Schwarzmaier H J, Yaroslavsky I V, Yaroslavsky A N, Fiedler V, Ulrich F, Kahn T
German National Research Center for Information Technology, St. Augustin, Germany.
J Magn Reson Imaging. 1998 Jan-Feb;8(1):121-7. doi: 10.1002/jmri.1880080124.
MR techniques have been demonstrated to allow a reliable monitoring of laser-induced interstitial thermotherapy (LITT). However, an adequate on-line control of this coagulation technique requires an exact therapy planning. The latter is mandatory to interpret the MR-monitoring data correctly to guarantee a precise laser irradiation. Moreover, it is a prerequisite for on-line decisions if modifications of the therapeutic regimen are required. In this work, we present a new simulation technique for LITT planning. The model accounts for the specific geometry of the treatment site, the exact configuration of the applicator, and the optical and thermal properties of the tissue, including changes during the heating process. The simulation results were compared with MR scans of laser-induced lesions in three patients with World Health Organization (WHO) grade II astrocytoma. Special interest was directed toward the role of blood perfusion, which was studied parametrically. Good agreement between the simulation results and the MR data was found if the appropriate blood perfusion rates were taken into account. Thus, the model can generate valid therapy plans allowing a precise on-line control of laser irradiation using MR techniques. Neglecting adequate perfusion parameters resulted in substantial errors with respect to the prediction of the final laser lesion.
磁共振技术已被证明能够可靠地监测激光间质热疗（LITT）。然而，对这种凝固技术进行充分的在线控制需要精确的治疗计划。后者对于正确解读磁共振监测数据以确保精确的激光照射至关重要。此外，它是决定是否需要修改治疗方案的在线决策的先决条件。在这项工作中，我们提出了一种用于LITT计划的新模拟技术。该模型考虑了治疗部位的特定几何形状、施照器的精确配置以及组织的光学和热特性，包括加热过程中的变化。将模拟结果与三名世界卫生组织（WHO）二级星形细胞瘤患者激光诱导损伤的磁共振扫描结果进行了比较。特别关注了血液灌注的作用，并对其进行了参数研究。如果考虑适当的血液灌注率，模拟结果与磁共振数据之间有良好的一致性。因此，该模型可以生成有效的治疗计划，从而使用磁共振技术对激光照射进行精确的在线控制。忽略适当的灌注参数会导致在预测最终激光损伤方面出现重大误差。
