Photon Factory Activity Report 2005 #23 Part B (2006)
Medical Applications

NE5A/2005G308

In-vivo FXCT imaging of mouse brainTohoru TAKEDA1, Jin WU1, Thet-Thet-Lwin1, Satoshi MOURI2,Seita NASUKAWA2, Qingkai HUO1, Naoki SUNAGUCHI2, Tetuya YUASA2,Kazuyuki HYODO3, Takao AKATSUKA2
1
Graduate School of Comprehensive Human Sciences, University of Tsukuba,Tsukuba-shi, Ibaraki 305-8575, Japan
2
Faculty of Engineering, Yamagata University. Yonezawa-shi, Yamagata 992-8510, Japan
3
Institute of Materials Structure Science, High Energy Acceleration Research Organization, JapanIntroduction
The fluorescent X-ray computed tomography (FXCT)with synchrotron radiation is being developed to depict
the distribution of specific elements inside the object
without slicing procedure [1-5]. FXCT system with aspatial resolution less than 0.1 mm and short dataacquisition was constructed by using a germanium
detector with high efficiency and high count-rateelectronics [6]. In-vivo cerebral perfusion imaging of rat& mice has succeeded by FXCT after injecting
non-radioactive iodine labeled cerebral perfusion agent(IMP) [7-10]. However, long time was required to acquire
FXCT image data. For faster data FXCT imaging, wehave improved scanning technique based on Compton
scattering effect.
Methods and material
The experiment was carried out at the bending-magnet
beam line BLNE-5A of the Tristan accumulation ring inTsukuba, Japan. The photon flux rate in front of theobject was approximately 9.3 x 107 photons/mm2/s for abeam current of 40 mA. FXCT system consists of asilicon (220) double crystal monochromator, an x-ray slit
system, a scanning table for subject positioning,
fluorescent X-ray detector, and two pin-diode detectors
for incident X-ray and transmission X-ray data. The white
X-ray beam was monochromatized to 37 keV X-rayenergy. The monochromatic X-ray was collimated into a
1 x 0.1 mm2 pencil beam. Fluorescent X-rays weredetected in a high purity germanium (HPGe) detectors
and the HPGe detector was oriented perpendicular to theincident monochromatic x-ray beam. The data acquisition
time of the HPGe detector for each scanning step was set
5-s. Object was scanned in 1-mm translation step and6-degree rotation step over a range of 180 degrees.
In this experiment, Compton scatter was monitored
simultaneously and used to determine the outside ofobject because Compton scattering signal becomes zeroin the outside of object. Under the anesthesia, the brain ofa mouse was imaged by FXCT after injecting
non-radioactive iodine labeled IMP.

The present experiment was approved by the Medical
Committee for the Use of Animals in Research of theUniversity of Tsukuba, and it conformed to the guidelinesof the American Physiological Society.
Results and discussion
In-vivo cerebral perfusion of mouse determined by theuptake of iodine content was clearly imaged by FXCT at a1 mm spatial resolution with a 0.1 mm slice thickness. By
using new scanning technique, the number of translation
scanning step was reduced significantly, and dataacquisition time was shortened to about 40%. Thus, wecould obtain the image of two slices under the anesthesia,
and the selection of better slice became easy to assess thedisease condition. However, to perform much faster dataacquisition, we are being developed new detector systemwith higher count rate capability.
In-vivo imaging of cerebral perfusion has succeeded byFXCT, and data acquisition time became shorter by using
the new scanning technique.
Acknowledement

We thank Nihon Medi-Physics Co., Ltd., Japansupplying I-127 IMP. This research was partially
supported by a Grant-In-Aid for Scientific Research(#17390326, #15070201, #16-04246) from the Japanese
Ministry of Education, Science and Culture, Research
Grant A 2117 from University of Tsukuba.
References[1] Takeda T, et al. Proc. SPIE 1996; 2708: 685-695[2] Yuasa T, et al. IEEE trans. Nucl. Sci. 1997; 44: 54-62[3] Rust GF, Weigelt J. IEEE Trans.Nucl.Sci. 1998; 45:75-88[4] Takeda T, et al. Nucl. Instr. Meth. 2001; A467-468:1318-1321[5] Yu Q, et al. J. Synchrotron Rad. 2001; 8: 1030-1034[6] Takeda T, et al. AIP Proc. 2004; CP705: 1320-1323[7] Takeda T, et al. PF activity report 2004, #21B:251[8] Takeda T. Nucl. Instr. Meth. 2005; A548:38-46[9] Takeda T, et al. Proc. IEEE ICIP. 2005, III-593-596[10] Takeda T, et al. AIP Proc. 2006 submit.

Users' Report241