PT  - JOURNAL ARTICLE
AU  - Michie Miyoshi
AU  - Hiroshi Ito
AU  - Ryosuke Arakawa
AU  - Hidehiko Takahashi
AU  - Harumasa Takano
AU  - Makoto Higuchi
AU  - Masaki Okumura
AU  - Tatsui Otsuka
AU  - Fumitoshi Kodaka
AU  - Mizuho Sekine
AU  - Takeshi Sasaki
AU  - Saori Fujie
AU  - Chie Seki
AU  - Jun Maeda
AU  - Ryuji Nakao
AU  - Ming-Rong Zhang
AU  - Toshimitsu Fukumura
AU  - Masayasu Matsumoto
AU  - Tetsuya Suhara
TI  - Quantitative Analysis of Peripheral Benzodiazepine Receptor in the Human Brain Using PET with <sup>11</sup>C-AC-5216
AID  - 10.2967/jnumed.109.062554
DP  - 2009 Jul 01
TA  - Journal of Nuclear Medicine
PG  - 1095--1101
VI  - 50
IP  - 7
4099  - http://jnm.snmjournals.org/content/50/7/1095.short
4100  - http://jnm.snmjournals.org/content/50/7/1095.full
SO  - J Nucl Med2009 Jul 01; 50
AB  - Peripheral benzodiazepine receptor (PBR) is upregulated in activated glial cells and is therefore a useful biomarker for inflammation in the brain and neurodegenerative disorders. We developed a new PET radioligand, 11C-AC-N-benzyl-N-ethyl-2-(7-methyl-8-oxo-2-pheyl-7,8-dihydro-9H-purin-9-yl)acetamide (11C-AC-5216), that allows the imaging and quantification of PBRs in monkey and mouse brains. The aim of this study was to evaluate a quantification method of 11C-AC-5216 binding in the human brain. Methods: A 90-min dynamic PET scan was obtained for each of 12 healthy men after an intravenous injection of 11C-AC-5216. Regions of interest were drawn on several brain regions. Binding potential, compared with nondisplaceable uptake (BPND), was calculated by a nonlinear least-squares fitting (NLS) method with the 2-tissue-compartment model, and total volume of distribution (VT) was estimated by NLS and graphical analysis methods. Results: BPND was highest in the thalamus (4.6 ± 1.0) and lowest in the striatum (3.5 ± 0.7). VT obtained by NLS or graphical analysis showed regional distribution similar to BPND. However, there was no correlation between BPND and VT because of the interindividual variation of K1/k2. BPND obtained with data from a scan time of 60 min was in good agreement with that from a scan time of 90 min (r = 0.87). Conclusion: Regional distribution of 11C-AC-5216 was in good agreement with previous PET studies of PBRs in the human brain. BPND is more appropriate for estimating 11C-AC-5216 binding than is VT because of the interindividual variation of K1/k2. 11C-AC-5216 is a promising PET ligand for quantifying PBR in the human brain.