Noninvasive thermometry using hyperfine-shifted MR signals from paramagnetic lanthanide complexes
Noninvasive thermometry using hyperfine-shifted MR signals from paramagnetic lanthanide complexes
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DOI：
10.1080/02656730500133801
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发表时间：
2005-09-01
影响因子：
3.1
通讯作者：
Bansal, N
中科院分区：
文献类型：
--
作者：
Hekmatyar, SK;Kerkhoff, RM;Bansal, N
基于强水H-1信号的MR温度测量技术提供了高的空间和时间分辨率，并已显示出应用前景，如激光手术和RF消融。然而，这些技术对于热疗应用具有低的温度敏感性，并且受局部运动和磁化率变化的影响很大。从顺磁性镧系元素配合物的Pr 3+，Yb 3+和Tm 3+的H-1 NMR信号显示高达300倍强的温度依赖性相比，水的H-1信号。此外，许多这些复合物的H-1化学位移对其他因素不敏感，例如顺磁性复合物的浓度、pH、[Ca 2 +]以及血浆大分子和离子的存在。镧系元素配合物在完整动物体温测量中的应用以及在幻影中绘制温度图的可行性已经得到证明。在迄今为止所研究的所有镧系元素配合物中，铥1，4，7，10-四甲基-1，4，7，10-四氮杂环十二烷-1，4，7，10-四乙酸酯（TmDOTMA（-））似乎是最有吸引力的用于体内MR测温的配合物。来自该络合物上的甲基的H-1信号由于12个当量质子而相对强烈，并且由于由铥诱导的大的顺磁位移而提供高的温度灵敏度。最近已经证明了在生理安全浓度下在完整动物中成像TmDOTMA（2）-的可能性。总体而言，基于顺磁性镧系元素复合物的超精细移位MR信号的MR测温方法似乎有希望用于动物应用，但在临床使用之前，需要进一步研究可接受的剂量和信噪比。
MR thermometry techniques based on the strong water H-1 signal provide high spatial and temporal resolution and have shown promise for applications such as laser surgery and RF ablation. However, these techniques have low temperature sensitivity for hyperthermia applications and are greatly influenced by local motion and susceptibility variations. H-1 NMR signals from paramagnetic lanthanide complexes of Pr3+, Yb3+ and Tm3+ show up to 300-fold stronger temperature dependence compared to the water H-1 signal. In addition, H-1 chemical shifts of many of these complexes are insensitive to other factors such as the concentration of the paramagnetic complex, pH, [Ca2+], and the presence of plasma macro-molecules and ions. Applications of lanthanide complexes for temperature measurement in intact animals and the feasibility of mapping temperatures in phantoms have been demonstrated. Among all the lanthanide complexes examined so far, thulium 1, 4, 7, 10-tetramethyl-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetate (TmDOTMA(-)) appears to be the most attractive for in vivo MR thermometry. The H-1 signal from the methyl groups on this complex is relatively intense because of 12 equivalent protons and provides high temperature sensitivity because of the large paramagnetic shifts induced by thulium. The possibility of imaging TmDOTMA(2)-in intact animals at physiologically safe concentrations has recently been demonstrated. Overall, MR thermometry methods based on hyperfine-shifted MR signals from paramagnetic lanthanide complexes appear promising for animal applications, but further studies relating to acceptable dose and signal-to-noise ratio are necessary before clinical use.