Submitted by Dr. Ge Wang (ge-wang@ieee.org) on July 10, 2000, to:

Ms. Nancy Vazquez, Program Manager American Association of Physicists in Medicine One Physics Ellipse College Park, MD 20740-3846 Phone: (301) 209-3350 Fax: (301) 209-0862 http://www.aapm.org	Dr. Charles Lescrenier C/o Nancy Vazquez AAPM One Physics Ellipse College Park, MD 20740-3846 Phone: (301) 209-3350 Fax: (301) 209-0862
Dr. Robert W. Neilson, General Secretary Institute of Physics and Engineering in Medicine Fairmount House, 230 Tadcaster Road York, YO24 1ES, UK Phone: (+44) (0) 1904 610821 Fax: (+44) (0) 1904 612279 office@ipem.org.uk	Dr. Michael Sandhu Varian Medical Systems UK Ltd. Gatwick Road Crawley West Sussex RH10 2RG, UK Phone: (+44) (0) 1293 531244

Report on Ge Wang's European Trip with the AAPM/IPEM Travel Award 1999

It was my honor and privilege to receive the AAPM/IPEM Medical Physics Travel Award 1999, setup by Charles Lescrenier, Varian Medical Systems UK Ltd., the AAPM and the IPEM. As highlighted in the letter of April 29, 1999, by Nancy Vazquez, Program Manager of the AAPM, "This award is an important component of the AAPM program to improve interactions between medical physicists in the United States and other countries." Under support of this the AAPM/IPEM Award, I visited Germany, the UK and France in June 2000.

During this visit, I learned extensively from my European colleagues about their ideas, results, plans and visions. Also, we discussed collaborative possibilities. My impressions are briefly reported as follows, which are hopefully representative of the trip.

In Germany, I visited the famous Institute of Medical Physics, University of Erlangen, Germany (http://www.imp.uni-erlangen.de) headed by Dr. Kalender, who is a major pioneer of spiral/helical CT. The Institute began its work in cardiac CT imaging in 1996. The basic idea is to use a synchronously recorded electrocardiogram (EKG) for image reconstruction. Only those data points are used that are assigned to a freely selectable heart phase. Encouraging results of this technique were presented in 1997 with single-slice CT scanners. For the first time it was possible to depict the heart with conventional CT scanners in high 3D resolution consistently and without motion artifacts when images are reconstructed for slow motion phases. The new generation of multi-slice CT scanners added tremendously to the potential of cardiac imaging. Active research in the Institute continues along this direction. Also, other important work there includes reduction of X-ray CT dose and development of a micro-CT system which allows various scanning loci.

In the UK, I first met with colleagues at Imperial College, from the Department of Imaging (http://www.med.ic.ac.uk/dd/courses/dip_img.html) and the Department of Materials (http://www.mt.ic.ac.uk). It was informative for me to realize the overlap between their imaging interests in biomedical and material applications. Actually, the imaging needs of the Department of Materials are quite comparable to that of small animal studies. Dr. Peter Lee's excellent imaging studies on material properties indicated significant collaborative possibilities. Next, I visited University of Cambridge. Prof. Dixon of the Department of Radiology, who is Editor-in-Chief of Clinical Radiology, and his colleagues described their outstanding programs in major aspects of medical imaging (http://www.medschl.cam.ac.uk/rad/radiol.html). Especially, Prof. Dixon and I discussed important issues and main trends of the field. A particularly valuable lesson they gave me was about assessment and reduction of X-ray dose. Then, I traveled to College of Engineering, University of Oxford (http://www.eng.ox.ac.uk). Drs. Rockett and Dobson have a micro-CT project in collaboration with leading experts in various areas. I was deeply impressed by their micro-CT system and its unique potential applications in biomedical, material and industrial fields. They are resubmitting a grant application for the Multi-Project Research Equipment Funding and would like to collaborate with me on the software development. As we discussed, this could take the form of a jointly supervised PhD students or postdoctoral researchers. At Oxford, I also had discussions with Prof. Elliott (j.c.elliott@mds.qmw.ac.uk, http://www.mds.qmw.ac.uk/dbiophysics). Finally, I visited St. George's Hospital (http://www.sghphy.demon.co.uk). In the hospital, there is the UK's CT scanner evaluation center - ImPACT, funded by the Medical Devices Agency, providing a wide range of CT scanner related services. Dr. Edyvean, who is the ImPACT Manager, and her colleagues updated me with their current work, including evaluation of dose and imaging performance of CT scanners, assessment of their user interface, and several research projects. Their well-established blue cover reports are a source of essential scanner information. They also run "ImPACT days" (CT scanner technology education days), and is playing an active role in the newly formed CT Users Group.

In France, I visited Drs. Herment, Giron, Todd-Pokropek of Department of Radiology, University of Paris (http://www.imed.jussieu.fr/Serveur/). Their medical imaging and image analysis programs are extremely strong, quite diversified and in great depth. Especially, I noticed some similarities between their MRI imaging research and our X-ray CT work. They applied a regularized iterative approach for reconstruction of MR images from sparse/partial data. Also, they studied the synthesis of an isotropic high resolution MR image from images that have anisotropically degraded resolutions.

In this trip, I gave six presentations on five topics as follows:

1. Multi-slice spiral CT (June 9, 2000)
Institute of Medical Physics
University of Erlangen, Germany
Contacts:
W. Kalender, willi@imp.uni-erlangen.de
M. Kachelrieb, marc@imp.uni-erlangen.de
T. Fuchs, theo@imp.uni-erlangen.de

2. CT image restoration based on I-divergence minimization (June 12, 2000)
Department of Materials
Department of Imaging
Imperial College, UK
Contacts:
P. Lee, p.d.lee@ic.ac.uk
G. Bydder, graeme.bydder@csc.mrc.ac.uk

3. X-ray CT - Imaging and analysis (June 14, 2000)
Department of Radiology
University of Cambridge, UK
Contacts:
A. Dixon, akd15@radiol.cam.ac.uk
S. Thomas, simon.thomas@msexc.addenbrookes.anglox.nhs.uk

4. Cone-beam spiral CT (June 16, 2000)
College of Engineering
University of Oxford, UK
Contacts:
P. Rockett, peter.rockett@eng.ox.ac.uk
P. Dobson, peter.dobson@eng.ox.ac.uk

5. Cone-beam spiral CT (June 19, 2000)
Department of Medical Physics
St. George's Hospital, UK
Contact:
S. Edyvean, sue@sghphy.demon.co.uk

6. Fast iterative metal artifact reduction (June 23, 2000)
Department of Radiology
University of Paris, France
Contacts:
A. Todd-Pokropek, A.Todd@ucl.ac.uk
A. Herment, herment@imed.jussieu.fr
A. Giron, Alain.Giron@imed.jussieu.fr

These presentations, along with this report, are posted on my European Trip website: http://dolphin.radiology.uiowa.edu/ge/EUROTrip/euro.html. To my knowledge, all of my talks were well received. Also, I was inspired by a number of sharp questions from the audience.

In addition to the academic activities, this journey was wonderful for sightseeing. The top two of my favorites are the Millennium Dome in London (http://www.dome2000.co.uk) and the Eiffel Tower in Paris (http://www.tour-eiffel.fr/indexuk.html). Both of the architectures are characterized by elegant combination of artistic creativity and engineering ambition. The greatness of the masterpieces can be clearly appreciated even if you just visit their web pages. Thanks to Profs. Dixon, Dobson and Rockett, the tours of the University of Cambridge and the University of Oxford were the most touching when we were in or walked around the buildings that are associated with the greatest giants (Newton, Maxwell, Hawking, et al.) and their landmark theories/findings. Being there, you may likely have a unique and profound feeling about the legends, the intelligence and the excitement.

Due to the finite time available, some scheduling limitations, and my lack of knowledge, I must have missed a number of other important centers, laboratories, groups and individuals during this trip. Hopefully, we will have other chances for interaction. Overall, I consider the experience highly rewarding for promoting exchange of ideas and fostering collaborations across the two continents, hence I am deeply grateful to all of those who made it possible. I would like to conclude with an open invitation to our European colleagues - whenever you are interested and have a chance, please contact us so that we can have an opportunity to welcome you in the United States.