Photon counting CT versus energy-integrating CT: A comparative evaluation of advances in image resolution, noise, and dose efficiency

IF 3.2 2区医学 Q1 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Medical physics Pub Date : 2024-12-19 DOI:10.1002/mp.17591

Björn Heismann, Björn Kreisler, Robert Fasbender

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引用次数: 0

Abstract

Background

Photon counting computed tomography (PCCT) employs direct and spectrally resolved counting of individual x-ray quanta, enhancing image quality compared to the standard energy-integrating CT (EICT).

Purpose

To evaluate the quantitative improvements in CT image quality metrics by comparing the first medical PCCT with a state-of-the-art EICT.

Methods

The PCCT versus EICT noise improvement ratio R was derived from the quantum statistics of the measurement process and measured across the clinical x-ray flux range for both systems. Detector and system modulation transfer functions (MTFs) were obtained using tilted-slit and wire phantom measurements. Image root mean square (RMS) noise, noise power spectrum (NPS), and x-ray patient dose were compared using a CatPhan phantom at two identical clinical target resolutions.

Results

The measurement of the PCCT noise improvement ratio R showed an elimination of electronic noise and a 10% noise transfer advantage. The PCCT detector MTF exhibited 3x higher angular resolution limits in comparison to EICT and close to ideal sinc behavior due to the electromagnetic formation of pixels in the PCCT semiconductor detector. This translated to 3.5x enhancements in CT system MTF ratios at 10 LP/cm, reflecting a significant improvement in millimeter range CT imaging. Both the improved quantum detection and the system MTF ratio improvement contribute to the measured 3x enhancements in image NPS at 10 LP/cm for identical image target resolution. An improvement of up to 1.7x in RMS image noise was observed accordingly. For low and ultra-low dose imaging with image filtering, dose efficiency increased between 2x and 10x, demonstrating the PCCT's capability to advance CT ultra-low dose imaging.

Conclusion

The direct counting detection in PCCT has been shown to significantly improve sinogram noise and detector MTF ratios compared to energy integrating EICT. The observed translations into CT system MTF, image NPS, image noise, and dose ratios reflect a paradigm shift for CT image quality and dose efficiency.

Abstract Image

查看原文本刊更多论文

光子计数CT与能量积分CT：图像分辨率、噪声和剂量效率的比较评价。

背景：光子计数计算机断层扫描（PCCT）采用对单个x射线量子的直接和光谱分辨计数，与标准能量积分CT （EICT）相比，增强了图像质量。目的：通过比较第一个医疗PCCT和最先进的EICT来评估CT图像质量指标的定量改进。方法：根据测量过程的量子统计得出PCCT与EICT的噪声改善比R，并在两种系统的临床x射线通量范围内进行测量。利用斜缝和线模测量获得了探测器和系统调制传递函数（mtf）。图像均方根噪声（RMS）、噪声功率谱（NPS）和x射线患者剂量在两个相同的临床目标分辨率下使用CatPhan幻影进行比较。结果：PCCT噪声改善比R的测量显示消除了电子噪声和10%的噪声传递优势。与EICT相比，PCCT探测器MTF表现出3倍高的角分辨率限制，并且由于PCCT半导体探测器中像素的电磁形成而接近理想的自sinc行为。这意味着在10 LP/cm时，CT系统MTF比提高了3.5倍，反映了毫米范围CT成像的显着改善。改进的量子检测和系统MTF比率的提高都有助于在相同图像目标分辨率下，在10 LP/cm下将图像NPS提高3倍。相应地，RMS图像噪声的改善高达1.7倍。对于带图像滤波的低剂量和超低剂量成像，剂量效率提高了2 - 10倍，证明了PCCT推进CT超低剂量成像的能力。结论：与能量积分EICT相比，PCCT中直接计数检测可显著改善sinogram noise和检测器MTF比率。观察到的CT系统MTF、图像NPS、图像噪声和剂量比的转换反映了CT图像质量和剂量效率的范式转变。

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

Medical physics 医学-核医学

CiteScore

6.80

自引率

15.80%

发文量

660

审稿时长

1.7 months

期刊介绍： Medical Physics publishes original, high impact physics, imaging science, and engineering research that advances patient diagnosis and therapy through contributions in 1) Basic science developments with high potential for clinical translation 2) Clinical applications of cutting edge engineering and physics innovations 3) Broadly applicable and innovative clinical physics developments Medical Physics is a journal of global scope and reach. By publishing in Medical Physics your research will reach an international, multidisciplinary audience including practicing medical physicists as well as physics- and engineering based translational scientists. We work closely with authors of promising articles to improve their quality.