Development of medical x-ray imaging system using semiconductor array for reduction of patient dose

开发使用半导体阵列的医用 X 射线成像系统以减少患者剂量

• 批准号: 10557239
• 负责人: KANAMORI Hitoshi
• 金额: $ 3.9万
• 依托单位: Fukui University of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10557239/
• 关键词: medical x-ray image; semiconductor array; CdTe semiconductor detector; patient dose; image quality; antiscatter grid; 粒状のウィナースペクトル; 再適撮影条件; 最適撮影条件; 半導体アレイ; エッジ強調効果

(1) Using the traveling heat method for the crystal growth of CdTe semiconductor, uniformity and stability of semiconductor detector array were improved.(2) Digital chest images were made using a CdTe semiconductor detector array having 3000 pixels. The spatial resolution was inferior compared with those made using screen-film systems, but the density resolution was superior. This suggests the utility of the compression of the dynamic range in the image processing.(3) Measurements of x-ray spectra using a CdZnTe semiconductor detector system for 50-150 kV and 25-35 kV x-ray generators were performed.(4) Factors of antiscatter grids (the scatter ratio, the Bucky factor and the contrast improvement fastor) were obtained from scatter and primary x-ray spectra.(5) Small-angle scatter spectra witch were not removed by the grid were obtained. It was suggested that the small angle scatter could not be ignored.(6) Tube voltage dependence of MTF's of screen-film systems were explained by the effect of scattered x rays. A new equation was proposed for thick screens, instead if Rossmann's equation.(7) Threshold radiographic contrasts were considered. Using the psychophysical method, optimum exposure factors and edge enhancement effects were theoretically derived and confirmed by experiments.

(1)采用行热法生长CdTe半导体晶体，提高了半导体探测器阵列的均匀性和稳定性。(2)使用具有3000像素的CdTe半导体探测器阵列制作数字胸部图像。空间分辨率较丝网膜系统低，但密度分辨率高。这说明了动态范围压缩在图像处理中的实用性。(3)利用CdZnTe半导体探测器系统对50- 150kv和25- 35kv x射线发生器进行了x射线光谱测量。(4)从散射谱和一次x射线谱中得到抗散射网格因子（散射比、巴基因子和对比度提升速度）。(5)得到了未被网格去除的小角度散射光谱。指出小角度散射是不可忽视的。(6)用散射x射线的影响解释了屏膜系统MTF的管电压依赖性。提出了一个新的厚屏方程，而不是罗斯曼方程。(7)考虑阈值放射造影对比。运用心理物理学的方法，从理论上推导出最佳暴露因子和边缘增强效应，并通过实验加以验证。

项目成果

H.Arimura: "Evaluation of patient skin doses and signal-to-noise retios of radiographic images in x-ray imaging system"Abstracts of 10^<th> International Congress of The International Radiation Protection. 1. 304 (2000)

H.Arimura：“X 射线成像系统中患者皮肤剂量和放射图像信噪比的评估”第 10 届国际辐射防护大会摘要。

Y.Ozaki, H.Kubota, M.Matsumoto and H.Kanamori: "Experimental verification of optimum density obtained from psychophysical gradients"Imaging Science Journal. 46[2]. 55-57 (1998)

Y.Ozaki、H.Kubota、M.Matsumoto 和 H.Kanamori：“从心理物理梯度获得的最佳密度的实验验证”成像科学杂志。

T.Yamazaki, M.Matsumoto, H.Kanamori et al.: "Analysis of primary x-ray spectrum of CT system"Medical Imaging and Information Sciences. 17[2]. 88-96 (2000)

T.Yamazaki、M.Matsumoto、H.Kanamori等：《CT系统初级X射线能谱分析》医学影像与信息科学。

H.Kanamori: "Evaluation of image noise using psychophysical RMS granularity" Proceedings of the 3^<rd> International Conference on Imaging Science and Hardcopy(Chongqing China). 157-180 (1998)

H.Kanamori：“使用心理物理学RMS粒度评估图像噪声”第三届国际成像科学与硬拷贝会议论文集（中国重庆）。

H.Kanamori: "Optimum tube voltage for chest radiographs obtained by psychophysical analysis"Proceedings of the 2^<nd> Beijing International Congress on Medical Radiation Physics. 1. 99-100 (2000)

H.Kanamori：“心理物理学分析获得的胸片最佳管电压”第二届北京国际医学放射物理大会论文集。