Breast Cancer Imaging Using Non-Parallel Beam SPECT

描述（由申请人提供）：该项目的长期目标是开发和评估新的单光子发射计算机断层扫描（SPECT）成像配置，以改进早期乳腺癌放射性药物摄取的表征和量化。配置包括：i)传统的大视场（FOV）相机配备针孔（PinH）或会聚光束（CvB）准直器；ii)新型的中等视场可倾斜相机，配备PinH准直、CvB准直或组合PinH（或CvB）和倾斜平行光束准直。这些相机围绕一个旋转中心旋转，该中心位于一个倾斜的乳房内。本项目的主要假设是小肿瘤（直径< 8mm）的放射性药物摄取的表征和定量。在早期乳腺癌，6:1摄取)可以通过结合：i)适当的三维（3D）轨道配置利用现有的和/或新的核医学SPECT相机；ii) PinH， CvB或组合准直器配置；iii)改进重建算法。本提案的目标不是评估目前可用的用于乳腺癌成像的放射性药物的性能，也不是开发SPECT系统来进行乳腺肿瘤检测的常规筛查。所提出的设计的优点包括：i)通过在大视场相机和/或小型相机上使用PinH准直器实现最小的旋转半径；Ii)由于可能使用多个专门设计的相机和准直器，提高了系统的灵敏度和分辨率；Iii)由于专用乳腺成像轨道减少了光子衰减；以及iv)可倾斜相机，以扩展成像区域以包括乳房的腋窝尾。在第一期项目成果的指导下，5 - 8年级的下一个项目期包括以下具体目标：i)利用现有的临床SPECT系统研究PinH和倾斜的垂直旋转轴CvB准直器配置，用于专用乳腺肿瘤成像；ii)开发和评估新的3D PinH和CvB轨道，以充分或接近充分地采样乳房，包括其腋窝尾；iii)与杰弗逊实验室（JLab）合作开发专用SPECT乳腺成像相机，该相机可进行倾斜相机、3D PinH和CvB轨道，并可作为获取PinH（或可能的CB）/ParH SPECT投影数据的测试平台。在初始项目期间开发的迭代重建程序将得到加强，以包括对PinH和锥束CvB准直器的空间变化分辨率的建模。

DESCRIPTION (provided by applicant): The long-term goal of this project is to develop and evaluate new single photon emission computed tomography (SPECT) imaging configurations for improved characterization and quantification of radiopharmaceutical uptake in early-stage breast cancer. The configurations include: i)conventional, large field of view (FOV) cameras equipped with either pinhole (PinH) or convergent beam (CvB) collimators and ii) novel, medium FOV tiltable cameras, equipped with either PinH collimation, CvB, or combined PinH (or CvB) and tilted-parallel beam collimation. These cameras revolve around a center of rotation located within a pendulous, prone-dependent breast. The main hypothesis of this project is that characterization and quantification of radiopharmaceutical uptake in small tumors (<8 mm dia., 6:1 uptake) during early-stage breast cancer can be achieved by combining: i) appropriate three-dimensional (3D) orbital configurations utilizing available and/or novel nuclear medicine SPECT cameras; ii) PinH, CvB or combined collimator configurations; and iii) improved reconstruction algorithms. It is not a goal of this proposal to evaluate the performance of currently available radiopharmaceuticals used for breast cancer imaging, nor is it a goal to develop a SPECT system to perform routine screening for breast tumor detection. Advantages of the proposed designs include: i) minimal radius of rotation by using PinH collimators on large FOV cameras and/or compact cameras; ii) improved system sensitivity and resolution due to the potential use of multiple specially designed cameras and collimators; iii) reduced photon attenuation due to dedicated breast imaging orbits; and iv) tiltable cameras to extend the imaged region to include the axillary tail of the breast. Guided by the results of the first project period, the next project period in Years 5 - 8 includes the following Specific Aims: i)Investigate PinH and tilted vertical-axis-of-rotation CvB collimator configurations using available clinical SPECT systems for dedicated breast-tumor imaging; ii) Develop and evaluate novel 3D PinH and CvB orbits that sufficiently sample, or nearly sufficiently sample, the breast, including its axillary tail; iii) Develop, in collaboration with Jefferson Laboratory (JLab), a dedicated SPECT breast-imaging camera that performs tilted-camera, 3D PinH and CvB orbits and serves as a test-gantry for acquisition of combined PinH (or possibly CB)/ParH SPECT projection data. The iterative reconstruction programs developed during the initial project period will be enhanced to include modeling spatially varying resolution of PinH and cone beam CvB collimators.