Feasibility of Multipinhole SPECT for Prostate Imaging

描述(由申请人提供)：准确和及时的前列腺癌(PCA)分期对于匹配患者与适当的治疗至关重要。仅使用解剖成像的非侵入性分期技术是不够的，广泛的研究工作集中在利用PCa体内机制的分子成像试剂上。SPECT在前列腺癌的分子成像方面有相当大的潜力。目前正在使用的一种SPECT试剂是ProstaScint，这是一种In-111放射性标记的单抗，用于检测骨盆和腹部淋巴结中的软组织前列腺癌转移。ProstaScint已获得FDA的批准，用于评估新诊断的病例以及有复发风险的已治疗患者，但ProstaScint扫描的解释具有足够的挑战性，以至于很少有机构提供成像测试。ProstaScint成像临床方案的固有缺陷导致了这一问题。标准SPECT系统配备旋转摄像头和中能平行孔(MEPAR)准直器来控制In-111伽马射线的间隔穿透，提供相对较差的光子灵敏度和空间分辨率。我们假设，MEPAR SPECT的实用替代品可以显著改善ProstaScint成像。最近，专门用于心脏成像的新型多针孔(MPH)系统显示出令人印象深刻的结果，超过了平行孔准直的空间分辨率和检测效率。这项建议的目的是研究MPH SPECT在PCa成像中的应用。在模拟工作中，我们将应用基于任务的技术评估范式来评估诊断性能。我们的目标之一是设计和优化一种专门用于前列腺成像的新型MPH系统。这项建议的具体目标是：1)实施模拟临床上真实的PCa图像集的程序；2)优化MPH SPECT成像PCA的设计；以及3)比较MPH和MEPAR SPECT诊断前列腺癌的图像。我们方法的一个独特元素是利用数字观察者来模仿人类观察者执行感兴趣的临床现实任务，提供了在广泛的临床相关任务中对人类表现进行准确预测的可能性。我们的长期目标是改善前列腺癌的SPECT成像。预计这样的改进不仅对ProstaScint有帮助，而且对未来可能引入临床的前列腺特异性SPECT试剂也有帮助。总体而言，项目目标的完成可以转化为改善PCA的分期和更有效的管理，降低患者风险并增强对治疗的反应。 公共卫生相关性：对前列腺癌在体内的进展进行准确的分期对于疾病的适当管理至关重要，但目前的分期方法是不够的。这笔赠款将研究新的单光子发射断层扫描(SPECT)相机设计，以通过非侵入性成像改进分期。这项研究的潜在好处包括更好地识别将从特定治疗中受益的患者，改善对治疗的反应，以及对前列腺癌的成本效益诊断和治疗。

DESCRIPTION (provided by applicant): Accurate and timely staging of prostate cancer (PCa) is essential for matching patients with the appropriate treatment. Noninvasive staging techniques using anatomical imaging alone are inadequate and extensive research efforts have focused on molecular imaging agents that exploit the in-vivo mechanisms of PCa. There is considerable potential for SPECT for molecular imaging of the prostate. One SPECT agent now in use is ProstaScint, an In-111-radiolabeled monoclonal antibody for detecting soft-tissue PCa metastases in the lymph nodes of the pelvis and abdomen. ProstaScint has FDA approval for the evaluation of newly diagnosed cases as well as treated patients who are at risk of recurrence, but interpretation of ProstaScint scans is challenging enough that few institutions offer the imaging test. Inherent weaknesses with the clinical protocol for ProstaScint imaging contribute to this problem. The standard SPECT systems with rotating camera heads and medium-energy parallel-hole (MEPAR) collimators to control septal penetration of the In-111 gamma rays deliver relatively poor photon sensitivity and spatial resolution. We hypothesize that practical alternatives to MEPAR SPECT are available to significantly improve ProstaScint imaging. Novel multipinhole (MPH) systems dedicated to cardiac imaging have recently shown impressive results surpassing the spatial resolu- tion and detection efficiency of parallel-hole collimation. The goal of this proposal is to investigate the utility of MPH SPECT for imaging PCa. Working in simulation, we shall apply the paradigm of task-based technology assessment to evaluate diagnostic performances. Among our objectives is the design and optimization of a novel MPH system dedicated to prostate imaging. The specific aims of this proposal are: 1) implemention of procedures for simulating sets of clinically realistic PCa images; 2) optimization of MPH SPECT designs for imaging PCa; and 3) comparison of MPH and MEPAR SPECT for diagnostic prostate imaging. A unique element of our approach is the utilization of numerical observers intended to mimic human observers for clinically realistic tasks of interest, offering the potential for accurate predictions of human performance over a wide array of clinically relevant tasks. Our long-term objective is to improve SPECT imaging of PCa. It is expected that such improvements would help not only with ProstaScint but also with future prostate-specific SPECT agents that may be introduced into the clinic. Overall, completion of the project aims could translate to improved staging and more effective management of PCa, reducing patient risks and enhancing response to therapy. PUBLIC HEALTH RELEVANCE: Accurate staging of the progression of prostate cancer in the body is vital for proper management of the disease, but current staging methods are inadequate. This grant will investigate new single photon emission tomography (SPECT) camera designs for improved staging via noninvasive imaging. Among the potential benefits of this study are better identification of patients who would benefit from a particular therapy, improved response to therapy and cost-effective diagnosis and treatment of prostate cancer.