Geometric interpretation of the γ dose distribution comparison technique: Interpolation-free calculation.
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| Title: | Geometric interpretation of the γ dose distribution comparison technique: Interpolation-free calculation. |
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| Authors: | Ju, Tao1 taoju@cs.wustl.edu, Simpson, Tim1, Deasy, Joseph O.2, Low, Daniel A.2 |
| Source: | Medical Physics. Mar2008, Vol. 35 Issue 3, p879-887. 9p. 1 Diagram, 5 Graphs. |
| Subjects: | Drug dosage, Medical physics, Radiotherapy, Medical radiology, Biophysics |
| Abstract: | The γ dose comparison tool has been used by numerous investigators to quantitatively compare multidimensional dose distributions. The γ tool requires the specification of dose and distance-to-agreement (DTA) criteria for acceptable variations between the dose distributions. The tool then provides a comparison that simultaneously evaluates the dose difference and distance to agreement of the two dose distributions. One of the weaknesses of the tool is that the comparison requires one of the dose distributions to have a relatively high spatial resolution, with points spaced significantly closer than the DTA criterion. The determination of γ involves an exhaustive search process, so the computation time is significant if an accurate γ is desired. The reason for the need for high spatial resolution lies with the fact that the γ tool measures the closest point in one of the dose distributions (the evaluated distribution) with individual points of the other distribution (the reference distribution) when the two distributions are normalized by the dose difference and DTA criteria for the dose and spatial coordinates, respectively. The closest point in the evaluated distribution to a selected reference distribution point is the value of γ at that reference point. If individual evaluated dose distribution points are compared, the closest point may not accurately reflect the closest value of the evaluated distribution as if it were interpolated on an infinite resolution grid. Therefore, a reinterpretation of the γ distribution as the closest geometric distance between the two distributions is proposed. This is conducted by subdividing the evaluated distribution into simplexes; line segments, triangles, and tetrahedra for one, two, and three-dimensional (3D) dose distributions. The closest distance between any point and these simplexes can be straightforwardly computed using matrix multiplication and inversion without the need of interpolating the original evaluated distribution. While an exhaustive search is still required, not having to interpolate the evaluated distribution avoids the drastic growth of calculation time incurred by interpolation and makes the γ tool more practical and more accurate. In our experiment, the geometric method accurately computes γ distributions between 3D dose distributions on a 200×200×50 grid within two minutes. [ABSTRACT FROM AUTHOR] |
| Copyright of Medical Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Header | DbId: egs DbLabel: Engineering Source An: 31158896 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Geometric interpretation of the γ dose distribution comparison technique: Interpolation-free calculation. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Ju%2C+Tao%22">Ju, Tao</searchLink><relatesTo>1</relatesTo><i> taoju@cs.wustl.edu</i><br /><searchLink fieldCode="AR" term="%22Simpson%2C+Tim%22">Simpson, Tim</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Deasy%2C+Joseph+O%2E%22">Deasy, Joseph O.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Low%2C+Daniel+A%2E%22">Low, Daniel A.</searchLink><relatesTo>2</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Medical+Physics%22">Medical Physics</searchLink>. Mar2008, Vol. 35 Issue 3, p879-887. 9p. 1 Diagram, 5 Graphs. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Drug+dosage%22">Drug dosage</searchLink><br /><searchLink fieldCode="DE" term="%22Medical+physics%22">Medical physics</searchLink><br /><searchLink fieldCode="DE" term="%22Radiotherapy%22">Radiotherapy</searchLink><br /><searchLink fieldCode="DE" term="%22Medical+radiology%22">Medical radiology</searchLink><br /><searchLink fieldCode="DE" term="%22Biophysics%22">Biophysics</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The γ dose comparison tool has been used by numerous investigators to quantitatively compare multidimensional dose distributions. The γ tool requires the specification of dose and distance-to-agreement (DTA) criteria for acceptable variations between the dose distributions. The tool then provides a comparison that simultaneously evaluates the dose difference and distance to agreement of the two dose distributions. One of the weaknesses of the tool is that the comparison requires one of the dose distributions to have a relatively high spatial resolution, with points spaced significantly closer than the DTA criterion. The determination of γ involves an exhaustive search process, so the computation time is significant if an accurate γ is desired. The reason for the need for high spatial resolution lies with the fact that the γ tool measures the closest point in one of the dose distributions (the evaluated distribution) with individual points of the other distribution (the reference distribution) when the two distributions are normalized by the dose difference and DTA criteria for the dose and spatial coordinates, respectively. The closest point in the evaluated distribution to a selected reference distribution point is the value of γ at that reference point. If individual evaluated dose distribution points are compared, the closest point may not accurately reflect the closest value of the evaluated distribution as if it were interpolated on an infinite resolution grid. Therefore, a reinterpretation of the γ distribution as the closest geometric distance between the two distributions is proposed. This is conducted by subdividing the evaluated distribution into simplexes; line segments, triangles, and tetrahedra for one, two, and three-dimensional (3D) dose distributions. The closest distance between any point and these simplexes can be straightforwardly computed using matrix multiplication and inversion without the need of interpolating the original evaluated distribution. While an exhaustive search is still required, not having to interpolate the evaluated distribution avoids the drastic growth of calculation time incurred by interpolation and makes the γ tool more practical and more accurate. In our experiment, the geometric method accurately computes γ distributions between 3D dose distributions on a 200×200×50 grid within two minutes. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Medical Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1118/1.2836952 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 9 StartPage: 879 Subjects: – SubjectFull: Drug dosage Type: general – SubjectFull: Medical physics Type: general – SubjectFull: Radiotherapy Type: general – SubjectFull: Medical radiology Type: general – SubjectFull: Biophysics Type: general Titles: – TitleFull: Geometric interpretation of the γ dose distribution comparison technique: Interpolation-free calculation. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Ju, Tao – PersonEntity: Name: NameFull: Simpson, Tim – PersonEntity: Name: NameFull: Deasy, Joseph O. – PersonEntity: Name: NameFull: Low, Daniel A. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 03 Text: Mar2008 Type: published Y: 2008 Identifiers: – Type: issn-print Value: 00942405 Numbering: – Type: volume Value: 35 – Type: issue Value: 3 Titles: – TitleFull: Medical Physics Type: main |
| ResultId | 1 |
