Gore J C, Maryanski M J, Schulz R J
Department of Diagnostic Radiology, Yale University, New Haven, Connecticut 06520-8042, USA.
Med Phys. 1997 Sep;24(9):1405-8. doi: 10.1118/1.598029.
Radiation-sensitive polymer gels have been adapted for making test objects that can be used to assess the imaging characteristics of magnetic resonance imaging (MRI) systems. The polymer gels contain acrylic monomers within a gel matrix, and when irradiated with x rays the constituents polymerize to produce highly cross-linked microparticles that dramatically affect water NMR relaxation rates where they form. The size of these effects depends on the radiation dose and composition of the mixture irradiated, while the spatial pattern of relaxation time changes can be precisely controlled by spatial modulation of the x-ray exposure. This permits the manufacture of complex test patterns free of susceptibility or edge effects, and overall image performance can be assessed by constructing contrast-detail diagrams using a singly irradiated gel containing areas of different sizes and contrasts. Polymer gels are stable and a variety of different tests objects can be constructed inexpensively. Such materials and test phantoms may find widespread application in diagnostic MRI quality assurance and testing programs.
辐射敏感聚合物凝胶已被用于制造测试对象，可用于评估磁共振成像（MRI）系统的成像特性。聚合物凝胶在凝胶基质中含有丙烯酸单体，当用X射线照射时，其成分会聚合产生高度交联的微粒，这些微粒会显著影响其形成部位的水的核磁共振弛豫率。这些效应的大小取决于辐射剂量和被照射混合物的组成，而弛豫时间变化的空间模式可以通过X射线曝光的空间调制精确控制。这使得能够制造出没有磁化率或边缘效应的复杂测试图案，并且通过使用包含不同尺寸和对比度区域的单次照射凝胶构建对比度-细节图，可以评估整体图像性能。聚合物凝胶很稳定，可以廉价地构建各种不同的测试对象。此类材料和测试体模可能会在诊断MRI质量保证和测试程序中得到广泛应用。
