QT software is the property of CPO-Piemonte, Turin (Italy). QT scientific and intellectual property rights belong to the public bodies, researchers and information technology experts that developed QT. The right to use QT is given free-of-charge upon request for non-commercial use. Such right-to-use is conditional upon the user registering as the end-user. The publication (whether printed, on electronic media or CD-ROM) or electronic transmission of data or indicators that originate from the use of QT, must make mention of the software used, as follows: "European Breast Screening Network, Italian Breast Screening Group (G.I.S.Ma.), QT, 2005". CPO-Piemonte and the other authors of QT decline all liability for any direct or indirect damage suffered by the user or third parties arising out of the use of the software. As for all computer files, it is recommended that data files be frequently backed-up onto diskette. Any operational errors in QT must be duly reported to the authors, in the usual spirit of collaboration, so that measures may be taken to correct them in subsequent versions. A user can request the QT authors to make software changes and introduce new features for uses that were not envisaged in the official version. In this case, any required work will be contracted with CPO-Piemonte which shall have intellectual and scientific rights over the changes or new software and shall have the right to incorporate the improvements into subsequent versions of QT. Any changes or new features implemented directly by the user are only permitted for his own use and are subject to prior written authorisation. All changes or additions made to the software shall be passed to CPO-Piemonte in electronic (file) form, without compensation, and may be used in subsequent versions of QT. Intellectual and scientific rights over the changes or additional software remain with CPO-Piemonte. In this case, the contribution made by the public body or researcher that produced the change or new feature shall be recognised in QT software documentation.