An imaging device , comprising: a first scintillator layer ; an array of detector elements , wherein the array of detector elements comprises a first detector element ; and a second scintillator layer configured to receive radiation after the radiation has passed through the first scintillator layer and the array of detector elements , wherein the array of detector elements is located between the first scintillator layer and the second scintillator layer ; wherein the first detector element is configured to generate a first electrical signal in response to light from the first scintillator layer , and to generate a second electrical signal in response to light from the second scintillator layer ; and wherein the imaging device further comprises: a first electrode located closer to the first scintillator than the second scintillator , and a second electrode situated between the second scintillator and the first detector element , wherein the second electrode is configured to allow the light from the second scintillator layer to reach the first detector element ; characterized in that : the second electrode is made from a non-transparent conductive material but is etched with a pattern to allow light to pass therethrough; or the second electrode comprises a first opening for allowing the light from the second scintillator layer to pass therethrough. a first scintillator layer ; an array of detector elements , wherein the array of detector elements comprises a first detector element ; and a second scintillator layer configured to receive radiation after the radiation has passed through the first scintillator layer and the array of detector elements , wherein the array of detector elements is located between the first scintillator layer and the second scintillator layer ; wherein the first detector element is configured to generate a first electrical signal in response to light from the first scintillator layer , and to generate a second electrical signal in response to light from the second scintillator layer ; and wherein the imaging device further comprises: a first electrode located closer to the first scintillator than the second scintillator , and a second electrode situated between the second scintillator and the first detector element , wherein the second electrode is configured to allow the light from the second scintillator layer to reach the first detector element ; characterized in that : the second electrode is made from a non-transparent conductive material but is etched with a pattern to allow light to pass therethrough; or the second electrode comprises a first opening for allowing the light from the second scintillator layer to pass therethrough. a first electrode located closer to the first scintillator than the second scintillator , and a second electrode situated between the second scintillator and the first detector element , wherein the second electrode is configured to allow the light from the second scintillator layer to reach the first detector element ; characterized in that : the second electrode is made from a non-transparent conductive material but is etched with a pattern to allow light to pass therethrough; or the second electrode comprises a first opening for allowing the light from the second scintillator layer to pass therethrough. the second electrode is made from a non-transparent conductive material but is etched with a pattern to allow light to pass therethrough; or the second electrode comprises a first opening for allowing the light from the second scintillator layer to pass therethrough. <EOS>