论文标题
光谱X射线成像检测器的任务依赖性侦探量子效率的归一化
Normalization of the task-dependent detective quantum efficiency of spectroscopic x-ray imaging detectors
论文作者
论文摘要
光谱X射线检测器（SXD）有望在下一代医学X射线成像中发挥重要作用。根据侦探量子效率（DQE）评估其性能，需要通过理想的SXD来归一化频率依赖的信号噪声比（SNR）。我们为量化和检测任务提供了理想SXDS的SNR的数学表达式，并为其标准化任务的数字值制表。我们建议使用标准化的RQA系列X射线光谱。我们将理想的SXD定义为（1）具有无限数量的无限能量箱的SXD，（2）不会扭曲空间或能量域中X射线光子的入射分布，并且（3）不会降低X射线量子入射分布的频率依赖性SNR。我们得出了用于检测和定量任务的理想检测器的噪声功率谱（NP）的分析表达式。我们为RQA X射线光谱的理想SXD的NP制成，以检测和定量铝，PMMA，碘和Gadolinium基材料。我们的分析表明，单个矩阵确定理想SXD在检测和量化任务中的噪声能力，包括伪单源成像的基本材料分解和线综合估计。该NPS矩阵由X射线光谱在检测器上的X射线频谱和一组基材料集的质量分支系数确定。将基本材料的质量分解系数与标准化的RQA X射线光谱相结合，启用了选定光谱和任务的NPS矩阵的数字值。此处报道的理想SXD的NP的数字值和数学表达式可用于将SXDS频率依赖性SNR的测量标准化用于对任务依赖性DQE的实验研究。
Spectroscopic x-ray detectors (SXDs) are poised to play a substantial role in the next generation of medical x-ray imaging. Evaluating their performance in terms of the detective quantum efficiency (DQE) requires normalization of the frequency-dependent signal-to-noise ratio (SNR) by that of an ideal SXD. We provide mathematical expressions of the SNR of ideal SXDs for quantification and detection tasks and tabulate their numeric values for standardized tasks. We propose using standardized RQA-series x-ray spectra. We define ideal SXDs as those that (1) have an infinite number of infinitesimal energy bins, (2) do not distort the incident distribution of x-ray photons in the spatial or energy domains, and (3) do not decrease the frequency-dependent SNR of the incident distribution of x-ray quanta. We derive analytic expressions for the noise power spectrum (NPS) of such ideal detectors for detection and quantification tasks. We tabulate the NPS of ideal SXDs for RQA x-ray spectra for detection and quantification of aluminum, PMMA, iodine, and gadolinium basis materials. Our analysis shows that a single matrix determines the noise power of ideal SXDs in detection and quantification tasks, including basis material decomposition and line-integral estimation for pseudo-mono-energetic imaging. This NPS matrix is determined by the x-ray spectrum incident on the detector and the mass-attenuation coefficients of the set of basis materials. Combining existing tabulated values of the mass-attenuation coefficients of basis materials with standardized RQA x-ray spectra enabled tabulating numeric values of the NPS matrix for selected spectra and tasks. The numeric values and mathematical expressions of the NPS of ideal SXDs reported here can be used to normalize measurements of the frequency-dependent SNR of SXDs for experimental study of the task-dependent DQE.
