RTK wiki help

From Openrtk
(Redirected from Main Page)
Jump to: navigation, search

Welcome to RTK

The Reconstruction Toolkit (RTK) is an open-source and cross-platform software for fast circular cone-beam CT reconstruction based on the Insight Toolkit (ITK). RTK is developed by the RTK consortium. This is the wiki documentation, other information is available here:

Main website



Contact us

RTK is an open source C++ library, not an executable. This means that you must write code that uses RTK and compile it before you will obtain something that you can run and get a result from. It also means that you can adapt or extend RTK to address your problem at hand. To facilitate this over multiple operating systems, compilers, and system configurations, RTK itself must be built from its source code. RTK is based on The Insight Toolkit, therefore you would need to get, configure and compile The Insight Toolkit first.

The three steps to starting to work with RTK are therefore:

  1. Download and Build the ITK source
  2. Download/Obtain/Get the RTK source
  3. Build the RTK library
  4. Write your own code that uses RTK and build it, linking to the RTK library.

In the next sections we describe each of these steps. Danny Lessio has developped and shared a script that automatically downloads and compiles ITK and RTK, see the auto-build-RTK GitHub repository.


In order to compile RTK you will need the following:

  • GIT (in order to get the software)
  • CMake (in order to configure RTK)
  • C/C++ compiler

Step 0 - Getting ITK

RTK currently uses ITK > 4.2.0.

We recommend to look into the ITK wiki in order to compile ITK for your system. The documentation for ITK should be fairly straight forward. Moreover, the concepts for building ITK are very similar to those for RTK. In order to get ITK 4.5.1:

 git clone git://itk.org/ITK.git
 cd ITK
 git checkout v4.5.1

Once ITK source code is downloaded you need to configure and generate the CMake files:

 mkdir ITK-bin
 cd ITK-bin
 ccmake ../ITK

RTK requires the following option

 Module_ITKReview ON

It is also recommended to use the FFTW library via the options


Note that you do not need to build the examples, the documentation or any of the tests to use ITK with RTK. You can set them off in order to speed up the process with the following flags:


After generating your CMake files you are ready to start the compilation process, run:


Step 1 - Getting RTK

This page documents how to download RTK through Git. Follow the ITK Git download instructions to install Git.

To get the latest source code for RTK:

 git clone git://github.com/SimonRit/RTK.git

Step 2 - Building RTK

Like ITK, in order to build RTK you would need to install [CMake www.cmake.org]. CMake supports out of source build so we recommend to create a binary directory 'RTK-bin'

 mkdir RTK-bin
 cd RTK-bin
 ccmake ../RTK

When CMake asks for the ITK_DIR, specify the binary directory where ITK is built and choose CMAKE_BUILD_TYPE (default: Release),

 ITK_DIR /path_to_directory/ITK-bin

Finally, after configuring and generating your CMake files, you can start the compilation running the following command:


Step 3 - Running the HelloWorld application

In order to verify the installation of your RTK library, you can run the HelloWorld application. This application is part of the RTK examples and should be built by default. Otherwise make sure that


when configuring RTK with CMake.


Another installation solution is to use the Docker solution provided by Thomas Baudier:

 docker pull tbaudier/rtk:v1.3.0
 docker run -ti --rm -e DISPLAY=$DISPLAY -v [Documents]:/home tbaudier/rtk:v1.3.0 bash

Information on what is installed can be reached using the commands:

 docker images
 docker ps -a

To clean it after use, you can do:

 docker rm -f [container id]
 docker rmi -f [image id]


Tutorial 0 - Building a HelloWorld application with RTK

RTK is a library, therefore it's meant to be integrated into application. This tutorial shows how to create a simple HelloWorld project that links with RTK. The source code for this tutorial is located in RTK/examples/HelloWorld.

  • First you need to create a CMakeLists.txt with the following lines:
 # This project is designed to be built outside the RTK source tree.
 # Find the RTK libraries and includes
 # Executable
 ADD_EXECUTABLE(HelloWorld HelloWorld.cxx )
  • Create a HelloWorld.cxx file
 #include <rtkFDKBackProjectionImageFilter.h>
 int main(int argc, char **argv)
 // Define the type of pixel and the image dimension
 typedef float OutputPixelType;
 const unsigned int Dimension = 3;
 // Define the type of image
 typedef itk::Image< OutputPixelType, Dimension > OutputImageType;
 // Define and allocate the FDK Back Projection Filter
 typedef rtk::FDKBackProjectionImageFilter<OutputImageType, OutputImageType> BPType;
 BPType::Pointer p = BPType::New();
 std::cout << "RTK Hello World!" << std::endl;
 return 0;
  • Run CMake on the HelloWorld directory and create a HelloWorld-bin
  • Configure and build the project using your favorite compiler
  • Run the HelloWorld application. If everything runs correctly you should see "RTK Hello World!" written on the console.

Tutorial 1 - Modifying a basic RTK application

In RTK/applications/rtktutorialapplication/, you will find a very basic RTK application that can be used as a starting point for building more complex applications. The code suggests ways to modify the application, which should help beginners get the hang of ITK and RTK.

Tutorial 2 - My first reconstruction

Reconstruct a Sphere


SimpleRTK provides a wrapping mechanism to several languages such as Python and C#.

WaterPreCorrection is an example of SimpleRTK processing to correct for cupping.

FanBeam is an example of SimpleRTK processing to do 2D fan-beam reconstructions.


RTK also provide a set of command line applications that are compiled if the cmake option BUILD_APPLICATIONS is turned on. Each application uses [gengetopt] to allow parsing of the command line options. The manual of each application can be obtained with the --help or -h option. They can be executed sequentially in bash scripts. We provide below links to examples of use for RTK applications.

Image quality

Summary of existing and future developments for image quality in RTK


The description of the 3D circular geometry is based on the international standard IEC 61217 which has been designed for cone-beam imagers on isocentric radiotherapy systems, but it can be used for any 3D circular trajectory. The fixed coordinate system of RTK and the fixed coordinate system of IEC 61217 are the same. A clear understanding of the geometry is essential for the use of a tomography package. The geometry description has been written in a latex document compiled here.

ImagX geometry

We provide as an example of geometry conversion the File:GeometryImagX.pdf specifications of the geometry used by the ImagX project (IBA/UCL) with the File:GeometryImagX.txt script file developed in Maxima to do the conversion.

Developer's corner

Developer's documentation

We only provide the doxygen documentation at the moment.

Coding style

RTK is based on ITK and aims at following its coding conventions. Any developer should follow these conventions when submitting new code or contributions to the existing one. We strongly recommend you to read thoroughly ITK's style guide.