<HTML> <HEAD> <TITLE>Re: [Gate-users] Transmission tomography</TITLE> </HEAD> <BODY> Hi Javier, While it is technically possible to simulate an x-ray CT, the amount of photons you would need is prohibitive.  I have done simulations of a microCT scanner and even to get a single projection with a noise level comparable to a real scanner, about 10^10 photons were required which can take easily hundreds of hours of cpu time.  A full microCT scan would be 10^13 photons and , for a clinical scanner, this number would be much higher.  I don’t think x-ray CT simulations can be performed in a practical manner with GATE. Richard On 5/21/08 5:18 AM, "Javier Serrano" <fjaviersr@usal.es> wrote: <BLOCKQUOTE><TT>Hello. I'm new with Gate and also in computed tomography. I have seen that Gate permits to simulate PET and SPECT scanners. I think that in these types of tomography the source is a radioisotope injected into the patient. Sorry if I'm wrong. I would like to simulate a scanner for transmission tomography. My question is: Is it possible to use Gate to simulate an x-ray scanner with an external cone-beam source? Thank you. Fº Javier Serrano Rodriguez Department of Computer Science and Automation University of Salamanca - Spain _______________________________________________ Gate-users mailing list Gate-users@lists.healthgrid.org <a href="http://lists.healthgrid.org/mailman/listinfo/gate-users">http://lists.healthgrid.org/mailman/listinfo/gate-users</a> </TT></BLOCKQUOTE><TT> </TT> -- Richard Taschereau, Ph.D. Crump Institute for Molecular Imaging University of California Los Angeles 700 Westwood Plaza, A222 Los Angeles, CA 90095-1770 Phone: (310) 825-0697 Fax:     (310) 206-8975 email: RTaschereau@mednet.ucla.edu ---------------------------------------------------------- IMPORTANT WARNING: This email (and any attachments) is only intended for the use of the person or entity to which it is addressed, and may contain information that is privileged and confidential. You, the recipient, are obligated to maintain it in a safe, secure and confidential manner. Unauthorized redisclosure or failure to maintain confidentiality may subject you to federal and state penalties. If you are not the intended recipient, please immediately notify us by return email, and delete this message from your computer. ---------------------------------------------------------- </BODY> </HTML>