Nuclear Instruments and Methods in Physics Research A 467–468 (2001) 1326–1328 Integrated image presentation of transmission and fluorescent X-ray CT using synchrotron radiation T. Zeniya a,b , T. Takeda b, *, Q. Yu a,b , Y. Hasegawa a , K. Hyodo c , T. Yuasa a , Y. Hiranaka a , Y. Itai b , T. Akatsuka a a Faculty of Engineering, Yamagata University, Yonezawa, Yamagata 992-8510, Japan b Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennoudai Tsukuba, Ibaraki 305-8575, Japan c Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan Abstract We have developed a computed tomography (CT) system with synchrotron radiation (SR) to detect fluorescent X-rays and transmitted X-rays simultaneously. Both SR transmission X-ray CT (SR-TXCT) and SR fluorescent X-ray CT (SR-FXCT) can describe cross-sectional images with high spatial and contrast resolutions as compared to conventional CT. TXCT gives morphological information and FXCT gives functional information of organs. So, superposed display system for SR-FXCT and SR-TXCT images has been developed for clinical diagnosis with higher reliability. Preliminary experiment with brain phantom was carried out and the superposition of both images was performed. The superposed SR–CT image gave us both functional and morphological information easily with high reliability, thus demonstrating the usefulness of this system. # 2001 Elsevier Science B.V. All rights reserved. PACS: 87.59.F; 78.70.E; 07.85.Q; 87.62 Keywords: Transmission X-ray CT; Fluorescent X-ray CT; Synchrotron radiation; Superposition; Image understanding 1. Introduction Recently, superposition of functional images on morphological images, i.e. single photon emission computed tomogram (SPECT) on 3D X-ray images has been studied for clear image understanding with high reliability [1]. We have developed a CT system with synchrotron radiation (SR) by detect- ing fluorescent X-rays and transmitted X-rays simultaneously [2–7]. Both transmission X-ray CT (TXCT) and fluorescent X-ray CT (FXCT) can describe the spatial distribution of target materials with higher spatial and contrast resolutions as compared to conventional X-ray CT. FXCT, particularly, is able to depict small amount of specific materials. The sensitivity of FXCT is about 70 times better than that of TXCT [5]. In our present FXCT system, 0.025mg/ml iodine solution was detected with 0.2 Â 0.2mm 2 spatial resolution [6]. Therefore, the understanding of physiological function by using small amounts of non-radioactive contrast materials has come in our hands. How- ever, since FXCT only describes the distribution of target material without tissue structure image, it *Corresponding author. Tel.: +81-298-53-3774; fax: +81- 298-53-3658. E-mail address: ttakeda@md.tsukuba.ac.jp (T. Takeda). 0168-9002/01/$-see front matter # 2001 Elsevier Science B.V. All rights reserved. PII:S0168-9002(01)00658-1