Royston D, Minty B D, Houston A, Jones J G, McLeod M
Br J Radiol. 1984 Mar;57(675):223-9. doi: 10.1259/0007-1285-57-675-223.
An aerosol of a radionuclide may be used for ventilation imaging as an alternative to radioactive rare gases. For good-quality images as few particles as possible must be deposited in the trachea and bronchi, which means that no, or very few, particles should have aerodynamic diameter of more than 2 micron. We have developed a separator to modify the output of an Acorn jet nebuliser. It reduced the proportion of particles in the aerosol with aerodynamic diameters of more than 2 micron from 60% for the unmodified output of the nebuliser to only 6%; it consisted of a cylinder of perspex with two compartments containing inert spheres, either stainless steel or glass, of diameter 3 mm (the first compartment contained two layers of spheres, and the main section was packed with spheres). To examine the efficiency of the separator system for routine clinical use we compared the images produced and the deposition of the particles in the modified aerosol (using 99TcmDTPA) with the distribution of ventilation of 81Krm in eight subjects. Despite the theoretical differences between the behaviour of a gas molecule and of a particle in the respiratory tree, the images produced using the modified aerosol delivery system were as good as those produced with 81Krm in normal subjects. In abnormal subjects the images produced were only distinguished following the calculation of a penetration index.
放射性核素气雾剂可用于通气成像，作为放射性稀有气体的替代物。为了获得高质量的图像，必须尽量减少沉积在气管和支气管中的颗粒数量，这意味着气溶胶中空气动力学直径大于2微米的颗粒应不存在或极少。我们开发了一种分离器来改变橡树果喷射雾化器的输出。它将气溶胶中空气动力学直径大于2微米的颗粒比例从雾化器未改装时输出的60%降低到仅6%；该分离器由一个有机玻璃圆筒组成，有两个隔室，里面装有直径为3毫米的惰性球体，即不锈钢或玻璃球体（第一个隔室有两层球体，主要部分装满了球体）。为了检验该分离系统用于常规临床的效率，我们比较了八名受试者使用改装后的气溶胶（使用99锝二乙三胺五醋酸）产生的图像及颗粒沉积情况与81氪通气分布情况。尽管气体分子和颗粒在呼吸树中的行为存在理论差异，但使用改装后的气溶胶输送系统产生的图像与正常受试者使用81氪产生的图像一样好。在异常受试者中，只有在计算穿透指数后才能区分所产生的图像。
