Neutron Capture Therapy with Gd-DTPA in Tumor-Bearing Rats
Neutron Capture Therapy with Gd-DTPA in Tumor-Bearing Rats
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Gd-DTPA 对荷瘤大鼠的中子捕获疗法
DOI：
10.1007/978-1-4757-9567-7_123
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
R. Lawaczeck
中科院分区：
文献类型：
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作者：
V. Khokhlov;P. N. Yashkin;D. Silin;E. S. Djorova;R. Lawaczeck
Gd-DTPA二甲葡胺（Magnevist®）广泛用作磁共振成像（MRI）中的造影剂。它特别有助于描绘血脑屏障受损的脑肿瘤。二价阴离子[Gd-DTPA]2−扩散到肿瘤组织中，由于Gd 3+离子的大磁矩，导致水弛豫时间缩短，从而导致MRI信号强度变化2。许多耐受性良好的Gd络合物在临床上可用或正在临床开发中。除了其诊断价值外，天然丰度为15.7%的157 Gd还具有所有稳定同位素中热中子的最高横截面（255 000 barn（=10 - 24 cm 2））。天然Gd的平均横截面为48800 barn。中子俘获后，激发的Gd核通过发射能量高达7.9 MeV的光子和级联的转换和俄歇电子而弛豫。因此，Gd配合物已被建议作为中子捕获治疗（NCT）的试剂3- 6，并且Gd配合物的NCT效应已在体模中“在DNA水平上”进行了研究，并且在体外和体内系统中均进行了研究9 - 13。尽管关于瞬发γ或电子对治疗效果的贡献的讨论尚未解决，但已通过实验证明了细胞外Gd配合物的治疗增益9 - 13。在下文中，我们报告了用大鼠肿瘤模型和在用超热中子照射之前施用Gd-DTPA进行的实验。
Gd-DTPA dimeglumine (Magnevist®) is widely used as contrast medium in magnetic resonance imaging (MRI). It is especially helpful for the delineation of brain tumors with an injured blood-brain barrier’. The dianion [Gd-DTPA]2−diffuses into the tumorous tissue and due to the large magnetic moment of the Gd3+-ion leads to a shortening of the water relaxation times’ and, consequently, to changes of the MRI signal intensities2. A number of pharmacologically well-tolerated Gd-complexes are clinically available or under clinical development. In addition to its diagnostic value,157Gd with a natural abundance of 15.7% has the highest cross-section (255 000 barn (=10−24cm2)) for thermal neutrons of all stable isotopes. Natural Gd has an average cross-section of 48 800 barn. After neutron capture the excited Gd-nuclei relax via the emission of photons with energies up to 7.9 MeV and a cascade of conversion and Auger electrons. Therefore, Gd-complexes have been suggested as agents for neutron capture therapy (NCT)3–6and NCT effects of Gd-complexes have been studied in phantoms’, on the DNA level’, and in bothin vitroandin vivosystems9–13 Atherapeutic gain has been demonstrated experimentally for extracellular Gd-complexes9–13although the discussion on the contributions of prompt γ’s or electrons to the therapeutic effect is not yet settled. In the following we report on experiments performed with a rat tumor model and administration of Gd-DTPA prior to irradiation with epithermal neutrons.