A system comprising: a pulsed radiation source; and a radiation detector (100; 8020), the radiation detector comprising: a scintillator (105; 8024) configured to emit a second radiation upon receiving a first radiation from the pulsed radiation source (1000; 8010), a plurality of pixels (150; 8022), wherein each pixel is configured to detect the second radiation; a device configured to detect an intensity of the first radiation from the pulsed radiation source as a function of time, wherein the device is located closer to the pulsed radiation source than the pixels; and a controller; wherein the pulsed radiation source is configured to emit the first radiation during a plurality of ON periods and configured not to emit the first radiation during a plurality of OFF periods; wherein the controller is configured to determine that the pulsed radiation source is at one of the ON periods or at one of the OFF periods based on the intensity of the first radiation detected by the device; wherein the controller is configured to cause the pixels to integrate signals with determination that the radiation source is at one of the ON periods; and wherein the controller is configured to cause the pixels not to integrate signals with determination that the radiation source is at one of the OFF periods. a pulsed radiation source; and a radiation detector (100; 8020), the radiation detector comprising: a scintillator (105; 8024) configured to emit a second radiation upon receiving a first radiation from the pulsed radiation source (1000; 8010), a plurality of pixels (150; 8022), wherein each pixel is configured to detect the second radiation; a device configured to detect an intensity of the first radiation from the pulsed radiation source as a function of time, wherein the device is located closer to the pulsed radiation source than the pixels; and a controller; wherein the pulsed radiation source is configured to emit the first radiation during a plurality of ON periods and configured not to emit the first radiation during a plurality of OFF periods; wherein the controller is configured to determine that the pulsed radiation source is at one of the ON periods or at one of the OFF periods based on the intensity of the first radiation detected by the device; wherein the controller is configured to cause the pixels to integrate signals with determination that the radiation source is at one of the ON periods; and wherein the controller is configured to cause the pixels not to integrate signals with determination that the radiation source is at one of the OFF periods. a scintillator (105; 8024) configured to emit a second radiation upon receiving a first radiation from the pulsed radiation source (1000; 8010), a plurality of pixels (150; 8022), wherein each pixel is configured to detect the second radiation; a device configured to detect an intensity of the first radiation from the pulsed radiation source as a function of time, wherein the device is located closer to the pulsed radiation source than the pixels; and a controller; wherein the pulsed radiation source is configured to emit the first radiation during a plurality of ON periods and configured not to emit the first radiation during a plurality of OFF periods; wherein the controller is configured to determine that the pulsed radiation source is at one of the ON periods or at one of the OFF periods based on the intensity of the first radiation detected by the device; wherein the controller is configured to cause the pixels to integrate signals with determination that the radiation source is at one of the ON periods; and wherein the controller is configured to cause the pixels not to integrate signals with determination that the radiation source is at one of the OFF periods.