Radiation scanning units including a movable platform

• US 20090067575A1
• Filed: 04/07/2008
• Published: 03/12/2009
• Est. Priority Date: 07/24/2002
• Status: Active Grant

• Current Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Original Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Inventors: Seppi, Edward E., Ford, John, Marc, Marcel
• Granted Patent: US 8,000,436 B2
• Time in Patent Office: Days
• US Class Current: 378/57
• CPC Class Codes: G01N 2223/419 computed tomograph
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: G01V 5/226 using tomography

Abstract

A scanning unit for inspecting objects comprises in one example a radiation source, a movable platform to support an object, and a detector positioned to receive radiation after interaction of radiation with the object. The platform is movable at least partially within a cavity defined, at least partially, below at least one of the source or the detector. In another scanning unit, a first conveyor conveys an object to a movable platform, and second and third conveyors convey the object from the platform. The second and third conveyors are at different vertical heights. In another scanning unit, images from an energy sensitive detector and a spatial detector are fused. In a method, scanning parameters during CT scanning are changed and images reconstructed before and after the change. In another method, an object is scanned with X-ray beams having first and second energy distributions, generated by the same X-ray source.

Claims

1. A scanning unit for inspecting objects, comprising:

a movable platform to support an object;

a radiation source to emit a beam of radiation toward the object;

a detector positioned to receive radiation after interaction with object;

wherein the platform is movable at least partially within a cavity defined, at least in part, below at least one of the source or the detector.

2. The scanning unit of claim 1, wherein the source is a source of X-ray radiation.

3. The scanning unit of claim 1, wherein the detector is aligned with the source to detect radiation transmitted through the object.

4. The scanning unit of claim 1, further comprising means for moving the platform along a substantially vertical axis, at least partially within the cavity.

5. The scanning unit of claim 1, further comprising a first conveyor to convey the cargo conveyance to the platform for scanning.

6. The scanning unit of claim 5, further comprising a second conveyor to convey the object from the platform after scanning.

7. The scanning unit of claim 6, wherein the platform is rotatable, the system further comprising:

a third conveyor to convey the object from the platform after scanning;

wherein the rotatable platform is selectively configured to direct an object to the second or third platform, after scanning.

8. The scanning unit of claim 1, further comprising a second radiation source to emit a second radiation beam;

wherein the first radiation source emits a first radiation beam having a first energy distribution and the second radiation source emits a second radiation beam having a second energy distribution different than the first energy distribution.

9. The scanning unit of claim 8, wherein the first energy distribution has a peak in the MeV range and the second energy distribution has a peak in the KeV range.

10. The scanning unit of claim 8, further comprising:

a second, energy sensitive, detector; and

at least one processor electrically coupled to the second detector, the at least one processor being further configured to;

reconstruct energy based images based on data received from the second detector; and

fuse images based on data from the first detector with the images based on the data received from the second detector.

11. The scanning unit of claim 9, wherein the first detector is between the second detector and the radiation source.

12. The scanning unit of claim 1, wherein the radiation source is operational to be selectively switched between emitting a radiation beam having a first energy distribution and a radiation beam having a second energy distribution different than the first energy distribution.

13. The scanning unit of claim 1, wherein the detector array comprises:

spatial detector elements; and

energy sensitive detector elements.

14. The scanning unit of claim 1, wherein the cavity is defined, at least in part, by ground.

15. A scanning unit for inspecting objects, comprising:

at least one source of penetrating radiation to emit a beam of radiation to scan an object;

a movable platform to support an object during scanning by the beam of radiation;

at least one detector positioned to receive radiation after interaction with the object;

a first conveyor to convey the object to the platform for scanning;

a second conveyor to convey the object from the platform after scanning, the second conveyor being at a first vertical height; and

a third conveyor to convey the object from the platform after scanning, the third conveyor being at a second vertical height different than the first vertical height;

wherein the platform is configured to selectively direct the object to one of the second conveyor or the third conveyor by moving the platform between the first height and the second height.

16. The scanning unit of claim 15, further comprising a processor configured to cause movement of the platform between the first height and second height to align the object with the second conveyor if the object passes inspection and to align the object with the third conveyor if the object has not passed inspection.

17. The scanning unit of claim 16, further comprising:

a fourth conveyor to selectively convey the object from the platform after scanning and return the object to the platform for rescanning;

wherein the platform is rotatably positionable to selectively align the object with one of the second conveyor and the fourth conveyor.

18. The scanning unit of claim 17, wherein the second conveyor and the fourth conveyor are at the first vertical height.

19. A scanning unit for inspecting objects, comprising:

a platform to support an object;

at least one radiation source to emit a beam of radiation;

a first, energy sensitive detector positioned to detect radiation after interaction with the object;

a second, spatial detector positioned to receive radiation after interaction of the beam with the object; and

at least one processor configured to;

fuse at least certain of the first and second images generated from radiation detected by the first, energy sensitive detector and the second, spatial detector, respectively.

20. The system of claim 19, wherein the processor is configured to:

reconstruct at least one first image of at least a portion of the object, during operation, based, at least in part, on the detected radiation from the first, energy sensitive detector; and

reconstruct at least one second computed tomographic image of at least a portion of the object, during operation, based, at least in part, on the detected radiation from the first, second detector.

21. The system of claim 20, wherein at least one of the source or the detector is movable at least partially around the object.

22. The system of claim 20, wherein the platform is rotatable about an axis and at least one of the source, the platform or the detector is movable in a direction along a direction of the axis.

23. The system of claim 19, wherein at least one of the source, the platform or the detector is movable in a direction along a direction of the axis.

24. The system of claim 19, wherein the second, spatial detector is between the first, energy sensitive detector and the radiation source.

25. A method of examining contents of an object, comprising:

scanning an object with a radiation beam;

detecting radiation transmitted through the object with a first, spatial detector;

detecting radiation transmitted through the object with a second, energy sensitive, detector;

generating first images from radiation detected by the first detector;

generating second images from radiation detected by the second detector; and

fusing at least some of the first and second images.

26. The method of claim 25, wherein the second energy sensitive detector is behind the first detector.

27. The method of claim 25, comprising reconstructing computed tomographic images from radiation detected by the first detector.

28. The method of claim 27, further comprising moving at least one of the source or the detector at least partially around the object.

29. A method of examining contents of an object, comprising:

conducting a first computed tomographic scan of the object;

reconstructing at least one first computed tomographic image based on the first computed tomographic scan;

changing a scanning parameter;

conducting a second computed tomographic scan of the object after changing the scanning parameter; and

reconstructing at least one second computed tomographic image based on the second computed tomographic scan.

30. The method of claim 29, wherein the object is rotated and the scanning parameter comprises rotation speed of the object, the method further comprising:

rotating the object during the first computed tomographic scan, at a first speed and

rotating the object during the second computed tomographic scan at a second rotation speed different from the first speed.

31. The method of claim 29, wherein the object is moved along an axis and the scanning parameter comprises movement speed along the axis, the method further comprising:

conducting the first computed tomographic scan while moving the object along the axis at a first speed; and

conducting the second computed tomographic scan while moving the object along the axis at a second speed different than the first speed.

32. The method of claim 29, wherein the scanning parameter comprises dose rate, the method further comprising:

conducting the first computed tomographic scan at a first dose rate; and

conducting the second computed tomographic scan at a second dose rate different than the first dose rate.

33. The method of claim 29, wherein the scanning parameter comprises radiation energy distribution, the method comprising:

conducting the first computed tomographic scan at a first radiation energy distribution; and

conducting the second computed tomographic scan at a second energy distribution different than the first energy distribution.

34. The method of claim 33, further comprising:

conducting the first computed tomographic scan at the first energy distribution while the object is being moved in a first direction; and

conducting the second computed tomographic scan at the second energy distribution while the object is being moved in a second direction different than the first direction.

35. The method of claim 34, wherein the first direction is up and the second direction is down.

36. A method for inspecting objects, comprising:

scanning an object with a first beam of X-ray radiation from a radiation source, the first radiation beam having a first energy distribution;

detecting first radiation after the first radiation beam interacts with the object;

generating a first image based on the first detected radiation;

causing the radiation source to generate a second beam of X-ray radiation, the second radiation beam having a second energy distribution different from the first energy distribution;

scanning the object with the second radiation beam from the radiation source;

detecting second radiation after the second beam interacts with the object; and

generating a second image based on the second detected radiation.