Photon Factory Activity Report 2017 #35 (2018)

BL-14C/2017G171

Small Animal Tumor Visualized by Three-Dimensional Phase-Contrast X-ray
Computed Tomography

THET THET LWIN1,* AKIO YONEYAMA2, HIROKO MARUYAMA1, KAZUYUKI HYODO3,TOHORU TAKEDA1
1
School of Allied Health Sciences, Kitasato University, Kanagawa 252-0373, Japan,
2
Saga light source, Saga 841-0005, Japan
3
High Energy Accelerator Research Organizations, Tsukuba 305-0801, Japan
1 Introduction
Currently used conventional X-ray CT images aregenerated from the differences in X-ray absorption.
However biological soft tissue consisting of low atomic
number such as H, C, N, and O, does not have enough Xray absorption differences. Thus, high contrast resolution
soft tissue image is required. Since cross section of X-ray
phase shift is approximately 1000 times higher than thatof absorption for low atomic numbers elements, phasecontrast X-ray CT enables to depict the internal structuresof biological of soft tissue without contrast agents [1-5].
Here, we determine the feasibility to reveal the cancer
morphology and its vascular structures in small animaltumors.
2 ExperimentThis study used spontaneous development of brain
tumor and testicular tumor of old rats (age, 2 years).
Using two-crystal interferometer based phase-contrast Xray imaging system [6], we obtained images of old rat’s
brain and testicular tumors. The X-ray energy was set at
35keV. Experiment was performed at the vertical wiggler
beam line 14C of the Photon Factory, Tsukuba, Japan.
Two and three-dimensional images were reconstructedusing 3D volume-rending software (Real INTAGE; KGT
Inc., Japan).
After phase-contrast X-ray CT examination, allspecimens were sliced into 3-µm-thick sections andstained with Hematoxylin and Eosin (HE). All images
were compared with corresponding pathological pictures.
The experimental protocol was approved by thePresident of Kitasato University through the judgment ofthe Animal Care and Use Committee of Kitasato
University.
3 Results and Discussion
Phase-contrast X-ray CT without contrast agent,
enabled to clearly demonstrate pathological andanatomical structures of rat’s brain such as tumor locatedin the brain stem, cortex, caudate putamen, hippocampus,
and corpus callosum [7]. Phase-contrast X-ray CT also
revealed the rat’ testes including seminiferous tubules,
tunica albuginea, blood vessels and interstitial tumors(Fig1. A). Both tumors were well differentiated from thesurrounding normal tissue. Various pathological featuresof tumor, e.g., its cell density and microvasculature, andblood clots caused by hemorrhaging and/or hematomas,
were clearly observed in three-dimensional images.

Phase-contrast X-ray CT images resembled pathologicalpictures with a magnification of ×20 in two dimensional
image. In addition, tumor vascularity up to approximately
26 µm in diameter were clearly visible in threedimensional images (Fig.1 B).
Phase-contrast X-ray CT enabled to depict the tumor
morphology,
especially
micro-vasculatures
onspontaneous tumor of small animals.

Fig. 1: Phase Contrast X-ray CT image.
Three-dimensional reconstruction image of testes withtumor (A), Three-dimensional reconstruction image oftumor microvasculature (B).
Acknowledgement
This study was approved by KEK proposal number
2016G034 and 2017G171.
References[1] A Momose and J Fukuda. Med Phys. 22, 375 (1995)[2] T Takeda et al.,Acad. Radiol. 2, 799 (1995)[3] T Takeda et al., Radiology. 214: 298 (2000)[4] K Noda-Saita et al., Neuroscience 138:1205 (2006)[5] J Wu et al., Kidney International. 75:945-51 (2009)[6] A. Yoneyama, et al, 425, 192007, J. Phys.: Conference
Series (2013)[7] L Thet Thet., Acta Radiol Open. 5 (2)2058460115626958 (2017)*ttlwin @kitasato-u.ac.jp