O'Connor Michael K, Kemp Brad J
Department of Nuclear Medicine, Mayo Clinic, Rochester, MN 55905, USA.
Semin Nucl Med. 2006 Oct;36(4):258-66. doi: 10.1053/j.semnuclmed.2006.05.005.
Correlation of the anatomical and functional information presented by single-photon emission computed tomography (SPECT) and computed tomography (CT) can aid in the decision-making process by enabling better localization and definition of organs and lesions and improving the precision of surgical biopsies. Technical developments over the past 20 years have led to the development of better software techniques for image fusion and, more recently, to the development of modern SPECT/CT systems. While image fusion techniques have been in clinical use for many years, the first commercial SPECT/CT system was only developed in 1999. Following the commercial success of PET/CT systems that employed multidetector CT (MDCT) scanners, there has been renewed interest in the development of comparable SPECT/CT systems. This has resulted in the development of a range of SPECT/CT devices varying from a simple CT add-on to a conventional SPECT system that can provide low-dose CT images to a full MDCT scanner integrated with a SPECT system. The advantages of combining SPECT with CT are numerous and are primarily due to the anatomic referencing and the attenuation correction capabilities of CT. Depending on system design, there are varying technical issues surrounding the different SPECT/CT devices, ranging from cost, radiation dose, planning, and siting requirements to system-specific issues such as table sag and CT artifacts due to patient motion. Motion artifacts should be less prevalent with the faster acquisition times of modern scanners, but are still problematic in the thorax and have not yet been fully resolved as they pertain to the use of CT data for cardiac attenuation correction. As this technology matures, we can expect to see a range of SPECT/CT devices available on the market that range from low-dose 1-4 slice inexpensive CT upgrades of conventional SPECT systems, to SPECT systems incorporating 64 or 128 slices CT scanners. The cost of the high-end CT scanners will exceed the cost of the SPECT scanner and hence the justification for such devices will be heavily dependent on clear demonstration of their value in clinical practice.
单光子发射计算机断层扫描（SPECT）和计算机断层扫描（CT）所呈现的解剖学和功能信息之间的相关性，能够通过更好地定位和界定器官及病变，并提高手术活检的精确度，来辅助决策过程。过去20年的技术发展带来了更优的图像融合软件技术，最近还促成了现代SPECT/CT系统的发展。虽然图像融合技术已在临床应用多年，但首款商用SPECT/CT系统直到1999年才得以开发。继采用多排探测器CT（MDCT）扫描仪的PET/CT系统取得商业成功之后，人们对开发类似的SPECT/CT系统又重新产生了兴趣。这导致了一系列SPECT/CT设备的出现，从简单的CT附加装置到能提供低剂量CT图像的传统SPECT系统，再到与SPECT系统集成的全功能MDCT扫描仪。将SPECT与CT相结合的优势众多，主要得益于CT的解剖学参考和衰减校正能力。根据系统设计的不同，不同的SPECT/CT设备存在各种技术问题，从成本、辐射剂量、规划和选址要求到特定系统问题，如因患者移动导致的检查床下垂和CT伪影等。随着现代扫描仪采集时间的加快，运动伪影应该会不那么普遍，但在胸部仍然存在问题，而且就将CT数据用于心脏衰减校正而言，这些问题尚未得到完全解决。随着这项技术的成熟，我们有望在市场上看到一系列SPECT/CT设备，从传统SPECT系统的低剂量1 - 4层廉价CT升级设备，到集成了64层或128层CT扫描仪的SPECT系统。高端CT扫描仪的成本将超过SPECT扫描仪，因此此类设备的合理性将在很大程度上取决于其在临床实践中的价值能否得到明确证明。
