Shielding and activity estimator for template-based nuclide identification methods

1. A method for estimating an activity of one or more radio-nuclides, the method comprising:

receiving one or more templates, the one or more templates corresponding to one or more radio-nuclides which contribute to a probable solution;

receiving one or more weighting factors, each weighting factor representing a contribution of one radio-nuclide to the probable solution;

computing an effective areal density for each of the one more radio-nuclides;

computing an effective atomic number (Z) for each of the one more radio-nuclides;

computing an effective metric for each of the one or more radio-nuclides; and

computing, using a processor, an estimated activity for each of the one or more radio-nuclides based at least in part on one or more of:

one or more of the one or more weighting factors;

one or more biasing coefficients;

the effective areal density for each of the one or more radio-nuclides;

the effective atomic number (Z) for each of the one or more radio-nuclides; and

the effective metric for each of the one or more radio-nuclides.

2. The method of claim 1 , further comprising calculating the one or more biasing coefficients for each of the one or more radio-nuclides based on observations of the one or more radio-nuclides, wherein calculating one or more of the effective areal density and the effective atomic number is based at least in part on the one or more biasing coefficients.

3. The method of claim 1 , Wherein computing an effective areal density for each of the one more radio-nuclides comprises:

calculating an areal density biasing coefficient for each of the one or more templates;

multiplying together the weighting factor for each of the one or more radio-nuclides, the areal density biasing coefficient for each of the one or more templates, and an areal density corresponding to each of the one or more templates to obtain a value; and

dividing the value by a sum of the weighting factors for each of the one or more radio-nuclides multiplied by the areal density biasing coefficient for each of the one or more templates.

4. The method of claim 1 , wherein computing an effective atomic number (Z) for each of the one more radio-nuclides comprises:

calculating an effective atomic number (Z) biasing coefficient for each of the one or more radio-nuclides;

multiplying, for each of the one or more radio-nuclides, the weighting factor by the effective atomic number (Z) biasing coefficient by an atomic number (Z) corresponding to each of the one or more templates to obtain a value; and

dividing the value by a sum of the weighting factors multiplied by the effective atomic number (Z) biasing coefficient for each of the one or more radio-nuclides.

5. The method of claim 1 , Wherein computing an effective metric for the one or more radio-nuclides comprises summing each of the effective metrics multiplied by the weighting factor for each of the one or more radio-nuclides.

6. The method of claim 1 , further comprising obtaining a metric per unit activity for the one or more radio-nuclides by using a lookup table comprising shielding materials, shielding atomic number, shielding areal density, and source materials.

7. The method of claim 6 , wherein computing an estimated activity for the one or more radio-nuclides comprises dividing the effective metric by the metric per unit activity to calculate the estimated activity for the one or more radio-nuclides.

8. The method of claim 1 , wherein the effective metric is chosen from a group consisting of dose and total counts.

9. The method as recited in claim 1 , wherein computing an estimated activity for each of the one or more radio-nuclides is detector-independent.

10. The method as recited in claim 1 , further comprising performing multiple linear regression to determine a combination of pre-computed templates having a best fit to an observed spectrum.

11. The method as recited in claim 1 , wherein computing the effective areal density for each of the one or more radio nuclides is based at least in part on one or more of:

an areal density of one or more of the one or more radio-nuclides;

one or more of the one or more weighting factors; and

an areal density biasing coefficient, and

wherein computing the effective atomic number for each of the one or more radio nuclides is based at least in part on one or more of:

an atomic number of one or more of the one or more radio-nuclides;

one or more of the one or more weighting factors; and

a Z biasing coefficient, and

wherein computing the effective areal metric for each of the one or more radio nuclides is based at least in part on one or more of:

a metric fbr one or more of the one or more radio nuclides; and

one or more of the one or more weighting factors.

12. A computer program product for estimating an activity of one or more radio-nuclides, the computer program product comprising:

a non-transitory computer readable medium having computer readable code stored thereon, the computer readable code comprising:

computer readable code configured to receive one or more templates, the one or more templates corresponding to one or more radio-nuclides which contribute to a probable solution;

computer readable code configured to receive one or more weighting factors, each weighting factor representing a contribution of one radio-nuclide to the probable solution;

computer readable code configured to compute an effective areal density for each of the one more radio-nuclides;

computer readable code configured to compute an effective atomic number (Z) for each of the one more radio-nuclides;

computer readable code configured to compute an effective metric for each of the one or more radio-nuclides; and

computer readable code configured to compute an estimated activity for each of the one or more radio-nuclides based at least in part on one or more of:

one or more of the one or more weighting factors;

one or more biasing coefficients;

the effective areal density for each of the one or more radio-nuclides;

the effective atomic number (Z) for each of the one or more radio-nuclides; and

the effective metric for each of the one or more radio-nuclides.

13. The computer program product of claim 12 , wherein the computer readable code further comprises computer readable code configured to calculate one or more biasing coefficients for each of the one or more radio-nuclides based on observations of the one or more radio-nuclides.

14. The computer program product of claim 12 , wherein the computer readable code configured to compute an effective areal density for each of the one more radio-nuclides comprises:

computer readable code configured to calculate an areal density biasing coefficient for each of the one or more templates;

computer readable code configured to multiply together the weighting factor for each of the one or more radio-nuclides, the areal density biasing coefficient for each of the one or more templates, and an areal density corresponding to each of the one or more template to obtain a value; and

computer readable code configured to divide the value by a sum of the weighting factors for each of the one or more radio-nuclides multiplied by the areal density biasing coefficient for each of the one or more templates.

15. The computer program product of claim 12 , wherein the computer readable code configured to compute an effective atomic number (Z) for each of the one more radio-nuclides comprises:

computer readable code configured to calculate an effective atomic number (Z) biasing coefficient for each of the one or more radio-nuclides;

computer readable code configured to multiply, for each of the one or more radio-nuclides, the weighting factor by the effective atomic number (Z) biasing coefficient by an atomic number (Z) corresponding to each of the one or more templates to obtain a value; and

computer readable code configured to divide the value by a sum of the weighting factors for each of the one or more radio-nuclides multiplied by the effective atomic number (Z) biasing coefficient.

16. The computer program product of claim 12 , wherein the computer readable code configured to compute an effective metric for the one or more radio-nuclides comprises computer readable code configured to sum each of the effective metrics multiplied by the weighting factor for each of the one or more radio-nuclides.

17. The computer program product of claim 12 , further comprising computer readable code configured to obtain a metric per unit activity for the one or more radio-nuclides by using a lookup table comprising shielding materials, shielding atomic number, shielding areal density, and source materials.

18. The computer program product of claim 17 , wherein the computer readable code configured to compute an estimated activity for the one or more radio-nuclides comprises computer readable code configured to divide the effective metric by the metric per unit activity to calculate the estimated activity for the one or more radio-nuclides.

19. The computer program product of claim 12 , wherein the effective metric is chosen from a group consisting of dose and total counts.

20. A system for estimating an activity of one or more radio-nuclides, the system comprising:

a processor;

a computer readable memory; and

logic, which when executed by the processor causes the system to:

receive one or more templates, the one or more templates corresponding to one or more radio-nuclides which contribute to a probable solution;

receive one or more weighting factors, each weighting factor representing a contribution of one radio-nuclide to the probable solution;

compute an effective area density for each of the one more radio-nuclides by calculating an areal density biasing coefficient for each of the one or more templates; multiplying together the weighting factor for each of the one or more radio-nuclides, the areal density biasing coefficient for each of the one or more templates, and an areal density corresponding to each of the one or more template to obtain a value; and dividing the value by a sum of the weighting factors for each of the one or more radio-nuclides multiplied by the areal density biasing coefficient for each of the one or more templates;

compute an effective atomic number (Z) for each of the one more radio-nuclides by calculating an effective atomic number (Z) biasing coefficient for each of the one or more radio-nuclides; multiplying, for each of the one or more radio-nuclides, the weighting factor by the effective atomic number (Z) biasing coefficient by an atomic number (Z) corresponding to each of the one or more templates to obtain a value; and dividing the value by a sum of the weighting factors for each of the one or more radio-nuclides multiplied by the effective atomic number (Z) biasing coefficient;

compute an effective metric for each of the one or more radio-nuclides by summing each of the effective metrics multiplied by the weighting factor for each of the one or more radio-nuclides; and

compute an estimated activity for each of the one or more radio-nuclides by dividing the effective metric by a metric per unit activity to calculate the estimated activity for the one or more radio-nuclides.