Development of quaity control system of mammographic X-ray unit to decrease patiant dose in mammography

开发乳腺X线摄影机质量控制系统以减少乳腺X线摄影中患者的剂量

• 批准号: 11672242
• 负责人: MATSUMOTO Masao
• 金额: $ 1.98万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11672242/
• 关键词: CdZnTe detector; x-ray spectrum; mammographic x-ray unit; attenuation curve; subject contrast; inherent filter; added filter; CdZnTe半導体検出器

Our purpose is to directly measure mammographic x-ray spectra with collimators and a low-efficiency CdZnTe detector developed recently and to find out the best fit response function of CdZnTe detector to correct the measured spectra. Photon spectra (target Mo or Rh) produced by a mammographic x-ray unit at 25-32 kV and 240 mAs (=3 times of 80 mAs) and transmitted through 0.03 mm Mo or 0.025 mm Rh filter and object (0.1 mm Al to 0.8 mm Al phantoms) have been analyzed. Since detected spectra were distorted by the response of CdZnTe detector and did not present the true photon spectra, the correction was applied by the stripping procedure. The response function of detector used in this procedure has been determined by the evaluation of interactions (K-escape, coherent scattering, and Compton scattering processes) and incomplete charge collection calculated using the Monte Carlo method. We have used K_<α1>, K_<α2>, K_<β1>, K_<β2> radiations of Cd, Zn, and Te, respectively and have used the weight function for the incomplete charge collection and have considered Compton scattering. The Monte Carlo simulations were continued by changing the important factors (mean path length of hole λ_h, dead layer of the CZT crystal and weight factor W_q) of incomplete charge collection until the best fit response function was found out. Corrected photon spectra were compared with the mammographic x-ray spectral data of Bureau of Radiological Health (BRH) measured using a Ge detector. Attenuation curves of aluminum for 25-32 kV were calculated from the corrected photon spectra and compared with the attenuation curves measured using an ionization chamber. These results obtained using the CdZnTe detector agreed with the mammographic x-ray spectral data of BRH and attenuation curves obtained by the ionization chamber.

我们的目的是用准直器和新近研制的低效率的CdZnTe探测器直接测量乳房X-射线能谱，并找出最佳的响应函数来修正测量的光谱。本文分析了在25-32千伏、240毫安(=80毫安的3倍)下，通过0.03 mm钼或0.025 mm Rh滤光片和物体(0.1 mm Al到0.8 mm Al模体)产生的光子谱(靶Mo或Rh)。由于探测到的光谱由于探测器的响应而产生了失真，不能反映真实的光子光谱，因此采用了溶出法进行校正。通过计算相互作用(K逃逸、相干散射和康普顿散射过程)和用蒙特卡罗方法计算的不完全电荷收集，确定了探测器的响应函数。我们分别用Cd、Zn和Te的K&lt；α1&gt；，K_&lt；α2&gt；，K_&lt；β1&gt；，K_&lt；β2&gt；辐射，并用权函数计算了不完全电荷收集，考虑了康普顿散射。通过改变影响不完全电荷收集的重要因素(空穴平均路径长度λ_h、晶体死层和重量因子W_q)继续进行蒙特卡罗模拟，直到找到最佳的响应函数。校正后的光子能谱与放射卫生局(BRH)使用Ge探测器测量的乳房X光能谱数据进行了比较。由修正后的光子谱计算了铝在25-32千伏范围内的衰减曲线，并与电离室测得的衰减曲线进行了比较。用该探测器获得的这些结果与乳腺X射线能谱数据和电离室获得的衰减曲线相吻合。

项目成果

S.MIYASIMA, S.MORIMI, M.MATSUMOTO et al.: "Correction for x-ray spectra measured with the CdZnTe detecter (Japanese)"J.S.Med.Imag.Into.Scie.. Vol.16-2. 79-89 (1999)

S.MIYASIMA、S.MORIMI、M.MATSUMOTO 等人：“用 CdZnTe 探测器测量的 X 射线光谱的校正（日语）”J.S.Med.Imag.Into.Scie.. Vol.16-2。

A.Yamamoto, M.Matsumoto, et.al.: "Analysis of subject contrasts on mammographic X-ray units measured with a CdZnTe detector (Japanese)"J.S.Med.Imag.Inf.Scie.. Vol.17-3. 130-137 (2000)

A.Yamamoto、M.Matsumoto 等人：“使用 CdZnTe 探测器测量的乳房 X 射线单位的受试者对比度分析（日语）”J.S.Med.Imag.Inf.Scie.. Vol.17-3。

宮島悟史,森見左近,松本政雄 他1名: "CdZnTe半導体検出器を用いて測定した診断用領域X線スペクトルの補正"医用画像情報学会雑誌. 16. 79-89 (1999)

Satoshi Miyajima、Sakon Morimi、Masao Matsumoto 和其他 1 人：“使用 CdZnTe 半导体探测器测量的诊断区域 X 射线光谱的校正”医学影像和信息科学学会杂志 16. 79-89 (1999)。

H.Arimura,T.Data,M.Matsumoto,他3名: "Influence of the scattered X-rays on object sharpness of radiograph"Proceedings of SPIE. 3977. 506-513 (2000)

H.Arimura、T.Data、M.Matsumoto 和其他 3 人：“散射 X 射线对射线照片物体清晰度的影响”SPIE 论文集 3977. 506-513 (2000)。

松本政雄,稲邑清也: "フラットパネルディテクタの物理特性について"医学物理. 20・Supp.No.1. 17-42 (2000)

Masao Matsumoto、Kiyoya Inamura：“平板探测器的物理特性”医学物理学 20·Supp.No.1 (2000)。