Technical note: Optimization for improved tube-loading efficiency in the dual-energy computed tomography coupled with balanced filter method
- Department of Radiological Technology, School of Health Sciences, Faculty of Medicine, Niigata University, Niigata 951-8518 (Japan)
Purpose: This article describes the spectral optimization of dual-energy computed tomography using balanced filters (bf-DECT) to reduce the tube loadings and dose by dedicating to the acquisition of electron density information, which is essential for treatment planning in radiotherapy. Methods: For the spectral optimization of bf-DECT, the author calculated the beam-hardening error and air kerma required to achieve a desired noise level in an electron density image of a 50-cm-diameter cylindrical water phantom. The calculation enables the selection of beam parameters such as tube voltage, balanced filter material, and its thickness. Results: The optimal combination of tube voltages was 80 kV/140 kV in conjunction with Tb/Hf and Bi/Mo filter pairs; this combination agrees with that obtained in a previous study [M. Saito, ''Spectral optimization for measuring electron density by the dual-energy computed tomography coupled with balanced filter method,'' Med. Phys. 36, 3631-3642 (2009)], although the thicknesses of the filters that yielded a minimum tube output were slightly different from those obtained in the previous study. The resultant tube loading of a low-energy scan of the present bf-DECT significantly decreased from 57.5 to 4.5 times that of a high-energy scan for conventional DECT. Furthermore, the air kerma of bf-DECT could be reduced to less than that of conventional DECT, while obtaining the same figure of merit for the measurement of electron density and effective atomic number. Conclusions: The tube-loading and dose efficiencies of bf-DECT were considerably improved by sacrificing the quality of the noise level in the images of effective atomic number.
- OSTI ID:
- 22096750
- Journal Information:
- Medical Physics, Vol. 37, Issue 8; Other Information: (c) 2010 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-2405
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
61 RADIATION PROTECTION AND DOSIMETRY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
60 APPLIED LIFE SCIENCES
COMPUTERIZED TOMOGRAPHY
DOSIMETRY
EFFICIENCY
ELECTRON DENSITY
ERRORS
IMAGES
KERMA
NOISE
OPTIMIZATION
PERFORMANCE
PHANTOMS
PLANNING
RADIATION DOSES
RADIATION HARDENING
RADIOTHERAPY