Dual-layer spectral computed tomography: measuring relative electron density

被引：21

作者：

Mei K. ^{[1
]}

Ehn S. ^{[2
]}

Oechsner M. ^{[3
]}

Kopp F.K. ^{[1
]}

Pfeiffer D. ^{[1
,2
]}

Fingerle A.A. ^{[1
]}

Pfeiffer F. ^{[1
,2
]}

Combs S.E. ^{[3
]}

Wilkens J.J. ^{[3
]}

Rummeny E.J. ^{[1
]}

Noël P.B. ^{[1
,2
]}

机构：

[1] Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich

[2] Department of Physics and Munich School of BioEngineering, Technical University of Munich, Munich

[3] Department of Radiation Oncology, Klinikum rechts der Isar, Technical University of Munich, Munich

来源：

European Radiology Experimental | / 2卷 / 1期

关键词：

Absorption (radiation); Dual-layer spectral computed tomography; Electrons; Radiotherapy; Tomography; (x-ray; computed);

D O I：

10.1186/s41747-018-0051-8

中图分类号：

学科分类号：

摘要：

Background: X-ray and particle radiation therapy planning requires accurate estimation of local electron density within the patient body to calculate dose delivery to tumour regions. We evaluate the feasibility and accuracy of electron density measurement using dual-layer computed tomography (DLCT), a recently introduced dual-energy CT technique. Methods: Two calibration phantoms were scanned with DLCT and virtual monoenergetic images (VMIs) at 50 keV and 200 keV were generated. We investigated two approaches to obtain relative electron densities from these VMIs: to fit an analytic interaction cross-sectional model and to empirically calibrate a conversion function with one of the phantoms. Knowledge of the emitted x-ray spectrum was not required for the presented work. Results: The results from both methods were highly correlated to the nominal values (R > 0.999). Except for the water and lung inserts, the error was within 1.79% (average 1.53%) for the cross-sectional model and 1.61% (average 0.87%) for the calibrated conversion. Different radiation doses did not have a significant influence on the measurement (p = 0.348, 0.167), suggesting that the methods are reproducible. Further, we applied these methods to routine clinical data. Conclusions: Our study shows a high validity of electron density estimation based on DLCT, which has potential to improve the procedure and accuracy of measuring electron density in clinical practice. © 2018, The Author(s).

引用

共 22 条

[1] Schneider U., Pedroni E., Lomax A., The calibration of CT Hounsfield units for radiotherapy treatment planning, Phys Med Biol, 41, pp. 111-124, (1996)
[2] Schneider W., Bortfeld T., Schlegel W., Correlation between CT numbers and tissue parameters needed for Monte Carlo simulations of clinical dose distributions, Phys Med Biol, 45, pp. 459-478, (2000)
[3] Yang M., Virshup G., Clayton J., Zhu X.R., Mohan R., Dong L., Theoretical variance analysis of single- and dual-energy computed tomography methods for calculating proton stopping power ratios of biological tissues, Phys Med Biol, 55, pp. 1343-1362, (2010)
[4] Heismann B.J., Leppert J., Stierstorfer K., Density and atomic number measurements with spectral x-ray attenuation method, J Appl Phys, 94, pp. 2073-2079, (2003)
[5] Bazalova M., Carrier J.F., Beaulieu L., Verhaegen F., Dual-energy CT-based material extraction for tissue segmentation in Monte Carlo dose calculations, Phys Med Biol, 53, pp. 2439-2456, (2008)
[6] van Abbema J.K., van Goethem M.J., Greuter M.J., van der Schaaf A., Brandenburg S., van der Graaf E.R., Relative electron density determination using a physics based parameterization of photon interactions in medical DECT, Phys Med Biol, 60, pp. 3825-3846, (2015)
[7] Bourque A.E., Carrier J.F., Bouchard H., A stoichiometric calibration method for dual energy computed tomography, Phys Med Biol, 59, pp. 2059-2088, (2014)
[8] Altman A., Carmi R., TU-E-210A-03: a double-layer detector, dual-energy CT — principles, advantages and applications, Med Phys, 36, (2009)
[9] Doerner J., Hauger M., Hickethier T., Et al., Image quality evaluation of dual-layer spectral detector CT of the chest and comparison with conventional CT imaging, Eur J Radiol, 93, pp. 52-58, (2017)
[10] Sellerer T., Noel P.B., Patino M., Et al., Dual-energy CT: a phantom comparison of different platforms for abdominal imaging, Eur Radiol, 28, pp. 2745-2755, (2018)

← 1 2 3 →