Technical note: Optimization for improved tube- loading efficiency in the dual-energy computed tomography coupled with balanced filter method Med
Technical note: Optimization for improved tube- loading efficiency in the dual-energy computed tomography coupled with balanced filter method Med
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技术说明：优化双能计算机断层扫描中提高管加载效率与平衡滤波器方法 Med
DOI：
10.1118/1.3467754
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Masatoshi Saito
中科院分区：
文献类型：
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作者：
Y.Hara;Y.Takada;他6名;松嵜洋子・石沢順子・佐々木玲子;Masatoshi Saito
目的本文描述了使用平衡滤波器 (bf-DECT) 的双能计算机断层扫描的光谱优化，通过致力于获取电子密度信息来减少管负载和剂量，这对于放射治疗的治疗计划至关重要。方法对于 bf-DECT 的光谱优化，作者计算了在 50 厘米直径圆柱形水体模的电子密度图像中达到所需噪声水平所需的束硬化误差和空气比释动能。通过计算可以选择电子束参数，如管电压、平衡滤光片材料及其厚度。结果与 Tb/Hf 和 Bi/Mo 滤光片对结合使用时，管电压的最佳组合为 80 kV/140 kV；该组合与之前的研究[M. Saito，“通过双能计算机断层扫描结合平衡滤波器方法测量电子密度的光谱优化”，Med。物理。 36, 3631–3642 (2009)]，尽管产生最小管输出的过滤器厚度与之前研究中获得的略有不同。目前 bf-DECT 低能量扫描的最终管负载显着降低，从传统 DECT 高能量扫描的 57.5 倍降至 4.5 倍。此外，bf-DECT 的空气比释动能可以降低到低于传统 DECT，同时获得相同的电子密度和有效原子序数测量品质因数。结论通过牺牲有效原子序数图像中的噪声水平质量，bf-DECT 的管加载和剂量效率显着提高。
PurposeThis 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.MethodsFor 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.ResultsThe 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.ConclusionsThe 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.