Time-based attenuation compensation
First Claim
1. An exposure control method for controlling an x-ray assembly which generates radiation, comprising the steps of:
- (a) determining a first amount of radiation to be generated by the x-ray assembly and attenuated by a subject;
(b) sampling radiation generated by the x-ray assembly after attenuation of the radiation by the subject;
(c) determining a second amount of radiation from the attenuated radiation sampled in step (b);
(d) determining a first exposure time for the second amount of radiation;
(e) determining whether a condition based on the first amount of radiation, the second amount of radiation, and the first exposure time has been satisfied, wherein the determining step (e) includes the step of using a look-up table to determine a second exposure time for the first amount of radiation based on the first exposure time;
(f) if the condition has not been satisfied, repeating steps (b) through (e) until the condition has been satisfied; and
(g) controlling the generation of radiation by the x-ray assembly based on whether the condition has been satisfied.
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Accused Products
Abstract
A method and apparatus employed in an X-ray apparatus for compensating for attenuation caused by a subject to perform an improved X-ray exposure. A table is created comprising entries accessible via power and attenuation values. Each of the entries includes a first value T representing a time for radiation in the system to reach a base ion count, and a second value C representing an offset ion count from the base ion count. A first set of entries in the table are referenced using a first power setting, and a first base ion count is determined based upon the first power setting, and a maximum radiation exposure is determined for the first power setting and a subject'"'"'s mass. Then, an X-ray emitter is activated until a current ion count from a radiation sampling means has exceeded the base ion count or total radiation emitted has exceeded the maximum radiation allowed for the given mass of a subject. If the current radiation has exceeded the maximum radiation, then the X-ray emitter is deactivated and the process terminates. If the current ion count from the radiation sampling means has exceeded the base ion count, then it is determined whether the base ion count has been offset. If so, then the X-ray emitter is deactivated and the process terminates. If the base ion count has not been offset, then a matching entry is determined from the first set of entries which has the first value T less than or equal to the current exposure. Then, the second value C of the matching entry is added to the base ion count, and the process is repeated until the above conditions are matched.
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Citations
54 Claims
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1. An exposure control method for controlling an x-ray assembly which generates radiation, comprising the steps of:
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(a) determining a first amount of radiation to be generated by the x-ray assembly and attenuated by a subject; (b) sampling radiation generated by the x-ray assembly after attenuation of the radiation by the subject; (c) determining a second amount of radiation from the attenuated radiation sampled in step (b); (d) determining a first exposure time for the second amount of radiation; (e) determining whether a condition based on the first amount of radiation, the second amount of radiation, and the first exposure time has been satisfied, wherein the determining step (e) includes the step of using a look-up table to determine a second exposure time for the first amount of radiation based on the first exposure time; (f) if the condition has not been satisfied, repeating steps (b) through (e) until the condition has been satisfied; and (g) controlling the generation of radiation by the x-ray assembly based on whether the condition has been satisfied. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An exposure control system for controlling an x-ray assembly which generates radiation, comprising:
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(a) means for determining a first amount of radiation to be generated by the x-ray assembly and attenuated by a subject; (b) means for sampling radiation generated by the x-ray assembly after attenuation of the radiation by the subject; (c) means for determining a second amount of radiation from the attenuated radiation sampled by the sampling means; (d) means for determining a first exposure time for the second amount of radiation; (e) means for determining whether a condition based on the first amount of radiation, the second amount of radiation, and the first exposure time has been satisfied, wherein the condition determining means includes means for using a look-up table to determine a second exposure time for the first amount of radiation based on the first exposure time; (g) means for activating the sampling means, the second radiation amount determining means, the first exposure time determining means, and the condition determining means until the condition determining means has determined that the condition has been satisfied; and (h) means for controlling the generation of radiation by the x-ray assembly based on whether the condition has been satisfied. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A system for controlling radiation exposure, comprising:
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(a) an x-ray assembly for generating radiation; (b) means for determining a first amount of radiation to be generated by the x-ray assembly and attenuated by a subject; (c) means for sampling radiation generated by the x-ray assembly after attenuation of the radiation by the subject; (d) means for determining a second amount of radiation from the attenuated radiation sampled by the sampling means; (e) means for determining a first exposure time for the second amount of radiation; (f) means for determining whether a condition based on the first amount of radiation, the second amount of radiation, and the first exposure time has been satisfied, wherein the condition determining means includes means for using a look-up table to determine a second exposure time for the first amount of radiation based on the first exposure time; (g) means for activating the sampling means, the second radiation amount determining means, the first exposure time determining means, and the condition determining means until the condition determining means has determined that the condition has been satisfied; and (h) means for controlling the generation of radiation by the x-ray assembly based on whether the condition has been satisfied. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. An exposure control system for controlling an x-ray assembly which generates radiation, comprising:
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(a) first circuitry for determining a first amount of radiation to be generated by the x-ray assembly and attenuated by a subject; (b) a sampler for sampling radiation generated by the x-ray assembly after attenuation of the radiation by the subject; (c) second circuitry for determining a second amount of radiation from the attenuated radiation sampled by the sampler; (d) third circuitry for determining a first exposure time for the second amount of radiation; (e) fourth circuitry for determining whether a condition based on the first amount of radiation, the second amount of radiation, and the first exposure time has been satisfied, wherein the fourth circuitry includes circuitry for using a look-up table to determine a second exposure time for the first amount of radiation based on the first exposure time; (f) fifth circuitry for activating the sampler, the second circuitry, the third circuitry, and the fourth circuitry until the fourth circuitry has determined that the condition has been satisfied; and (g) sixth circuitry for controlling the generation of radiation by the x-ray assembly based on whether the condition has been satisfied. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
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33. A system for controlling radiation exposure, comprising:
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(a) an x-ray assembly for generating radiation; (b) first circuitry for determining a first amount of radiation to be generated by the x-ray assembly and attenuated by a subject; (c) a sampler for sampling radiation generated by the x-ray assembly after attenuation of the radiation by the subject; (d) second circuitry for determining a second amount of radiation from the attenuated radiation sampled by the sampler; (e) third circuitry for determining a first exposure time for the second amount of radiation; (f) fourth circuitry for determining whether a condition based on the first amount of radiation, the second amount of radiation, and the first exposure time has been satisfied, wherein the fourth circuitry includes circuitry for using a look-up table to determine a second exposure time for the first amount of radiation based on the first exposure time; (g) fifth circuitry for activating the sampler, the second circuitry, the third circuitry, and the fourth circuitry until the fourth circuitry has determined that the condition has been satisfied; and (h) sixth circuitry for controlling the generation of radiation by the x-ray assembly based on whether the condition has been satisfied. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40)
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41. An exposure control method for controlling an x-ray assembly which generates radiation, comprising the steps of:
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(a) determining a first amount of radiation to be generated by the x-ray assembly and attenuated by a subject; (b) sampling radiation generated by the x-ray assembly after attenuation of the radiation by the subject; (c) determining a second amount of radiation from the attenuated radiation sampled in step (b); (d) determining whether a condition has been satisfied based on the first amount of radiation and the second amount of radiation; (e) if the condition has been satisfied, then (i) determining an offset value, and (ii) offsetting the first amount of radiation by the offset value to update the first amount of radiation; (f) repeating steps (b) through (e) until the first amount of radiation has been updated and the condition has been satisfied based on the updated first amount of radiation and the second amount of radiation; and (g) controlling the generation of radiation by the x-ray assembly based on whether the condition has been satisfied based on the updated first amount of radiation and the second amount of radiation. - View Dependent Claims (42, 43, 44, 45, 46, 47)
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48. An exposure control system for controlling an x-ray assembly which generates radiation, comprising:
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(a) first circuitry for determining a first amount of radiation to be generated by the x-ray assembly and attenuated by a subject; (b) a sampler for sampling radiation generated by the x-ray assembly after attenuation of the radiation by the subject; (c) second circuitry for determining a second amount of radiation from the attenuated radiation sampled by the sampler; (d) third circuitry for determining whether a condition has been satisfied based on the first amount of radiation and the second amount of radiation; (e) fourth circuitry for determining an offset value and for offsetting the first amount of radiation by the offset value to update the first amount of radiation if the condition has been satisfied; (f) fifth circuitry for activating the sampler, the second circuitry, the third circuitry, and the fourth circuitry until the first amount of radiation has been updated and the condition has been satisfied based on the updated first amount of radiation and the second amount of radiation; and (g) sixth circuitry for controlling the generation of radiation by the x-ray assembly based on whether the condition has been satisfied based on the updated first amount of radiation and the second amount of radiation. - View Dependent Claims (49, 50, 51, 52, 53, 54)
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Specification