Isotopes for New Modalities of PET/SPECT Imaging: Experimentation and Evaluation

通过PET和SPECT的常规医学成像依赖于反投影技术，并且其具有由于伽马射线的散射和吸收而导致的伪影的缺点，从而导致假阴性和/或假阳性诊断。已经建议使用单独的同位素的双能量成像作为改善图像质量的可能手段。他们总是涉及额外的设备，更高的剂量和更长的曝光等，我们尝试了一种新的方法相结合的PET/SPECT成像与单一的同位素发射正电子和伽马射线在不到几纳秒的时间滞后。实现后，可以采用核物理和粒子物理实验中的标准三维顶点重建技术. 除了增强对比度之外，该方法还提供了基于不同软件切割的多个图像以及传统的反投影，以严格评估图像伪影并最大限度地减少错误诊断。在确定候选同位素时，我们关注同位素对人体的生物相容性、衰减校正的双重能量要求、经济可行性和易于生产、材料的稳定性等。候选同位素是43-Sc、73-Se、123-Sc、85-Y、77-Kr和75-Br，其中的元素已经在医学上使用和摄入。

The conventional medical imaging by PET and SPECT relies on back projection techniques and it has drawbacks of artifacts due to scattering and absorption of gamma rays, contributing to false negative and/or false positive diagnostics. Dual energy imaging with separate isotopes has been suggested as possible means of improving the image qualities. They invariably involve additional equipment, higher doses and longer exposures etc. We attempt a novel approach of combining PET/SPECT imaging with single isotopes which emit positrons and gamma rays within less than a few nano second time lags. When implemented, we can employ standard 3D- vertex reconstruction technique of nuclear and particle physics experiments. In addition to enhanced contrast, this method provides multiple images based on different software cuts with conventional back projection to evaluate the image artifacts critically and minimize false diagnostics. In identifying candidate isotopes, we focussed on biological compatibility of isotopes to humans, dual energy requirement for attenuation corrections, economic viability and ease of production, stability of materials etc. The candidate isotopes are 43-Sc, 73-Se, 123-Xe, 85-Y, 77-Kr and 75-Br, the elements of which are already in medical use and ingestion.