Radiation imaging method

A method of operating a radiation imaging system comprising an electrical insulation layer having a top surface and a bottom surface, a top electrode on the top surface of the electrical insulation layer, an array of pixel units electrically coupled to the electrical insulation layer, the plurality of pixel units including a plurality of storage capacitors, and an array of transistors connected to the array of pixel units, the method comprising:

• (1) applying a bias voltage with a magnitude no greater than a breakdown voltage of the electrical insulation layer to the top electrode;
• (2) applying a gate line bias voltage to gates of the transistors to render each of the transistors to be in an off state;
• (3) receiving ionization radiation, wherein the ionization radiation penetrates the electrical insulation layer and generate charge signal;
• (4) storing the charge signal in a storage capacitor among the plurality of storage capacitors;
• (5) changing a polarity of the gate line bias voltage of one row of the array of transistors to render all transistors in the one row to be in an on state;
• (6) integrating charges from a plurality of the storage capacitors connected along an orthogonal data line, digitizing the integrated charges as a value, and storing the value to a computer memory;
• (7) restoring the polarity of the gate line bias voltage to render the one row of the transistors to be in the off state;
• (8) changing the polarity of the next row of the gate line bias voltage to render the transistors in the next row to be in the on state;
• (9) repeating the steps of (6), (7), and (8) until all the charge signals stored in the array are read out and stored in the computer memory.