<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> <title></title> </head> <body bgcolor="#ffffff" text="#000000"> Hi, I have a question about the following command in the GATE digitizer because I am not sure I really understand what it means: To exclude false coincidence coming from the same particle that scattered from a block to an adjacent block, a test is done on the proximity of the two blocks forming the coincidence event. By default, the coincidence is valid only if the difference in the block numbers is greater than two. This rejection can be adapted to a more specific analysis by using the command: <pre>/gate/digitizer/Coincidences/minSectorDifference [number] First of all, what does block mean? It's not one of the key words of any of the PET systems description (rsector, module, submodule, crystal, layer)? Is it used for module or rsector depending on how the level of readout is defined with the command: /gate/digitizer/Singles/readout/setDepth 1 ? a) In case we chose setDepth 1, does it mean that the coincidence will be kept only if rsectorID1 - rsectorID2 >= 2? b) In case we chose setDepth 2, does it mean that the coincidence will be kept only if moduleID1 - moduleID2 >= 2? If a), I understand that the rejection is radially dependent on the position of the block (there is only 1 rsector in the axial direction) but if b), the rejection is axially dependent on the position of the block (as the modules are numbered per rsector). Could someone help me and tell me if I am correct of not? Thanks a lot, </pre> <div class="moz-signature">-- Corinne <link rel="important stylesheet" href="chrome://messenger/skin/messageBody.css"> <title>message</title> <div class="moz-text-html" lang="x-western"> <div style="text-align: center;"> <div style="text-align: left;"> <hr style="width: 100%; height: 2px;">Corinne J. Groiselle, PhD </div> <div style="text-align: left; font-family: times new roman,times,serif; color: rgb(102, 102, 102);">Research instructor Division of Nuclear Medicine / Department of Radiology University of Massachusetts Medical School 55 Lake Avenue North Worcester, MA 01655 USA phone: (508)-856-6123 - fax: (508)-856-4572 e-mail: <a class="moz-txt-link-abbreviated" href="mailto:Corinne.Groiselle@umassmed.edu">Corinne.Groiselle@umassmed.edu</a> professional homepage: <a class="moz-txt-link-freetext" href="http://users.umassmed.edu/corinne.groiselle">http://users.umassmed.edu/corinne.groiselle</a> personal homepage: <a class="moz-txt-link-freetext" href="http://corinne.groiselle.free.fr">http://corinne.groiselle.free.fr</a> </div> </div> </div> </div> </body> </html>