CustusX is licensed under the BSD-3 license, which means you can use the application for whatever you wish. Plugins can have other lisenses, but the plugins bundled inside the CustusX repository use the same license as CustusX. CustusX is built on top of several other open-source libraries, with their own licenses. They are listed here: External libraries.

This is the full CustusX license:

    Copyright (c) 2008-2018, SINTEF Department of Medical Technology
    All rights reserved.

    Redistribution and use in source and binary forms, with or without 
    modification, are permitted provided that the following conditions are met:

    1. Redistributions of source code must retain the above copyright notice, 
       this list of conditions and the following disclaimer.

    2. Redistributions in binary form must reproduce the above copyright notice, 
       this list of conditions and the following disclaimer in the documentation 
       and/or other materials provided with the distribution.

    3. Neither the name of the copyright holder nor the names of its contributors 
       may be used to endorse or promote products derived from this software 
       without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE 
    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 
    OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.