Breast Cancer Imaging Using Non-Parallel Beam SPECT

描述（由申请人提供）：本项目的长期目标是开发和评价新的单光子发射计算机断层扫描（SPECT）成像配置，以改善早期乳腺癌放射性药物摄取的表征和定量。这些配置包括：i）配备有针孔（PinH）或会聚光束（CvB）准直器的常规大视场（FOV）相机，以及ii）新型中等FOV可倾斜相机，配备有PinH准直、CvB或组合的PinH（或CvB）和倾斜平行光束准直。这些摄像机围绕位于下垂的、俯卧的乳房内的旋转中心旋转。该项目的主要假设是小肿瘤（直径<8 mm，在早期乳腺癌期间，可以通过组合以下各项来实现（例如，6：1摄取）：i）利用可用和/或新型核医学SPECT相机的适当三维（3D）轨道配置; ii）PinH、CvB或组合的准直器配置;以及iii）改进的重建算法。本提案的目的不是评价目前可用于乳腺癌成像的放射性药物的性能，也不是开发SPECT系统以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FOV相机和/或紧凑型相机上使用PinH准直器来实现最小的旋转半径; ii）由于多个专门设计的相机和准直器的潜在使用而提高的系统灵敏度和分辨率; iii）由于专用的乳房成像轨道而减少的光子衰减;以及iv）可倾斜的相机，以将成像区域扩展到包括乳房的腋尾。在第一个项目周期结果的指导下，第5 - 8年的下一个项目周期包括以下具体目标：i）使用现有的临床SPECT系统研究PinH和倾斜垂直旋转轴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，其充分采样或几乎充分采样乳房，包括其腋尾; iii）与Jefferson实验室（JLab）合作开发专用SPECT乳房成像相机，该相机可执行倾斜相机、3D PinH和CvB轨道，并作为测试台架用于采集组合PinH（或可能CB）/ParH SPECT投影数据。在项目初期开发的迭代重建程序将得到增强，以包括PinH和锥形束CvB准直器的空间变化分辨率建模。

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.