Optimization of energy windows to calculate quantitative X-ray images using an energy-resolving photon-counting detector: A simulation study

IF 2.8 3区物理与天体物理 Q3 CHEMISTRY, PHYSICAL

Radiation Physics and Chemistry Pub Date : 2024-12-04 DOI:10.1016/j.radphyschem.2024.112460

Rina Nishigami , Daiki Kobayashi , Natsumi Kimoto , Takashi Asahara , Tatsuya Maeda , Tomonobu Haba , Yuki Kanazawa , Shuichiro Yamamoto , Hiroaki Hayashi

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引用次数: 0

Abstract

Purpose

Energy-resolving photon-counting detectors (ERPCDs) are expected to enable novel functional diagnosis using quantitative X-ray images such as effective atomic number (Z_eff) images. In this simulation study, we sought to optimize the settings related to tube voltage and energy windows.

Methods

We assumed a virtual phantom composed of polymethylmethacrylate (PMMA, Z_eff = 6.5) and aluminum (Z_eff = 13.0), and simulated the conventional energy integrating detector (EID) image and Z_eff images obtained by the ERPCD. The investigational phantom is composed of elements with ρt ranging from 0.1 to 80 g/cm². In order to perform optimization using a quantitative index, we defined a system performance function (SPF) that takes into account the contributions of the contrast to noise ratio (CNR) of the EID image and the uncertainty (

δ Z_{eff}

) of the Z_eff image. The tube voltage was varied to be 60, 90, and 120 kV, and the variable that determines the separation energy between the middle and high energy windows was changed from 35 to 115 keV with 5 keV interval. In addition, preclinical images of the digital phantoms based on computed tomography (CT) images were created for demonstration.

Results

We were able to determine the imaging conditions that yielded the better image quality for tube voltages of 60, 90, and 120 kV. Among these, the 120 kV condition (20-30-50-120 keV) showed the smallest SPF value, and was therefore adopted as the optimal condition. Furthermore, high-quality EID and Z_eff images of preclinical phantoms were obtained under the optimal condition.

Conclusions

We determined the optimal condition suitable for deriving both qualitative and quantitative images using ERPCDs.

Abstract Image

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优化能量窗口，利用能量分辨光子计数探测器计算定量 X 射线图像：模拟研究

能量分辨光子计数探测器（ERPCDs）有望使用定量x射线图像（如有效原子序数（Zeff）图像）实现新的功能诊断。在这项模拟研究中，我们试图优化与管电压和能量窗口相关的设置。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Radiation Physics and Chemistry 化学-核科学技术

CiteScore

5.60

自引率

17.20%

发文量

574

审稿时长

12 weeks

期刊介绍： Radiation Physics and Chemistry is a multidisciplinary journal that provides a medium for publication of substantial and original papers, reviews, and short communications which focus on research and developments involving ionizing radiation in radiation physics, radiation chemistry and radiation processing. The journal aims to publish papers with significance to an international audience, containing substantial novelty and scientific impact. The Editors reserve the rights to reject, with or without external review, papers that do not meet these criteria. This could include papers that are very similar to previous publications, only with changed target substrates, employed materials, analyzed sites and experimental methods, report results without presenting new insights and/or hypothesis testing, or do not focus on the radiation effects.