INSTITUTE OF PHYSICS PUBLISHING PHYSICS IN MEDICINE AND BIOLOGY Phys. Med. Biol. 49 (2004) 501–508 PII: S0031-9155(04)69923-4 Synchrotron microangiography with no contrast agent Y Hwu 1 , W L Tsai 1 , J H Je 2 , S K Seol 2 , Bora Kim 2 , A Groso 3 , G Margaritondo 3 , Kyu-Ho Lee 4 and Je-Kyung Seong 4 1 Institute of Physics, Academia Sinica, 128 Academia Rd, Nankang, Taipei, Taiwan 2 Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, Korea 3 Facult´ e des sciences de base, Ecole Polytechnique F´ ed´ erale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland 4 Medical Research Center, Yonsei University College of Medicine, Seoul, Korea Received 2 October 2003, in final form 4 December 2003 Published 27 January 2004 Online at stacks.iop.org/PMB/49/501 (DOI: 10.1088/0031-9155/49/4/002) Abstract Coherent x-rays from synchrotron sources are increasingly used in non- conventional radiological techniques (‘phase-contrast’ radiology). Our experiments demonstrate that by using white (unmonochromatic) radiation and a time-resolving system, it is possible to image microscopic details of moving blood vessels in different live animals without using any contrast agent. The images have excellent contrast plus unprecedented spatial resolution for microangiography (<10 μm). This result is likely to impact many different areas of biological and medical research and of diagnostic radiology. 1. Introduction The detection of small internal structures of live systems has been a major problem since R¨ ontgen’s discovery of x-rays (R¨ ontgen 1896). In particular, limited contrast and the consequent need for a contrast agent sharply limit the use of angiography both in diagnostic radiology and in biomedical research. Highly coherent synchrotron x-ray sources provide a novel solution based on non-conventional contrast mechanisms (Fitzgerald 2000). Our practical tests show that an unmonochromatic synchrotron beam is perfectly suitable to take advantage of the phase contrast and obtain high quality images. Furthermore, without spectral filtering the signal is sufficiently high for imaging in real time (down to less than 1 ms). These performances were exploited to produce real-time images of micron-level features in blood vessels of different animals—with no contrast agent. These results are unprecedented in angiography. Specifically, tomography and magnetic resonance imaging can sometimes provide better image quality than conventional radiology. However, they cannot detect fine structures of several-micron size, useful for the early diagnosis not only of vascular diseases but also of tumours and for other medical and biological objectives (Furman-Haran et al 1998, Laib and R ¨ uegsegger 1999, Majumdar et al 1998). 0031-9155/04/040501+08$30.00 © 2004 IOP Publishing Ltd Printed in the UK 501