Patent ID: 9480862
Filing Date: 2016-11-01
CPC Classification: A61N

Claim Text:
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.