Adaptive scanning in an imaging system
View Patent ↗An object within a region is exposed to a first beam of penetrating radiation. The first beam of penetrating radiation is sensed on a side opposite the region from a source of the first beam. An attenuation of the first beam caused by passing the first beam through the object is determined, the attenuation is compared to a threshold attenuation. If the attenuation exceeds the threshold attenuation, a parameter of a second of beam of penetrating radiation is adjusted based on the determined attenuation.
1. An imaging system for adaptively scanning a region with a beam of radiation, the imaging system comprising:
a source system comprising:
a first source of radiation configured to direct a pre-screen beam toward a region, and
a second source of radiation configured to direct a main beam toward the region after the first source directs the pre-screen beam toward the region, the pre-screen beam and the main beam being spatially separated with respect to the region such that the pre-screen beam scans a portion of the region before the main beam scans the portion of the region;
a sensor configured to:
sense radiation from the pre-screen beam, and
produce a representation of the sensed radiation;
a controller coupled to the source system and configured to:
receive the representation of the sensed radiation,
determine, from the representation, an amount of attenuation of the pre-screen beam caused by the region,
adjust a parameter of the main beam based on the determined attenuation prior to directing the main beam toward the region;
receive a representation of the sensed scattered radiation,
determine an amount of scattered radiation based on the representation,
compare the amount of scattered radiation to a threshold, and
if the amount of scattered radiation meets or exceeds the threshold, reduce an intensity of one or more of the pre-screen beam or the main beam.
2. The system of claim 1 , wherein the pre-screen beam is a beam of x-ray radiation, and the main beam is a beam of x-ray radiation having a greater intensity of radiation than the pre-screen beam.
3. The system of claim 1 , wherein the main beam is a pulsed x-ray beam.
4. The system of claim 3 , further comprising a filter wheel coupled to the controller and positioned between the second source and the object, the filter wheel including a material configured to adjust an intensity or adjust a spectral energy of radiation passing through the material.
5. The system of claim 1 , wherein the pre-screen beam scans the region at a different angle than the main beam.
6. The system of claim 1 , wherein the pre-screen beam comprises penetrating radiation of a first energy, and the main beam comprises penetrating radiation of a second energy, the first energy and the second energy being different.
7. The system of claim 1 , further comprising a scattered radiation monitor coupled to the controller, the scattered radiation monitor being configured to sense radiation scattered from the region.
8. The system of claim 1 , wherein the controller being configured to adjust a parameter of the main beam based on the determined attenuation comprises the controller causing an intensity of the main beam to increase or decrease.
9. The system of claim 1 , wherein the controller being configured to adjust a parameter of the main beam based on the determined attenuation comprises the controller causing a change in a spectral energy of the main beam.
10. The system of claim 1 , further comprising a filter positioned in a path of the main beam, the filter configured to adjust an intensity or spectral energy of a portion of the main beam that passes through the filter.
11. The system of claim 10 , wherein the filter comprises a thickness that varies in a direction of propagation of the main beam.
12. A method of adaptive scanning, the method comprising:
directing a pre-screen beam of penetrating radiation towards a region, the pre-screen beam being directed from a first source of radiation;
determining an amount of attenuation of the pre-screen beam;
adjusting a parameter of a main beam of penetrating radiation based on the amount of attenuation of the pre-screen beam;
directing the adjusted main beam of penetrating radiation towards the region, the main beam being directed from a second source of radiation that is spatially separated from the first source of radiation such that the pre-screen beam scans the region before the main beam scans the region;
receiving a representation of an amount of scattered radiation;
determining an amount of scattered radiation;
comparing the amount of scattered radiation to a threshold; and
if the amount of scattered radiation meets or exceeds the threshold, adjusting a parameter of the main beam of penetrating radiation based on the amount of attenuation of the pre-screen beam comprises adjusting an intensity of the main beam such that the amount of scattered radiation is below the threshold.
13. The method of claim 12 , wherein the pre-screen beam is an x-ray beam, and the main beam is an x-ray beam, the main beam having a greater intensity than the pre-screen beam.
14. The method of claim 13 , wherein one or more of the pre-screen beam or the main beam are pulsed beams.
15. The method of claim 12 , wherein adjusting a parameter of the main beam comprises adjusting a source of the main beam such that an intensity of the main beam is changed.
16. The method of claim 12 , further comprising:
receiving a representation of the adjusted main beam as attenuated by passing through the region; and
generating an image of the region based on the received representation.
17. The method of claim 12 , wherein adjusting a parameter of a main beam of penetrating radiation based on the amount of attenuation of the pre-screen beam comprises directing the main beam through a filter positioned between a source of the main beam and the region, the filter being configured to adjust an intensity or spectral energy of the main beam.
18. The method of claim 12 , wherein directing the adjusted main beam towards the region comprises directing the main beam of radiation towards the region at a different angle than directing the pre-screen beam of radiation.
19. A method comprising:
directing a pre-screen beam of penetrating radiation towards a region;
determining an amount of attenuation of the pre-screen beam;
adjusting a parameter of a main beam of penetrating radiation based on the amount of attenuation of the pre-screen beam;
directing the adjusted main beam of penetrating radiation towards the region, the pre-screen beam and the main beam being spatially separated such that the pre-screen beam scans the region before the main beam scans the region;
receiving a representation of an amount of scattered radiation;
determining an amount of scattered radiation;
comparing the amount of scattered radiation to a threshold, and
if the amount of scattered radiation meets or exceeds the threshold, adjusting a parameter of the main beam of penetrating radiation based on the amount of attenuation of the pre-screen beam comprises adjusting an intensity of the main beam such that the amount of scattered radiation is below the threshold.