Kaplan E, Mayron L W, Friedman A M, Gindler J E, Frazin L, Moran J M, Loeb H, GUNNAR R M
Am J Cardiol. 1976 May;37(6):878-84. doi: 10.1016/0002-9149(76)90113-2.
Krypton-81m, a radionuclide emitting a 190 kev gamma ray, has a half-life of 13 seconds. It is a radioisotope of an inert water-soluble noble gas and is produced at a constant rate by spontaneous decay of rubidium-81 in an 81Rb-81mKr generator-delivery system. Delivery is through a minibore Teflon catheter that can be threaded through a standard no. 7 or 8F angiographic catheter. The generator is eluted by 5 percent dextrose-in-water, delivered by infusion pump at 1.5 ml/min, and the eluate is infused intraarterially directly into any organ. Delivery and decay reach equilibrium within 2 minutes, producing a heterogeneous distribution that is proportional to the perfusibility of the tissue concerned and the time required to reach it. The ultrashort halflife of the radionuclide rapidly eliminates activity when delivery ceases; thus, experiments can be sequentially repeated at brief intervals. The radiation hazard for easily imaged doses is negligible. Preliminary studies in open chest dogs were visualized by scintillation camera, stored on digital data disk, processed, and displayed in dual channel, dual color mode on a video system. Images of myocardial perfusion defined relative levels of perfusion, collateral circulation between coronary arterial branches, equilibrium time of diffusible perfusion of the myocardium, focal defects in induced occlusion, collateral circulation to occlusion, and reactive hyperemia after release of induced coronary occlusion. The system and technique appear applicable to human subjects.
氪-81m是一种发射190千电子伏特γ射线的放射性核素，半衰期为13秒。它是一种惰性水溶性稀有气体的放射性同位素，在81Rb-81mKr发生器输送系统中由铷-81的自发衰变以恒定速率产生。通过一根可穿过标准7号或8F血管造影导管的微管聚四氟乙烯导管进行输送。发生器用5%的葡萄糖水溶液洗脱，由输液泵以1.5毫升/分钟的速度输送，洗脱液经动脉直接注入任何器官。输送和衰变在2分钟内达到平衡，产生一种与相关组织的灌注能力和达到该状态所需时间成比例的不均匀分布。当输送停止时，放射性核素的超短半衰期会迅速消除活性；因此，可以在短时间间隔内依次重复进行实验。对于易于成像的剂量，辐射危害可忽略不计。对开胸犬的初步研究通过闪烁相机进行可视化，存储在数字数据盘上，进行处理，并在视频系统上以双通道、双色模式显示。心肌灌注图像可确定灌注的相对水平、冠状动脉分支之间的侧支循环、心肌可扩散灌注的平衡时间、诱导性闭塞中的局灶性缺损、闭塞的侧支循环以及诱导性冠状动脉闭塞解除后的反应性充血。该系统和技术似乎适用于人类受试者。
