Nariai Tadashi, Ishiwata Kiichi, Kimura Yuichi, Inaji Motoki, Momose Toshiya, Yamamoto Tetsuya, Matsumura Akira, Ishii Kenji, Ohno Kikuo
Department of Neurosurgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japan.
Appl Radiat Isot. 2009 Jul;67(7-8 Suppl):S348-50. doi: 10.1016/j.apradiso.2009.03.061. Epub 2009 Mar 27.
To plan the optimal BNCT for patients with malignant cerebral glioma, estimation of the ratio of boron concentration in tumor tissue against that in the surrounding normal brain (T/N ratio of boron) is important. We report a positron emission tomography (PET) imaging method to estimate T/N ratio of tissue boron concentration based on pharmacokinetic analysis of amino acid probes.
Twelve patients with cerebral malignant glioma underwent 60 min dynamic PET scanning of brain after bolus injection of (18)F-borono-phenyl-alanine (FBPA) with timed arterial blood sampling. Using kinetic parameter obtained by this scan, T/N ratio of boron concentration elicited by one-hour constant infusion of BPA, as performed in BNCT, was simulated on Runge-Kutta algorithm. (11)C-methionine (MET) PET scan, which is commonly used in worldwide PET center as brain tumor imaging tool, was also performed on the same day to compare the image characteristics of FBPA and that of MET.
PET glioma images obtained with FBPA and MET are almost identical in all patients by visual inspection. Estimated T/N ratio of tissue boron concentration after one-hour constant infusion of BPA, T/N ratio of FBPA on static condition, and T/N ratio of MET on static condition showed significant linear correlation between each other.
T/N ratio of boron concentration that is obtained by constant infusion of BPA during BNCT can be estimated by FBPA PET scan. This ratio can also be estimated by MET-PET imaging. As MET-PET study is available in many clinical PET center, selection of candidates for BNCT may be possible by MET-PET images. Accurate planning of BNCT may be performed by static images of FBPA PET. Use of PET imaging with amino acid probes may contribute very much to establish an appropriate application of BNCT for patients with malignant glioma.
为了为恶性脑胶质瘤患者规划最佳的硼中子俘获疗法（BNCT），估算肿瘤组织中硼浓度与周围正常脑组织中硼浓度的比值（硼的T/N比值）非常重要。我们报告了一种基于氨基酸探针药代动力学分析来估算组织硼浓度T/N比值的正电子发射断层扫描（PET）成像方法。
12例脑恶性胶质瘤患者在静脉推注（18）F-硼代苯丙氨酸（FBPA）后进行了60分钟的脑部动态PET扫描，并定时采集动脉血样。利用此次扫描获得的动力学参数，在龙格-库塔算法上模拟了BNCT中通过一小时持续输注BPA引发的硼浓度T/N比值。同一天还进行了（11）C-蛋氨酸（MET）PET扫描，这是全球PET中心常用的脑肿瘤成像工具，以比较FBPA和MET的图像特征。
通过视觉检查，所有患者用FBPA和MET获得的PET胶质瘤图像几乎相同。一小时持续输注BPA后估算的组织硼浓度T/N比值、静态条件下FBPA的T/N比值以及静态条件下MET的T/N比值之间显示出显著的线性相关性。
BNCT期间通过持续输注BPA获得的硼浓度T/N比值可通过FBPA PET扫描估算。该比值也可通过MET-PET成像估算。由于许多临床PET中心都可进行MET-PET研究，因此通过MET-PET图像有可能筛选出BNCT的候选患者。通过FBPA PET的静态图像可准确规划BNCT。使用氨基酸探针的PET成像可能对为恶性胶质瘤患者建立合适的BNCT应用有很大帮助。
