PDF(Pubmed)
Abstract：
UNASSIGNED: Photon counting CT (PCCT) provides spectral measurements for material decomposition. However, the image noise (at a fixed dose) depends on the source spectrum. Our study investigates the potential benefits from spectral optimization using fast kV switching and filtration to reduce noise in material decomposition.
UNASSIGNED: The effect of the input spectra on noise performance in both two-basis material decomposition and three-basis material decomposition was compared using Cramer-Rao lower bound analysis in the projection domain and in a digital phantom study in the image domain. The fluences of different spectra were normalized using the CT dose index to maintain constant dose levels. Four detector response models based on Si or CdTe were included in the analysis.
UNASSIGNED: For single kV scans, kV selection can be optimized based on the imaging task and object size. Furthermore, our results suggest that noise in material decomposition can be substantially reduced with fast kV switching. For two-material decomposition, fast kV switching reduces the standard deviation (SD) by ∼ 10 % . For three-material decomposition, greater noise reduction in material images was found with fast kV switching (26.2% for calcium and 25.8% for iodine, in terms of SD), which suggests that challenging tasks benefit more from the richer spectral information provided by fast kV switching.
UNASSIGNED: The performance of PCCT in material decomposition can be improved by optimizing source spectrum settings. Task-specific tube voltages can be selected for single kV scans. Also, our results demonstrate that utilizing fast kV switching can substantially reduce the noise in material decomposition for both two- and three-material decompositions, and a fixed Gd filter can further enhance such improvements for two-material decomposition.
UNASSIGNED: The effect of the input spectra on noise performance in both two-basis material decomposition and three-basis material decomposition was compared using Cramer-Rao lower bound analysis in the projection domain and in a digital phantom study in the image domain. The fluences of different spectra were normalized using the CT dose index to maintain constant dose levels. Four detector response models based on Si or CdTe were included in the analysis.
UNASSIGNED: For single kV scans, kV selection can be optimized based on the imaging task and object size. Furthermore, our results suggest that noise in material decomposition can be substantially reduced with fast kV switching. For two-material decomposition, fast kV switching reduces the standard deviation (SD) by ∼ 10 % . For three-material decomposition, greater noise reduction in material images was found with fast kV switching (26.2% for calcium and 25.8% for iodine, in terms of SD), which suggests that challenging tasks benefit more from the richer spectral information provided by fast kV switching.
UNASSIGNED: The performance of PCCT in material decomposition can be improved by optimizing source spectrum settings. Task-specific tube voltages can be selected for single kV scans. Also, our results demonstrate that utilizing fast kV switching can substantially reduce the noise in material decomposition for both two- and three-material decompositions, and a fixed Gd filter can further enhance such improvements for two-material decomposition.
摘要：
■光子计数CT（PCCT）为材料分解提供光谱测量。然而,图像噪声（在固定剂量）取决于源频谱。我们的研究调查了使用快速kV开关和过滤来降低材料分解噪声的光谱优化的潜在好处。
■使用投影域中的Cramer-Rao下界分析和图像域中的数字体模研究，比较了输入光谱对两基材料分解和三基材料分解中噪声性能的影响。使用CT剂量指数对不同光谱的通量进行归一化，以保持恒定的剂量水平。分析中包括基于Si或CdTe的四种检测器响应模型。
■对于单千伏扫描，kV选择可以基于成像任务和对象尺寸进行优化。此外，我们的结果表明，在材料分解的噪声可以大大减少与快速kV开关。对于两种材料的分解，快速kV切换将标准偏差(SD)降低了10%。对于三物质分解，通过快速kV切换，材料图像中的噪声降低更大（钙为26.2％，碘为25.8％，就SD而言)，这表明，具有挑战性的任务受益于更丰富的频谱信息提供了快速kV开关。
■可以通过优化源频谱设置来提高PCCT在材料分解中的性能。可以为单个kV扫描选择特定任务的管电压。此外，我们的结果表明，利用快速kV开关可以大大降低噪声在材料分解的二和三材料分解，和固定的Gd滤波器可以进一步增强双材料分解的这种改进。
■使用投影域中的Cramer-Rao下界分析和图像域中的数字体模研究，比较了输入光谱对两基材料分解和三基材料分解中噪声性能的影响。使用CT剂量指数对不同光谱的通量进行归一化，以保持恒定的剂量水平。分析中包括基于Si或CdTe的四种检测器响应模型。
■对于单千伏扫描，kV选择可以基于成像任务和对象尺寸进行优化。此外，我们的结果表明，在材料分解的噪声可以大大减少与快速kV开关。对于两种材料的分解，快速kV切换将标准偏差(SD)降低了10%。对于三物质分解，通过快速kV切换，材料图像中的噪声降低更大（钙为26.2％，碘为25.8％，就SD而言)，这表明，具有挑战性的任务受益于更丰富的频谱信息提供了快速kV开关。
■可以通过优化源频谱设置来提高PCCT在材料分解中的性能。可以为单个kV扫描选择特定任务的管电压。此外，我们的结果表明，利用快速kV开关可以大大降低噪声在材料分解的二和三材料分解，和固定的Gd滤波器可以进一步增强双材料分解的这种改进。
