Search for novel contrast materials in dual-energy x-ray breast imaging using theoretical modeling of contrast-to-noise ratio
Search for novel contrast materials in dual-energy x-ray breast imaging using theoretical modeling of contrast-to-noise ratio
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DOI：
10.1088/0031-9155/59/15/4311
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发表时间：
2014-08-07
影响因子：
3.5
通讯作者：
Maidment, A. D. A.
中科院分区：
文献类型：
--
作者：
Karunamuni, R.;Maidment, A. D. A.
对比度增强（CE）双能量（DE）X射线乳腺成像使用低能量和高能量X射线光谱对来消除软组织信号变化，从而提高外源性成像剂的可检测性。目前，CEDE乳腺成像使用碘化造影剂进行。这些化合物受到几个缺陷的限制，包括快速清除和肿瘤靶向能力差。这项工作的目的是确定新型造影剂，其对比噪声比（CNR）在乳腺X线摄影能量范围内与碘相当或上级。开发了单能DE减法框架，以计算由低能量和高能量信号强度的对数减法产生的DE信号强度。计算加权因子以去除DE信号对乳房组织的腺体度的依赖性。使用DE信号强度和加权因子，计算10和50 keV之间能量对的原子序数（Z）范围为1至79的材料的CNR。一组原子序数范围为42至63的材料被确定为在乳腺X射线能量范围内表现出最高水平的CNR。这些材料中的几种已被配制成纳米颗粒用于各种应用，但除了碘之外，没有一种被研究为CEDE乳腺成像剂。在这组材料中，LE图像所需的剂量分数随着原子序数的增加而减少。通过减少LE图像的剂量，DE减影技术将不能提供足够质量的解剖图像来伴随造影信息。因此，Z从42到52的材料提供了CNR的几乎最佳值，能量对和剂量分数提供了良好的解剖图像。这项工作旨在激发进一步研究新材料优化CEDE乳腺功能成像。
Contrast-enhanced (CE) dual-energy (DE) x-ray breast imaging uses a low- and high-energy x-ray spectral pair to eliminate soft-tissue signal variation and thereby increase the detectability of exogenous imaging agents. Currently, CEDE breast imaging is performed with iodinated contrast agents. These compounds are limited by several deficiencies, including rapid clearance and poor tumor targeting ability. The purpose of this work is to identify novel contrast materials whose contrast-to-noise ratio (CNR) is comparable or superior to that of iodine in the mammographic energy range. A monoenergetic DE subtraction framework was developed to calculate the DE signal intensity resulting from the logarithmic subtraction of the low- and high-energy signal intensities. A weighting factor is calculated to remove the dependence of the DE signal on the glandularity of the breast tissue. Using the DE signal intensity and weighting factor, the CNR for materials with atomic numbers (Z) ranging from 1 to 79 are computed for energy pairs between 10 and 50 keV.A group of materials with atomic numbers ranging from 42 to 63 were identified to exhibit the highest levels of CNR in the mammographic energy range. Several of these materials have been formulated as nanoparticles for various applications but none, apart from iodine, have been investigated as CEDE breast imaging agents. Within this group of materials, the necessary dose fraction to the LE image decreases as the atomic number increases. By reducing the dose to the LE image, the DE subtraction technique will not provide an anatomical image of sufficient quality to accompany the contrast information. Therefore, materials with Z from 42 to 52 provide nearly optimal values of CNR with energy pairs and dose fractions that provide good anatomical images. This work is intended to inspire further research into new materials for optimized CEDE breast functional imaging.