DYNAMIC CARDIAC SPECT IMAGING

单光子发射计算机断层扫描（SPECT）已成为一种重要的 诊断心脏病的工具，主要是因为它有 在评价心肌缺血方面具有重要的临床作用 以及最近用于评估心肌存活性。在过去 几年来，（201）Tl一直是主要的放射性药物，用于 心脏SPECT。最近，像塞斯塔米比和替泊肟这样的药物 用（99 m）Tc标记的放射性核素已被开发出来以取代（201）Tl。的 同位素（99 m）Tc比（201）Tl更理想，因为它具有更好的光子 能量和辐射吸收剂量特性。然而，这些代理人 未完全取代（201）Tl，部分原因是其生理 特色特别地，替硼肟具有快速的洗入和洗出特性， 这需要快速的断层摄影采集， 以前是不可行的。然而，随着多方面的发展， 探测器SPECT系统，我们已经证明，动态心脏SPECT 替硼肟的成像是可能的。动态心脏的发展 SPECT有可能提供比SPECT更敏感的缺血测量方法。 本发明的静态SPECT技术使用（201）Tl. 该提案的目标是规定动态的临床协议 能够获得完整投影的心脏SPECT成像 每5-10秒设置一个完整的三维组织分布， 短生物半衰期放射性药物， 数学工具从动态获取的数据中提取三个- 左侧动力学参数的空间分布 心室心肌组织血容量分数和洗入（k21） 和洗脱（k12）速率常数。该提案将开发适用于 数学工具，以准确和精确地量化动力学参数 并通过计算机模拟系统地评估这些方法， 犬实验和临床研究。完成后 还将指定提案设备要求。 该建议借鉴了PET中的生理建模发展。在 目前，PET在利用动态成像方面比SPECT先进得多， 成像以提取器官系统的动力学参数。其目的在于 该提案旨在开发能够使用现有方法的方法， 多探测器SPECT系统;并且，在这样做时，提供改善的健康 通过更好的心肌可检测性为公众提供护理 梗死，更好地诊断缺血性心脏病， 在不增加SPECT额外成本的情况下评估组织活力 procedure.开发的许多方法也将适用于其他 器官系统，如肾脏和大脑。

Single photon emission computed tomography (SPECT) has become an important tool in the diagnosis of heart disease, primarily because it has demonstrated an important clinical role in evaluating myocardial ischemia and more recently in evaluating myocardial viability. Over the last several years, (201)Tl has been the primary radiopharmaceutical used for cardiac SPECT. More recently, agents like sestamibi and teboroxime labelled with (99m)Tc have been developed to replace (201)Tl. The isotope(99m)Tc is more desirable than (201)Tl because of its better photon energy and radiation absorbed dose properties. However, these agents have not totally replaced (201)Tl due in part to their physiological characteristics. In particular, teboroxime has a fast wash-in and wash-out from the heart which requires rapid tomographic acquisitions which previously has not been feasible. However, with the advancement of multi- detector SPECT systems, we have demonstrated that dynamic cardiac SPECT imaging of teboroxime is possible. The development of dynamic cardiac SPECT has the potential to offer a more sensitive measure of ischemia than the present static SPECT techniques using (201)Tl. The goal of this proposal is to prescribe clinical protocols for dynamic SPECT imaging of the heart that are able to acquire complete projection sets every 5-10 seconds of a full three-dimensional tissue distribution of a short biological half-life radiopharmaceutical and to develop mathematical tools to extract from the dynamically acquired data a three- dimensional spatial distribution of kinetic parameters in the left ventricular myocardial tissue of blood volume fraction and wash-in (k21) and wash-out (k12) rate constants. The proposal will develop the applied mathematical tools to accurately and precisely quantify kinetic parameters and systematically evaluate these methods with computer simulations, canine experiments and clinical studies. At the completion of this proposal equipment requirements will also be specified. This proposal draws upon the physiological modeling development in PET. At present, PET is much further advanced than SPECT in utilizing dynamic imaging to extract kinetic parameters of organ systems. It is the intent of this proposal to develop methods that would be able to use existing multi-detector SPECT systems; and, in so doing, to provide improved health care to the general public through better detectability of myocardial infarcts, better diagnosis of ischemic heart disease, and better evaluation of tissue viability without adding additional cost to the SPECT procedure. Many of the methods developed will also be applicable to other organ systems such as the kidney and the brain.