摘要
The measurement of electron density is important for medical diagnosis and charged particle radiotherapy treatment planning.Traditionally,electron density is obtained by CT imaging using the relationship between CT-number and electron densities established beforehand.However,the measurement is not accurate due to the beam hardening effect.In this paper,we propose a simple and practical electron density acquisition method based on dual-energy CT technique.For each sample,the CT imaging is conducted using two selected X-ray energy from synchrotron radiation.A post-processing dual-energy reconstruction method is used.Linear attenuation coefficients of the scanned samples are obtained by FBP reconstruction.The effective atomic number and electron density are got by solving the dual-energy simultaneous equations.Different phantoms and breast tissues were scanned in this experimental study under 10 keV and 30 keV monochromatic X-rays.The distribution of effective atomic numbers and electron densities of the scanned phantoms were obtained by Dual-energy CT image reconstruction,which agrees well with the theoretical values.Compared with conventional methods,the measurement accuracy is greatly improved, and the measurement error is reduced to about 1%.This experimental study demonstrates that DECT imaging based on synchrotron radiation source is applicable to medical diagnosis for quantitative measurement with high accuracy.
The measurement of electron density is important for medical diagnosis and charged particle radiotherapy treatment planning. Traditionally, electron density is obtained by CT imaging using the relationship between CT-number and electron densities established beforehand. However, the measurement is not accurate due to the beam hardening effect. In this paper, we propose a simple and practical electron density acquisition method based on dual-energy CT technique. For each sample, the CT imaging is conducted using two selected X-ray energy from synchrotron radiation. A post-processing dual-energy reconstruction method is used. Linear attenuation coefficients of the scanned samples are obtained by FBP reconstruction. The effective atomic number and electron density are got by solving the dual-energy simultaneous equations. Different phantoms and breast tissues were scanned in this experimental study under 10 keV and 30 keV monochromatic X-rays. The distribution of effective atomic numbers and electron densities of the scanned phantoms were obtained by Dual-energy CT image reconstruction, which agrees well with the theoretical values. Compared with conventional methods, the measurement accuracy is greatly improved, and the measurement error is reduced to about 1%. This experimental study demonstrates that DECT imaging based on synchrotron radiation source is applicable to medical diagnosis for quantitative measurement with high accuracy.
基金
supported by National Key Technology R&D Program of the Ministry of Science and Technology(No.2012BA107B05)
