IMPROVED QUANTITATIVE GA-65 SPECT IMAGING

描述(改编自申请人摘要)：建议的目标 研究是为了改进获取、重建和提取 来自Ga-67 SPECT数据的定量信息，并对这些信息进行评估 使用任务相关标准对成像系统进行改进。镓 已被证明是一种有用的核医学示踪剂 肿瘤，已知镓的亲和力与 组织病理学肿瘤分级。然而，成像Ga-67是具有挑战性的，因为 它会发出许多高能光子。Ga-67肿瘤的定量估计 吸收能力因三个主要误差来源而降低：a 光子散射不完全校正引起的位置相关偏差 和非均匀衰减，这是一种大小相关的偏差，由 非平稳探测器响应函数和产生的随机变异性 从采集的数据中的泊松噪声。拟议的研究将解决 这些挑战通过(1)优化Ga-67成像的几种方法来实现 校正患者体内的散射和衰减的影响的图像， (2)对已开发的Ga-67 SPECT方法进行修改 用于使用先验边界估计感兴趣体积内的活动 来自配准CT图像的信息，以及(3)设计新的准直器， 为人体成像中的Ga-67定量量身定做。的这些方面 将根据性能对成像系统进行优化和评估 在几个定量成像任务中。要考虑的任务， 胸部和腹部肿瘤量化的原型，将涉及 估计位于以下区域的病变的活动浓度和大小 解剖上逼真的背景。对于其中的每一项任务，Cramer-Rao 将计算方差或均方误差的下限以确定 不同校正方法的最佳性能，同时 将使用最大似然或贝叶斯参数估计来测量 最佳实现性能。感兴趣的活动数量估计 分辨率恢复将用于评估临床可实现性 性能。调查人员将通过模拟和体模来测量 实验，在这些任务中的性能改进，并比较 结果与性能的理论界限。他们还将考虑 S非霍奇金淋巴瘤相关临床分型任务。它是 预计拟议的成像系统改进将带来更多 淋巴瘤患者的准确分期，从而改善患者 护理由于增强了跟踪疾病进展的能力，选择 最好的治疗，并监测治疗的反应。

DESCRIPTION (Adapted from Applicant's Abstract): The goal of the proposed research is to improve the acquisition, reconstruction, and extraction of quantitative information from Ga-67 SPECT data, and to assess these improvements to the imaging system using task-dependent criteria. Gallium has proven to be a useful nuclear medicine tracer for imaging certain tumors, and it is known that gallium avidity is correlated with histopathologic tumor grade. Imaging Ga-67, however, is challenging because it emits many high-energy photons. Quantitative estimates of Ga-67 tumor uptake are degraded by three principal sources of error: a location-dependent bias caused by imperfect correction for photon scatter and nonuniform attenuation, a size-dependent bias due to blurring by the nonstationary detector response function, and stochastic variability arising from Poisson noise in the acquired data. The proposed research will address these challenges by (1) optimizing for Ga-67 imaging several methods of correcting images for the effects of scatter and attenuation in the patient, (2) modifying for Ga-67 SPECT methods that have previously been developed for estimating activity within volumes of interest using a priori boundary information from registered CT images, and (3) designing a new collimator, tailored for Ga-67 quantitation in body imaging. These aspects of the imaging system will be optimized and evaluated on the basis of performance in several quantitative imaging tasks. The tasks to be considered, prototypes of tumor quantitation in the chest and abdomen, will involve estimation of activity concentration and size of lesions located in anatomically realistic backgrounds. For each of these tasks, Cramer-Rao lower bounds on variance or mean-squared error will be computed to determine the best possible performance for different correction methods, while maximum-likelihood or Bayesian parameter estimation will be used to measure best realized performance. Volume-of-interest activity estimation with resolution recovery will be used to assess clinically realizable performance. The investigators will measure, by simulation and phantom experiment, the improvements in performance in these tasks, and compare the results with theoretical bounds on performance. They will also consider clinical classification tasks related to non-Hodgkin s lymphoma. It is expect that the proposed imaging system improvements will lead to more accurate staging of lymphoma patients and, consequently, improved patient care due to enhanced capability to follow the progression of disease, choose the best treatment, and monitor the response to therapy.