| 摘要 |
The invention provides a method and system for scanning an object comprising 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. The method comprises irradiating the object with radiation having having a peak energy of at least IMeV, and detecting the first profile radiation after it has interacted with or passed through the object in order to provide information relating to the object. Detecting the first profile radiation comprises detecting the first profile radiation at the first detector region, receiving the first profile radiation that has passed through the first detector region at the second detector region, and detecting the first profile radiation at the second detector region. The scanning method further comprises irradiating the object with radiation having a second energy profile, relatively lower than the first energy profile, and having a peak energy of at least 0.5 MeV, detecting the second profile radiation after it has interacted with or passed through the object in order to provide information relating to the object. Detecting the second profile radiation comprises detecting the second profile radiation at the first detector region, receiving the second profile radiation that has passed through the first detector region at the second detector region, and detecting the second profile radiation at the second detector region. |
