Low cost detector for cardiac SPECT imaging

摘要 几十年来，心血管疾病一直是美国人的头号杀手。CVD也是我们的 全美最昂贵的慢性病。2014年，中风和心力衰竭是最昂贵的慢性病 在医疗保险按服务收费计划中。根据患病率、死亡率、残疾和费用，心血管疾病将 仍然是美国人在未来几十年将面临的最沉重的疾病。据估计，总共 与心血管疾病相关的成本超过5000亿美元[AHA]。尽管有其他方式可以用来诊断 对于心脏病，心肌SPECT仍然是评估心肌缺血的最佳诊断工具，因此 冠脉病变程度及预后。到目前为止，心肌SPECT扫描是美国最常见的程序 核医学系。由于这些原因，我们可以预期疗效的显著改善 心肌SPECT的应用将对患者的健康和医疗实践产生重大影响。许多限制 心肌SPECT显像的缺陷源于伽马相机的不足。 最近，新一代心脏SPECT相机已经被开发出来，它利用像素化 直接从相互作用的伽马射线中读出电信号的镉锌碲(CZT)探测器。这些相机 展示了比传统伽马更高的空间分辨率、探测效率和能量分辨率 摄像机。这第一代CZT心脏SPECT相机的初步结果似乎很有希望。 然而，CZT的问题可能会限制使用更大的CZT的另一代CZT相机的可能性 探测器和改进的性能。CZT晶体很难生长；好的CZT探测器很难 生产，产量低，因此，他们非常昂贵。 本申请提出从溴化铊(TlBr)开发成像探测器，该溴是一种稠密、高Z、 宽禁带半导体。与CZT相比，TlBr具有几个优点，包括显著降低熔化程度 点生长，室温下高电阻率，较高的Z和密度，因此需要较少的材料 获得给定的检测效率和更高的迁移率-孔洞寿命乘积，使有效正交化 条带探测器是可行的。RMD建议演示用于心脏SPECT成像的探测器模块 可以用于现有的心脏半导体探测器摄像机，这应该会提高它们的性能。 这些检测器模块将使用一种不同的读出技术，即正交条带检测，它可以减少 对于传统的像素化探测器，从n2读出n2个“像素”所需的电子通道数 2N.RMD的目标是开发TlBR作为心脏SPECT成像的CZT的更有效、更便宜的替代品。 在第一阶段中，制作了不同面积和条间距的TlBr正交条探测器，并 特色化的。论证了TlBR正交条探测器用于心脏SPECT的可行性。 在第二阶段，将开发出可与现有的CZT相比较的更大面积的成像模块 心脏SPECT扫描仪中的模块。

Abstract Cardiovascular disease (CVD) has been the leading killer of Americans for decades. CVD is also our nation’s costliest chronic disease. In 2014, stroke and heart failure were the most expensive chronic conditions in the Medicare fee-for-service program. Based on prevalence, death rates, disability and cost, CVD will continue to be the most burdensome disease Americans will face in the next decades. It is estimated that total costs related to CVD are more than $ 500 billion [AHA]. Although there are other modalities used to diagnose heart disease, myocardial SPECT remains the best diagnostic tool for assessing myocardial ischemia, and thus the extent of CAD and its prognosis. Myocardial SPECT scans are by far the most common procedures in US nuclear medicine departments. For these reasons, we can expect that significant improvements in the efficacy of myocardial SPECT will have major impacts on patient health and medical practice. Many of the limitations of myocardial SPECT imaging originate in deficiencies of the gamma camera. Recently, a new generation of cardiac SPECT cameras have been developed that make use of pixelated CdZnTe (CZT) detectors that directly read out electrical signals from interacting gamma rays. These cameras demonstrate improved spatial resolution, detection efficiency and energy resolution over conventional gamma cameras. The initial results from this first generation of CZT cardiac SPECT cameras seem promising. However, problems with CZT may limit the possibility of another CZT camera generation with larger CZT detectors and improved performance. CZT crystals are difficult to grow; good CZT detectors are difficult to produce, the yield is low, and they are consequently very expensive. This application proposes to develop imaging detectors from thallium bromide (TlBr), a dense, high Z, wide band gap semiconductor. TlBr has several advantages over CZT including significantly lower melting point, as-grown high resistivity at room temperature, higher Z and density so less material is required to achieve a given detection efficiency and higher mobility-lifetime product of holes making efficient orthogonal strip detectors feasible. RMD proposes to demonstrate detector modules for use in cardiac SPECT imaging that can be used in existing cardiac semiconductor detector cameras, and that should improve their performance. These detector modules will use a different readout technique, orthogonal strip detection that reduces the number of electronic channels required to read out N2 “pixels” from N2 for a conventional pixelated detector to 2N. RMD’s goal is to develop TlBr as a more efficient, less costly alternative to CZT for cardiac SPECT imaging. During Phase I TlBr orthogonal strip detectors with various areas and strip pitch were fabricated and characterized. The feasibility of utilizing TlBr orthogonal strip detectors for cardiac SPECT was demonstrated. During Phase II larger area imaging modules will be developed that can be compared with existing CZT based modules in cardiac SPECT scanners.