DICOM Extended Example

Overview

Scope of the DICOM example is to demonstrate how to construct a Geant4 geometry starting from real computed tomography (CT) patient data. Moreover it provides different navigation methods to speed-up simulation in a voxelised environment.

The DICOM example converts a list of DICOM files (.dcm) to ASCII files (.g4dcm) and binary (.g4bin) that can be read by Geant4. This file are used by Geant4 to construct a voxelised geometry describing single patient geometry. The text files contain Hounsfield numbers describing a CT-calibration phantom (PhantomCT.jpg) and are converted to densities according to a conversion table provided in the file CT2density.dat (scanner specific). A Geant4 geometry is then created for the phantom using the G4PhantomParameterisation class.

The example simulate a simple monenergetic electron beam inside the patient. The output of the example is a 3D dose (Gy) deposited inside the patient.

The example is located in the geant4/examples/extended/medical/DICOM tree.

The following files can be found in the DICOM directory:

File Content
Data.dat it contains the input information for reading DICOM files
dicom.cc main
PhantomCT.jpg image of the phantom used for CT calibration, that is the same of the DICOM images
vis.mac macro file for visualisation using OpenGL
Colourmap.dat it defines the colour of the different DICOM materials
README information on hiw to run the example (Read it first!!!)
CT2Density.dat calibration of HU into materials using the phantom used for CT calibration
run.mac macro for batch mode

extendedexamplesDICOM.jpg

Monoenergetic beam of 6 MeV electrons impinging on a phantom
modelised with the DICOM interface of the DICOM extended example

DICOM reader

This example is not provided to be an universal DICOM reader. You could experience problem if you use CT of different manufaturers respect to the one used in the example. To help you in avoiding these problems we tested the example with CT images coming from the CONQUEST DICOM server that has been developed at the Netherlands Cancer Institute and is freely available on the WEB.

Here there are some suggestion of how could be a reasonable workflow:

0) Install CONQUEST DICOM server on some PC (it works both with Linux and Windows) in the same LAN of your CT scanner

1) DICOM send the CT images of the patient/phantom from your CT scanner to the CONQUEST DICOM server

2) Copy the files into the DICOM example directory and run the example.

ct-thorax.jpg

Patient's thorax modelised with the DICOM interface of the DICOM extended example


Main DICOM page

Main Medical Physics page


Stéphane Chauvie - 07 Jan 2010
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JPEGjpg ct-thorax.jpg r1 manage 208.0 K 2010-01-07 - 12:52 StephaneChauvie Monoenergetic beam of 6 MeV electrons impinging on a Patient's thorax modelised with the DICOM interface of the DICOM extended example
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Topic revision: r8 - 2010-01-07 - StephaneChauvie
 
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