Quantitative SPECT for Targeted Radionuclide Therapy

描述（由申请人提供）：近年来，SPECT成像取得了许多进展，包括重建和补偿方法以及成像系统的改进。然而，这项工作的大部分都是针对改进诊断程序。定量成像信息的收集是剂量测定和靶向放射性核素治疗（TRT）治疗计划的关键步骤。定量成像方法中的错误可导致疗效降低或不良副作用发生率增加。TRT剂量学最常用的定量方法是共轭视图平面成像，这是20多年前首创的方法。该项目的目标是开发，优化和评估，实用和临床可实施的定量成像方法，用于估计体内累积活性（即，随着时间的推移，在一个区域或器官中发生的放射性衰变的数量）。该方法将基于在SPECT/CT系统上执行的平面和一个或多个SPECT扫描的组合，并使用定量SPECT重建和平面处理技术进行处理。具体来说，考虑散射、衰减、部分体积效应、准直器穿透和散射的ln-111和1-131光子发射的SPECT重建算法将被开发。平面成像方法，包括横向和AP成像采集和基于SPECT扫描的器官重叠校正，将被检查以改善器官和肿瘤的描绘和放射性定量。蒙特卡罗模拟、物理幻影和患者数据将用于优化和验证方法。基于患者研究结果的数学模型将被开发并用于模拟各种解剖结构和药代动力学。将根据成像参数和采集技术对剂量学参数估计的影响来评估它们。定量成像是剂量学计算的关键输入，剂量学计算对TRT治疗计划至关重要。本提案中描述的工作将以实际和临床可实施的方式开发和验证改进定量的方法。如果成功，该项目将允许制定更准确的治疗计划，具有更大的治疗效果和更少的不良反应的潜力。它还将为试图了解TRT剂量-反应关系的临床研究提供有价值的方法改进。

DESCRIPTION (provided by applicant): In recent years there have been a number of advances in SPECT imaging including improvements in reconstruction and compensation methods, and imaging systems. However, much of this work has been targeted at improvement of diagnostic procedures. The collection of quantitative imaging information is a critical step in dosimetry and treatment planning for targeted radionuclide therapy (TRT). Errors in the quantitative imaging methods can result in reduced efficacy or increased incidence of adverse side effects. The most commonly used quantitation methodology for TRT dosimetry is conjugate-view planar imaging, a method pioneered more than 20 years ago. The goal of this project is to develop, optimize, and evaluate, practical and clinically implementable quantitative imaging methods for use in estimating in vivo the cumulated activity (i.e., the number of radioactive decays that occur in a region or organ integrated over time). The methods will be Dased on combinations of planar and one or more SPECT scans performed on a SPECT/CT system and processed using quantitative SPECT reconstruction and planar processing techniques. Specifically, SPECT reconstruction algorithms for ln-111 and 1-131 photon emissions that account for scatter, attenuation, partial volume effects, and collimator penetration and scatter will be developed. Planar imaging methods that incorporate lateral as well as AP imaging acquisition and organ overlap correction based on SPECT scans will be examined to improve organ and tumor delineation and radioactivity quantitation. Monte Carlo simulations, physical phantoms, and patient data will be used to optimize and validate the methodologies. A population of mathematical phantoms, based on the results of patient studies, will be developed and used to model various anatomies and pharmacokinetics. The imaging parameters and acquisition techniques will be evaluated in terms of their influence on the estimation of dosimetric parameters. Quantitative imaging is a critical input to dosimetry calculations that are essential to TRT treatment planning. The work described in this proposal will develop and validate methodologies for improving quantitation in a practical and clinically implementable manner. If successful, this project will allow the development of more accurate treatment plans with the potential for greater therapeutic effect and fewer adverse reactions. It will also provide valuable methodological improvements for clinical studies trying to understand TRT dose-response relationships.