A flat panel detector (20) for radiation imaging includes an array of transistor switches (38) each of which is associated with a pixel electrode (36). A radiation transducer (CSE) including a top electrode (72) and a radiation conversion layer (70) is disposed over the array. Means are positioned over dead zones between adjacent pixel electrodes to inhibit the accumulation of charge in the radiation conversion layer at the dead zones when the top electrode is biased and the flat panel detector is exposed to radiation. In one embodiment, the inhibiting means is constituted by islands (64) formed of semiconductor material between the array and the radiation transducer. Each island is positioned over a dead zone between adjacent pixel electrodes and contacts a pixel electrode to allow charges accumulated on the islands to drift to the pixel electrodes.