Kalin B
Department of Diagnostic Radiology, Karolinska Hospital, Stockholm, Sweden.
Acta Radiol Suppl. 1993;385:1-24.
Today bone marrow scintigraphy is performed by imaging either the reticuloendothelial system by means of colloids or the hematopoietic marrow with granulocytes. When visualizing the marrow with radiolabeled colloids most of the administered activity will be taken up by the liver and spleen. To use granulocytes for bone marrow imaging is a comparatively expensive and complicated method. The aim of this study was to investigate the possibilities to shift the uptake of some of the injected activity from the liver-spleen and/or background to the bone marrow. Four small-sized colloids were evaluated in patients routinely referred for single photon emission computed tomography of the liver/spleen. After correction for attenuation and scattering of photons quantitative assessment of the activity in different organs was performed. Of the four colloids Nanocoll turned out to be the most favorable, thus this colloid was decided to be evaluated further. To assess the possibilities to improve the relative bone marrow uptake of Nanocoll, it was separated by gel filtration and different sized subfractions were injected into mice. None of the subfractions exhibited a more favorable bone marrow/liver-spleen ratio than the unseparated colloid. As blood clearance of a colloid is dependent on perfusion different measures were evaluated in mice aiming at either an increase in the blood flow to the bone marrow or a decrease in the liver-spleen perfusion. Nine different pharmaceuticals were tested. None improved the bone marrow uptake in relation to the liver enough to justify administration to humans. Fasting increased, however, the relative bone marrow uptake by approximately 15%. To evaluate the soft tissue background activity for colloids of different size a nanosized colloid (Nanocoll) and a larger colloid (Albu-Res) were investigated in an experimental mouse system and in humans. The latter were examined by quantitative single photon emission computed tomography as described above. The bone marrow activity relative to the soft tissue background activity was higher for the larger colloid in both mice and humans. By quantitative single photon emission computed tomography of the liver, spleen, bone marrow, and background the distribution of in vitro labeled autologous granulocytes and a colloid (Nanocoll) were assessed in patients. The activity of the bone marrow relative to the liver was significantly higher for granulocytes. The influence of scattered radiation is considerable in the vicinity of the liver. A technique for scatter correction with two opposing views was applied in a phantom and a human study. Both showed a considerable improvement of the visibility of the bone marrow close to the liver.(ABSTRACT TRUNCATED AT 400 WORDS)
如今，骨髓闪烁扫描术是通过使用胶体对网状内皮系统成像或使用粒细胞对造血骨髓成像来进行的。当用放射性标记的胶体对骨髓进行显像时，大部分注入的活性物质会被肝脏和脾脏摄取。使用粒细胞进行骨髓成像相对昂贵且复杂。本研究的目的是探讨将部分注入活性物质的摄取从肝脏 - 脾脏和/或背景转移至骨髓的可能性。在常规接受肝脏/脾脏单光子发射计算机断层扫描的患者中评估了四种小尺寸胶体。在校正光子的衰减和散射后，对不同器官中的活性物质进行了定量评估。在这四种胶体中，纳米胶体（Nanocoll）被证明是最有利的，因此决定对这种胶体进行进一步评估。为了评估提高纳米胶体相对骨髓摄取的可能性，通过凝胶过滤对其进行分离，并将不同大小的亚组分注入小鼠体内。没有一个亚组分表现出比未分离的胶体更有利的骨髓/肝脏 - 脾脏比值。由于胶体的血液清除取决于灌注，因此在小鼠中评估了旨在增加骨髓血流量或减少肝脏 - 脾脏灌注的不同措施。测试了九种不同的药物。但没有一种药物能使骨髓相对于肝脏的摄取增加到足以证明可用于人体给药的程度。然而，禁食使相对骨髓摄取增加了约15%。为了评估不同大小胶体的软组织本底活性，在实验小鼠系统和人体中研究了一种纳米尺寸的胶体（纳米胶体）和一种较大尺寸的胶体（白蛋白 - 瑞思）。后者如上述通过定量单光子发射计算机断层扫描进行检查。在小鼠和人体中，较大尺寸的胶体相对于软组织本底活性的骨髓活性更高。通过对肝脏、脾脏、骨髓和本底进行定量单光子发射计算机断层扫描，评估了患者体外标记的自体粒细胞和一种胶体（纳米胶体）的分布。粒细胞的骨髓相对于肝脏的活性明显更高。在肝脏附近，散射辐射的影响相当大。在模型和人体研究中应用了一种具有两个相对视图的散射校正技术。两者均显示肝脏附近骨髓的可见性有显著改善。（摘要截断于400字）
