PET pharmacokinetic analysis to estimate boron concentration in tumor and brain as a guide to plan BNCT for malignant cerebral glioma.
BACKGROUND
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Department of Neurosurgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japan. nariai.nsrg@tmd.ac.jp
Tadashi
T
Nariai
Kiichi
K
Ishiwata
Yuichi
Y
Kimura
Motoki
M
Inaji
Toshiya
T
Momose
Tetsuya
T
Yamamoto
Akira
A
Matsumura
Kenji
K
Ishii
Kikuo
K
Ohno
D000465:Algorithms; D001254:Astrocytoma / Q000000981:diagnostic imaging / Q000378:metabolism / Q000532:radiotherapy; D001895:Boron / Q000493:pharmacokinetics / Q000627:therapeutic use; D001896:Boron Compounds; D016754:Boron Neutron Capture Therapy / Q000379:methods* / Q000706:statistics & numerical data; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000532:radiotherapy*; D002250:Carbon Radioisotopes; D005909:Glioblastoma / Q000000981:diagnostic imaging / Q000378:metabolism / Q000532:radiotherapy; D005910:Glioma / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000532:radiotherapy*; D006801:Humans; D008715:Methionine; D010649:Phenylalanine / Q000031:analogs & derivatives; D049268:Positron-Emission Tomography / Q000379:methods*; D011838:Radiation-Sensitizing Agents / Q000493:pharmacokinetics / Q000627:therapeutic use; D011880:Radiotherapy Planning, Computer-Assisted / Q000706:statistics & numerical data
D001896:Boron Compounds; D002250:Carbon Radioisotopes; D011838:Radiation-Sensitizing Agents; C072915:4-borono-2-fluorophenylalanine; D010649:Phenylalanine; D008715:Methionine; D001895:Boron