A scanning method for scanning an object moving in a first direction comprising: irradiating the object with radiation having a peak energy of at least 900 keV, providing a first detector region having a thickness of at least 2 mm and a second detector region having a thickness of at least 5 mm wherein the second detector region is arranged to receive radiation that has passed through the first detector region, detecting the radiation after it has interacted with or passed through the object in order to provide information relating to the object, wherein detecting the radiation comprises: detecting radiation at the first detector region, receiving radiation that has passed through the first detector region at the second detector region, detecting radiation at the second detector region, wherein at the first detector region, the second detector region, or both, detecting the radiation comprises capturing a plurality of sets of detection data using a first group and a second group of detection elements, each detection element being arranged to provide information relating to a corresponding portion of the object, each set of detection data being captured at a different time such that, at a first time, the first group of detection elements is arranged to provide information on the same region of the object as the second group of detection elements at a second time, wherein the first group of detection elements is arranged so that the centres of the detection elements are offset from the centres of the detection elements in the second group in a second direction having a component normal to the first direction. irradiating the object with radiation having a peak energy of at least 900 keV, providing a first detector region having a thickness of at least 2 mm and a second detector region having a thickness of at least 5 mm wherein the second detector region is arranged to receive radiation that has passed through the first detector region, detecting the radiation after it has interacted with or passed through the object in order to provide information relating to the object, wherein detecting the radiation comprises: detecting radiation at the first detector region, receiving radiation that has passed through the first detector region at the second detector region, detecting radiation at the second detector region, detecting radiation at the first detector region, receiving radiation that has passed through the first detector region at the second detector region, detecting radiation at the second detector region, wherein at the first detector region, the second detector region, or both, detecting the radiation comprises capturing a plurality of sets of detection data using a first group and a second group of detection elements, each detection element being arranged to provide information relating to a corresponding portion of the object, each set of detection data being captured at a different time such that, at a first time, the first group of detection elements is arranged to provide information on the same region of the object as the second group of detection elements at a second time, each detection element being arranged to provide information relating to a corresponding portion of the object, each set of detection data being captured at a different time such that, at a first time, the first group of detection elements is arranged to provide information on the same region of the object as the second group of detection elements at a second time, wherein the first group of detection elements is arranged so that the centres of the detection elements are offset from the centres of the detection elements in the second group in a second direction having a component normal to the first direction.