Van den Berg Cornelis A T, Van de Kamer Jeroen B, De Leeuw Astrid A C, Jeukens Cécile R L P N, Raaymakers Bas W, van Vulpen Marco, Lagendijk Jan J W
Department of Radiotherapy, University Medical Center Utrecht, PO Box 85500, HP Q.00.118 3508 GA Utrecht, The Netherlands.
Phys Med Biol. 2006 Feb 21;51(4):809-25. doi: 10.1088/0031-9155/51/4/004. Epub 2006 Jan 25.
The application of thermal modelling for hyperthermia and thermal ablation is severely hampered by lack of information about perfusion and vasculature. However, recently, with the advent of sophisticated angiography and dynamic contrast enhanced (DCE) imaging techniques, it has become possible to image small vessels and blood perfusion bringing the ultimate goal of patient specific thermal modelling closer within reach. In this study dynamic contrast enhanced multi-slice CT imaging techniques are employed to investigate the feasibility of this concept for regional hyperthermia treatment of the prostate. The results are retrospectively compared with clinical thermometry data of a patient group from an earlier trial. Furthermore, the role of the prostate vasculature in the establishment of the prostate temperature distribution is studied. Quantitative 3D perfusion maps of the prostate were constructed for five patients using a distributed-parameter tracer kinetics model to analyse dynamic CT data. CT angiography was applied to construct a discrete vessel model of the pelvis. Additionally, a discrete vessel model of the prostate vasculature was constructed of a prostate taken from a human corpse. Three thermal modelling schemes with increasing inclusion of the patient specific physiological information were used to simulate the temperature distribution of the prostate during regional hyperthermia. Prostate perfusion was found to be heterogeneous and T3 prostate carcinomas are often characterized by a strongly elevated tumour perfusion (up to 70-80 ml 100 g(-1) min(-1)). This elevated tumour perfusion leads to 1-2 degrees C lower tumour temperatures than thermal simulations based on a homogeneous prostate perfusion. Furthermore, the comparison has shown that the simulations with the measured perfusion maps result in consistently lower prostate temperatures than clinically achieved. The simulations with the discrete vessel model indicate that significant pre-heating takes place in the prostate capsule vasculature which forms a possible explanation for the discrepancy. Pre-heating in the larger pelvic vessels is very moderate, approximately 0.1-0.3 degrees C. In conclusion, perfusion imaging provides important input for thermal modelling and can be used to obtain a lower limit on the prostate and tumour temperature in regional hyperthermia. However, it is not sufficient to calculate in detail the prostate temperature distribution in individual patients. The prostate vasculature plays such a crucial role that a patient specific discrete vessel model of the prostate vasculature is required.
由于缺乏有关灌注和脉管系统的信息，热模型在热疗和热消融中的应用受到严重阻碍。然而，最近随着先进的血管造影和动态对比增强（DCE）成像技术的出现，对小血管和血液灌注进行成像已成为可能，从而使针对患者的热模型这一最终目标更近在咫尺。在本研究中，采用动态对比增强多层CT成像技术来研究这一概念用于前列腺区域热疗的可行性。将结果与来自早期试验的患者组的临床温度测量数据进行回顾性比较。此外，研究了前列腺脉管系统在前列腺温度分布形成中的作用。使用分布式参数示踪动力学模型为五名患者构建了前列腺的定量三维灌注图，以分析动态CT数据。应用CT血管造影构建骨盆的离散血管模型。此外，从一具人类尸体获取的前列腺构建了前列腺脉管系统的离散血管模型。使用三种逐渐纳入患者特定生理信息的热模型方案来模拟区域热疗期间前列腺的温度分布。发现前列腺灌注是不均匀的，T3期前列腺癌通常具有肿瘤灌注显著升高的特征（高达70 - 80 ml 100 g⁻¹ min⁻¹）。与基于均匀前列腺灌注的热模拟相比，这种升高的肿瘤灌注导致肿瘤温度低1 - 2摄氏度。此外，比较表明，使用测量的灌注图进行的模拟导致的前列腺温度始终低于临床实际温度。使用离散血管模型进行的模拟表明，在前列腺包膜脉管系统中发生了显著的预热，这可能是差异的一个解释。较大盆腔血管中的预热非常轻微，约为0.1 - 0.3摄氏度。总之，灌注成像为热模型提供了重要输入，可用于获得区域热疗中前列腺和肿瘤温度的下限。然而，要详细计算个体患者的前列腺温度分布是不够的。前列腺脉管系统起着至关重要的作用，因此需要针对患者的前列腺脉管系统离散血管模型。
