BREAST CANCER IMAGING USING NONPARALLEL BEAM SPECT

描述(改编自申请者摘要)：该项目的长期目标 研究项目是开发新的单光子发射计算机 用于改进成像和表征的断层扫描(SPECT)系统设计 早期乳腺癌对~(99m)Tc-放射性药物摄取的研究这个 正在考虑的概念有多个可倾斜的摄像头，配备 会聚光束或针孔准直器，围绕单乳房旋转， 患者处于俯卧位，与摄像机的垂直方向对齐 旋转轴(VAOR)。主要假设是一个多摄像机VAOR 会聚光束准直器SPECT系统可改善病变 平面核素扫描和常规核素扫描的可探测性 SPECT(即需要大半径的水平旋转轴装置 旋转)。此外，还假设VAOR SPECT在用于 与图像重建算法相结合，补偿 衰减、检测到的康普顿散射事件和准直器分辨率为 能够检测到直径小于8毫米的小乳腺癌和 肿瘤与本底活性浓度比小于6：1。 与传统的SPECT系统相比，其主要优势是 建议的设计是：i)包括一个乳房的最小旋转半径 单独在视场中，二)提高系统灵敏度和分辨率 由于使用了多个摄像头和会聚光束或针孔 专门为乳房成像设计的准直器，III)减少衰减 对于从乳房发射的光子，iv)较少的覆盖和底层 如果存在心肌炎，则摄像机视野内的躯干活动 成像药物被使用，v)可倾斜相机提供了 将成像区域扩展到包括近胸壁组织的灵活性 几乎没有摄像病人的干扰。我们建议对这些问题进行调查 通过评估替代系统配置的假设，推导 首选系统配置的重建算法，评估 通过传导接收器工作特性来检测病变 研究，并将VAOR SPECT与平面核素扫描和 常规水平旋转轴SPECT。这样做的具体目的是 建议是：i)设计VAOR采集系统配置 乳腺癌成像，II)开发新的图像重建算法 对于选定的配置，以及iii)评估选定的配置和 图像重建算法。尽管建立VAOR SPECT系统是 除了这一初始提议的范围外，临床适用性将是 使用可倾斜的水平旋转轴SPECT设备进行演示 探测器用作初始VAOR可行性扫描的测试设施。

DESCRIPTION (Adapted from Applicant's Abstract): The long term goal of this research project is to develop new single photon emission computed tomography (SPECT) system designs for improved imaging and characterization of Tc-99m radiopharmaceutical uptake in early-stage breast cancer. The concepts being considered have multiple tiltable cameras, equipped with convergent beam or pinhole collimators, revolving around a single breast, with the patient in a prone position, aligned with the camera's vertical axis of rotation (VAOR). The main hypothesis is that a multiple-camera VAOR SPECT system with convergent beam collimators can improve lesion detectability over planar scintimammography, as well as over conventional SPECT (i.e., horizontal axis of rotation devices requiring a large radius of rotation). Also, it is hypothesized that VAOR SPECT, when used in conjunction with image reconstruction algorithms which compensate for attenuation, detected Compton scatter events and collimator resolution, is capable of detecting small breast cancers less than 8 mm in diameter and with a tumor-to-background activity concentration ratio less than 6 to 1. Compared with conventional SPECT systems, the primary advantages of the proposed design are: i) minimal radius of rotation by including one breast alone in the field-of-view, ii) improved system sensitivity and resolution due to the use of multiple cameras and convergent beam or pinhole collimators specially designed for breast imaging, iii) reduced attenuation for the photons emitted from the breast, iv) less overlying and underlying torso activities in the camera's field-of-view if existing myocardial imaging pharmaceuticals are used, and v) tiltable cameras provide a flexibility to extend the imaged region to include near-chest-wall tissue with little camera-patient interference. We propose to investigate these hypotheses by evaluating alternative system configurations, deriving reconstruction algorithms for preferred system configurations, evaluating lesion detectability by conducting receiver operating characteristics studies, and comparing VAOR SPECT with planar scintimammography and conventional horizontal axis of rotation SPECT. The specific aims of this proposal are: i) designing VAOR acquisition system configurations for breast cancer imaging, ii) developing new image reconstruction algorithms for selected configurations, and iii) evaluating selected configurations and image reconstruction algorithms. Although building a VAOR SPECT system is beyond the scope of this initial proposal, clinical applicability will be demonstrated using a horizontal axis of rotation SPECT device with tiltable detectors to serve as a test facility for initial VAOR feasibility scans.