Reliable Human-Model Observers for Emission Tomography

描述（由申请人提供）：我们的总体目标是开发用于发射断层扫描可靠技术评估的数值观测者。正电子发射断层扫描（PET）和单光子发射断层扫描（SPECT）是许多类型癌症成像的主要临床方式。然而，早期发现通常是癌症存活的最佳机会，而这些成像方式对小肿瘤的诊断作用有限。系统的基于任务的发展评估可以促进早期识别有前途的新技术，以提高这些模式的诊断能力。然而，人类观察员的评估通常不适合用于发展。此外，可用的用于预测人类表现的数学模型（或数值观察者）——我们称之为人类模型观察者——存在显著的限制，包括可以考虑的诊断任务类型的约束。部分由于这些限制，现有的人体模型观察者经常需要在成像过程发生任何变化时重新验证。我们对观察员发展的方法是建立在任务等价的概念上的，即数值观察员的任务尽可能地反映了期望的临床任务。在这项授权中，我们提出了一个新的观察者框架，该框架受放射科医生视觉搜索（VS）过程描述的影响，其中图像的初始全局扫描确定值得仔细检查的候选位置。我们将使用VS范式来研究任务等价的假设，即i)可以导致一个可靠地推广到广泛的诊断任务的人类观察者模型，ii)是确保真正相关的基于任务的评估所必需的。我们将通过氟-18脱氧葡萄糖（FDG）全身PET和SPECT In-111神经内分泌肿瘤（NETs）成像的观察研究来检验这些假设。用于发展研究的最先进的模型观测者应该能够进行检测-定位任务，我们的观测者研究将使用jackknife FROC （JAFROC）方法进行分析。这项工作的具体目的是：1)确定FDG-PET图像切片的哪些特征吸引了最初的人类观察者的注意；2)开发用于FDG-PET肿瘤检测定位任务的VS数值观测器；3)在混合PET图像的JAFROC检测-定位研究中测试VS观察者与人类的对比；4)研究VS观察者对SPECT和3D检测定位任务的推广；5)比较从VS和现有数值观察者获得的肿瘤SPECT的系统优化。应用于In-111 . NET成像的平行孔准直器设计优化。

DESCRIPTION (provided by applicant): Our overall objective is to develop numerical observers for dependable technology evaluations in emission tomography. Positron emission tomography (PET) and single-photon emission tomography (SPECT) are the primary clinical modalities for imaging many types of cancer. However, early de- tection often presents the best chances of surviving cancer whereas these imaging modalities have limited diagnostic utility for small tumors. Systematic task-based developmental assessments could facilitate early identification of promising new technology for improving the diagnostic capabilities of these modalities. Yet, assessments with human observers are generally impractical for developmental use. Moreover, available mathematical models (or numerical observers) intended to predict human performance-what we refer to as human-model observers-present significant limits, including con- straints on the types of diagnostic tasks that can be considered. Partly because of these constraints, existing human-model observers frequently require revalidation given any change to the imaging pro- cess. Our approach to observer development is founded on the concept of task equivalence, whereby the task for the numerical observer mirrors the desired clinical task as closely as possible. In this grant, we propose a novel observer framework that is influenced by descriptions of radiologists' visual-search (VS) processes, in which an initial global scan of an image identifies candidate locations deserving closer inspection. We shall use the VS paradigm to investigate the hypotheses that task equivalence i) can lead to a human-observer model that reliably generalizes to a wide range of diagnostic tasks, and ii) is necessary to ensure truly relevant task-based evaluations. We shall test these hypotheses through observer studies with fluorine-18 deoxyglucose (FDG) whole-body PET and SPECT In-111 imaging of neuroendocrine tumors (NETs). A state-of-the-art model observer for developmental stud- ies should be capable of detection-localization tasks, and our observer studies will be analyzed with jackknife FROC (JAFROC) methodology. The specific aims of this work are to: 1) determine what features of FDG-PET image slices attract initial human-observer attention; 2) develop a VS numerical observer for tumor detection-localization tasks in FDG-PET; 3) test the VS observer against humans in a JAFROC detection-localization study featuring hybrid PET images; 4) investigate generalizations of the VS observer to SPECT and 3D detection-localization tasks; and 5) compare system optimiza- tions for oncologic SPECT obtained from the VS and existing numerical observers. The application is optimization of a parallel-hole collimator design for In-111 NET imaging. PUBLIC HEALTH RELEVANCE: Functional imaging with positron emission tomography (PET) and single-photon emission tomog- raphy (SPECT) has a significant role in cancer diagnosis and management. Still, early detection offers the best chances for surviving many cancers and refining the diagnostic capabilities of these modali- ties for small tumors continues to be a major research focus. This work is focused on the development of assessment methods for assisting in the early identification of technological advances that could improve the diagnostic utility of PET and SPECT.