A parametrization of the CT number of a substance and its use for stoichiometric calibration
| Autor: | César Rodríguez Rodríguez, Maria J. Manzanas, A. Calzado, Rosa Gilarranz, Luis Carlos Martínez |
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| Rok vydání: | 2012 |
| Předmět: |
Photons
Electron density Mathematical optimization Photon Radiotherapy Planning Computer-Assisted Biophysics General Physics and Astronomy General Medicine Imaging phantom Computational physics Calibration Linear Models Range (statistics) Radiology Nuclear Medicine and imaging Tomography X-Ray Computed Parametrization Effective atomic number Beam (structure) Mathematics |
| Zdroj: | Physica Medica. 28:33-42 |
| ISSN: | 1120-1797 |
| DOI: | 10.1016/j.ejmp.2011.02.001 |
| Popis: | A method to carry out stoichiometric calibrations of CT scanners employed in radiotherapy treatment planning is proposed. The method is based on a simple parametrization of the CT number of a substance, which involves only two variables to describe the substance (electron density and one effective atomic number) and one parameter to describe the beam. The method was tested experimentally on a group of beams. A set of no tissue-like substances of known densities and elemental compositions were employed as calibrators. CT number-to-density curves (RED curves) were calculated with the proposed parametrization and compared to those measured with a commercial density phantom. Differences between the electron densities assigned by the calculated RED curves and the measured ones were in the range 0.009-0.019 (RMS). The proposed method may be employed to carry out accurate stoichiometric calibrations by using only one suitable substance as calibrator, not necessarily tissue-like. |
| Databáze: | OpenAIRE |
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