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.