Water equivalent depth measurement for providing a continuous calibration range based on discrete measurements
First Claim
1. A computer-implemented method for determining a water equivalent depth, between an entrance point and a reference point, of a charged particle beam sent towards a body, wherein said entrance point lies on an external surface of the body, and wherein said reference point corresponds to a location of a charged particle beam detector, the method comprising:
- providing a beam output apparatus for delivering a charged particle beam to said body in a beam direction defined from said entrance point to said reference point;
choosing a maximum energy value such that a charged particle beam, sent by the beam output apparatus and having said maximum energy value and being sent in said beam direction, would penetrate the body from said entrance point up to at least said reference point;
choosing a minimum energy value such that a charged particle beam, sent by the beam output apparatus and having said minimum energy value and being sent in said beam direction, would penetrate the body from said entrance point and would be stopped in said body before reaching said reference point;
sending in said beam direction, from said beam output apparatus, a charged particle beam that is time modulated in energy between said minimum energy value and said maximum energy value;
acquiring, in response to the sent charged particle beam, a time-dependent response of the charged particle beam detector;
calculating a first statistical value reflecting a statistical moment of said time-dependent response;
generating, based on a discrete measurement of a plurality of statistical moments of prior time-dependent responses, a pre-determined calibration curve that expresses a continuous range of water equivalent depths as a function of second statistical values based on the discrete measurement of the plurality of statistical moments of the prior time-dependent responses; and
determining, from said generated pre-determined calibration curve, the water equivalent depth, between the entrance point and the reference point corresponding to the first statistical value, of the charged particle beam output by the beam output apparatus.
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Abstract
A method for determining a water equivalent depth between an entrance point and a reference point is disclosed. The method may comprise sending to a charged particle beam detector placed at a reference point within or beyond a body a charged particle beam whose energy is modulated between a minimum and maximum energy value, acquiring the time dependent response of said charged particle beam detector, determining from said time dependent response a value of a statistical parameter, providing a calibration curve expressing a relationship between values of said statistical parameter and water equivalent depths, and extracting from this calibration curve the water equivalent depth corresponding to the value of the statistical parameter determined from the time dependent response of the charged particle beam detector placed at the reference point.
21 Citations
24 Claims
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1. A computer-implemented method for determining a water equivalent depth, between an entrance point and a reference point, of a charged particle beam sent towards a body, wherein said entrance point lies on an external surface of the body, and wherein said reference point corresponds to a location of a charged particle beam detector, the method comprising:
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providing a beam output apparatus for delivering a charged particle beam to said body in a beam direction defined from said entrance point to said reference point; choosing a maximum energy value such that a charged particle beam, sent by the beam output apparatus and having said maximum energy value and being sent in said beam direction, would penetrate the body from said entrance point up to at least said reference point; choosing a minimum energy value such that a charged particle beam, sent by the beam output apparatus and having said minimum energy value and being sent in said beam direction, would penetrate the body from said entrance point and would be stopped in said body before reaching said reference point; sending in said beam direction, from said beam output apparatus, a charged particle beam that is time modulated in energy between said minimum energy value and said maximum energy value; acquiring, in response to the sent charged particle beam, a time-dependent response of the charged particle beam detector; calculating a first statistical value reflecting a statistical moment of said time-dependent response; generating, based on a discrete measurement of a plurality of statistical moments of prior time-dependent responses, a pre-determined calibration curve that expresses a continuous range of water equivalent depths as a function of second statistical values based on the discrete measurement of the plurality of statistical moments of the prior time-dependent responses; and determining, from said generated pre-determined calibration curve, the water equivalent depth, between the entrance point and the reference point corresponding to the first statistical value, of the charged particle beam output by the beam output apparatus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 18, 19, 23, 24)
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9. A device for determining a water equivalent depth between an entrance point and a reference point of a charged particle beam sent towards a body, wherein said entrance point lies on an external surface of the body, said device comprising:
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a charged particle beam detector that is placed at the reference point; a processor configured to acquire a time-dependent response of said charged particle beam detector from a charged particle beam that is time modulated in energy; a processor configured to calculate a first statistical value reflecting a statistical moment of said time-dependent response response; a processor configured to generate, based on a discrete measurement of a plurality of statistical moments of prior time dependent responses, a pre-determined calibration curve that expresses a continuous range of water equivalent depths as a function of second statistical values based on the discrete measurement of the plurality of statistical moments of the prior time-dependent responses; and a processor configured to determine from said generated pre-determined calibration curve the water equivalent depth corresponding to the first statistical value of the time-dependent response of the charged particle beam detector placed at the reference point. - View Dependent Claims (10, 11, 12, 16, 20)
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13. A method for determining a water equivalent depth between a number of entrance points and a number of corresponding reference points, said entrance points being located on an external surface of a body, said corresponding reference points being points where a corresponding charged particle beam detector is placed, the method, for each entrance point and corresponding reference point, comprising:
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providing a beam output apparatus for delivering a charged particle beam to said body in a beam direction defined from an entrance point to the correspond reference point; choosing a maximum energy value such that a charged particle beam, sent by the beam output apparatus and having said maximum energy value and being sent in said beam direction, would penetrate the body from said entrance point up to at least said reference point; choosing a minimum energy value such that a charged particle beam, sent by the beam output apparatus and having said minimum energy value and being sent in said beam direction, would penetrate the body from said entrance point and would be stopped in said body before reaching said reference point; sending in said beam direction, from said beam output apparatus, a charged particle beam that is time modulated in energy between said minimum energy value and said maximum energy value; acquiring a time-dependent response of the charged particle beam detector; wherein, for each time-dependent response curve obtained for each of the said corresponding detectors, further comprising the steps of; calculating a corresponding statistical value reflecting a statistical moment of the time-dependent response; generating, based on a discrete measurement of a plurality of statistical moments of prior time-dependent responses, a pre-determined calibration curve that expresses a continuous range of water equivalent depths as a function of second statistical values based on the discrete measurement of the statistical moments of the plurality of prior time-dependent responses; and determining from said generated pre-determined calibration curve the water equivalent depth between the entrance point and the reference point corresponding to the corresponding statistical value. - View Dependent Claims (14, 21)
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15. A method for determining range mixing when a water equivalent depth between a number of entrance points and a number of corresponding reference points is being measured using a charged particle beam, said entrance points being located on an external surface of a body, said corresponding reference points being points where a corresponding charged particle beam detector is placed, the method, for each entrance point and corresponding reference point, comprising:
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providing an apparatus for delivering a charged particle beam to said body in a beam direction defined from an entrance point to the correspond reference point; choosing a maximum energy value such that a charged particle beam having said maximum energy value and being sent in said beam direction penetrates the body from said entrance point up to at least said reference point; choosing a minimum energy value such that a charged particle beam having said minimum energy value and being sent in said beam direction penetrates the body from said entrance point and is stopped in said body before reaching said reference point; sending in said beam direction a charged particle beam that is time modulated in energy between said minimum energy value and said maximum energy value; acquiring a time-dependent response of the charged particle beam detector; wherein, for each time-dependent response curve obtained for each of the said corresponding detectors, further comprising the steps of; determining a first statistical value based on a first statistical moment with respect to the time-dependent response curve; comparing the first statistical moment obtained in the previous step with a pre-determined calibration curve that expresses a continuous range of water equivalent depths as a function of second statistical values based on a discrete measurement of statistical moments of a plurality of prior time-dependent responses; computing a range mixing parameter which is an indicator of the observed deviations in the first statistical moment; and classifying the beam detectors according to the range mixing parameter.
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17. A device configured to determine a water equivalent depth between an entrance point and a reference point, said entrance point lying on an external surface of a body, said reference point being a point at which a charged particle beam detector is placed, the device comprising:
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a processor configured to acquire a time-dependent response of said charged particle beam detector from a charged particle beam that is time modulated in energy; a processor configured to calculate a first statistical value reflecting a statistical moment of said time-dependent response; a processor configured to generate, based on a discrete measurement of a plurality of statistical moments of prior time-dependent responses, a pre-determined calibration curve that expresses a continuous range of water equivalent depths as a function of second statistical values based on the discrete measure of the plurality of statistical moments of the prior time-dependent responses; and a processor configured to determine from said generated pre-determined calibration curve the water equivalent depth corresponding to the first statistical value of the time-dependent response of the charged particle beam detector placed at the reference point. - View Dependent Claims (22)
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Specification