comprising pixel electronics (258, 358) and a backside (228, 318) opposite the front side. In addition, the pixel detector includes charge collectors (252, 352) communicating with the pixel electronics (258, 358) and defining the pixel size. Still further, high voltage contacts (282, 382) are provided. The region of silicon wafer (220, 310, 310′) below the charge collectors (252, 352) forms the absorber layer (226, 316) of pixel detector (240, 340). When the pixel detector (240, 340) is in operation, the charge collectors (252, 352) are disposed to receive electrical charges drifting across the absorber layer (226, 316) when generated by charged particles or X-ray photons (270, 370) incident on the absorber layer (226, 316). The readout electronics is disposed to convert said electrical charges into digital signals which can be stored, processed and displayed as images on a computer screen.