Low Dose Breast Computed Tomography with Photon Counting Detector

带光子计数探测器的低剂量乳房计算机断层扫描

• 批准号: 7678766
• 负责人: Huy Quang Le
• 金额: $ 3.99万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-03-24 至 2011-03-23
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7678766
• 关键词: Breast; Cancer Detection; Cancer Etiology; CdZnTe; Cessation of life; Charge; DCNU; Dose; Electronics; Electrons; Employee Strikes; Image; Malignant Neoplasms; Mammary Gland Parenchyma; Mammography; Medical Imaging; Noise; Patients; Photons; Property; Radiation; Signal Transduction; System; Translating; Woman; X-Ray Computed Tomography; absorption; base; breast scan; density; design; detector; imaging modality; improved; malignant breast neoplasm; prototype; public health relevance; quantum

DESCRIPTION (provided by applicant): The overall objective of the proposal is to develop and evaluate a photon counting and energy resolving breast computed tomography system. In every medical imaging modality, the aim is to generate the best image at the lowest dose possible. The tradeoff between image quality and patient dose is always an important consideration in designing a medical imaging system. In this study, we propose a breast CT system that has the capability of producing images of higher quality at a reduced dose compared to current breast CT systems. The key to the system involves a photon counting and energy resolving x-ray detector that is made of CdZnTe (CZT) crystals. Intrinsically, CZT has excellent energy absorption efficiency due to its large effective atomic number (49.6) and high mass density (5.8 g/cm3)-allowing for great radiation stopping power. Photon counting detectors allow for the recording of each x-ray photon and its energy as it is absorbed by the CZT. When a photon strikes the detector, electrons and holes are created and a current is produced by the propagation of electrons and holes. The amount of current produced is directly proportional to the energy of the photon. A threshold determines the current level at which a photon is counted. By setting an appropriate threshold, electronic and Swank noise can be completely rejected. Properties of low noise and high quantum efficiency translate to higher image signal-to-noise ratio (SNR) at a lower dose. The SNR of breast CT systems utilizing a photon counting detector can be improved by 30% as compared to those with a charge-integrating flat panel detector. An SNR improvement of 30% equals a dose reduction of 40% percent in breast CT. Our proposed CT system is expected to realize at least the same amount of dose reduction while improving cancer detection sensitivity by exploiting its energy resolving capability. The specific aims of this proposal are: 1) Construct a photon counting, slit-scanning breast computed tomography system using CZT detector for phantom and post-mortem studies, 2) Investigate the hypothesis that a CZT photon-counting CT system produces images of higher quality at a reduced dose, and 3) Evaluate the benefits afforded by the energy resolving capability of the detector. PUBLIC HEALTH RELEVANCE: Breast cancer is the fifth most common cause of cancer death-for women it is the leading cause of all cancer death, responsible for over half a million deaths worldwide. The sensitivity of mammography in detecting cancer is estimated to be 75-85%, and for dense breasts it is significantly lower. A photon-counting breast CT system has the potential to provide clinicians with images of high quality at a low dose, and therefore improve cancer detectability.

描述（由申请人提供）：该提案的总体目的是开发和评估光子计数和能量解决乳房计算机断层扫描系统。在每种医学成像方式中，目的是以最低剂量生成最佳图像。图像质量和患者剂量之间的权衡始终是设计医学成像系统的重要考虑因素。在这项研究中，我们提出了一个乳腺CT系统，该系统具有与当前乳腺CT系统相比，在降低剂量下质量更高的能力。该系统的关键涉及由CDZNTE（CZT）晶体制成的光子计数和能量解析X射线检测器。本质上，CZT由于其较大的有效原子数（49.6）和高质量密度（5.8 g/cm3）而具有出色的能量吸收效率 - 可用于大辐射停止功率。光子计数检测器允许记录每个X射线光子及其能量，因为它被CZT吸收。当光子撞击检测器时，会产生电子和孔，并通过电子和孔的传播产生电流。产生的电流量与光子的能量成正比。阈值确定计数光子的电流水平。通过设置适当的阈值，可以完全拒绝电子噪声和旋转噪声。低噪声和高量子效率的性能转化为较低剂量的较高图像信号噪声比（SNR）。与具有电荷整合平板检测器相比，利用光子计数检测器的乳腺CT系统的SNR可以提高30％。 30％的SNR改善等于乳房CT的剂量减少40％。我们提出的CT系统预计将至少实现相同数量的减少剂量，同时通过利用其能量解决能力来提高癌症检测敏感性。该提案的具体目的是：1）使用CZT检测器进行幻影和验尸研究，构建一个光子计数，开裂的乳房计算机层析成像系统，2）研究假设，即CZT光子计数CT系统可在降低的剂量下产生较高质量的图像，并且3）评估能量可辨别能力的能力。公共卫生相关性：乳腺癌是癌症死亡女性的第五大最常见原因，这是所有癌症死亡的主要原因，全世界造成超过半百万的死亡。乳腺X线摄影在癌症中的敏感性估计为75-85％，对于密集的乳房，它的敏感性明显降低。光子计数乳腺CT系统有可能在低剂量下为临床医生提供高质量的图像，从而改善癌症的可检测性。