Computed tomography
From UCL HEP PBT Wiki
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This tutorial will based on the DICOM GEANT4 example originally developed by Louis Archambault, Luc Beaulieu and Vincent Hubert-Tremblay. In this example a list of DICOM files (.dcm) are converted to ASCII files (.g4dcm) and binary (.g4bin) that can be read by GEANT4. Each of these files corresponds to a Z slice. Then, the .g4dcm (.g4bin) files are merged into one unique volume and used by GEANT4 to construct the patient geometry and materials. | This tutorial will based on the DICOM GEANT4 example originally developed by Louis Archambault, Luc Beaulieu and Vincent Hubert-Tremblay. In this example a list of DICOM files (.dcm) are converted to ASCII files (.g4dcm) and binary (.g4bin) that can be read by GEANT4. Each of these files corresponds to a Z slice. Then, the .g4dcm (.g4bin) files are merged into one unique volume and used by GEANT4 to construct the patient geometry and materials. | ||
| - | The geometry is constructed by voxelizing the volume. There are four navigation algorithms used to create the voxel geometry: G4SmartVoxel, G4VNestedParameterisation, G4RegularNavigation and | + | The geometry is constructed by voxelizing the volume. There are four navigation algorithms used to create the voxel geometry: '''G4SmartVoxel''', '''G4VNestedParameterisation''', '''G4RegularNavigation''' and '''G4PVReplica'''. In this tutorial we investigate the different geometry implementations. |
The material is constructed by converting the pixel values (Hounsfield numbers) from the DICOM images to densities using | The material is constructed by converting the pixel values (Hounsfield numbers) from the DICOM images to densities using | ||
the [http://www.hep.ucl.ac.uk/pbt/RadiotherapyWorkbook/skins/common/images/DICOM/CT2Density.dat Hounsfield scale]. Then, the densities are converted to material type according to this [http://www.hep.ucl.ac.uk/pbt/RadiotherapyWorkbook/skins/common/images/DICOM/Materials.txt table]. | the [http://www.hep.ucl.ac.uk/pbt/RadiotherapyWorkbook/skins/common/images/DICOM/CT2Density.dat Hounsfield scale]. Then, the densities are converted to material type according to this [http://www.hep.ucl.ac.uk/pbt/RadiotherapyWorkbook/skins/common/images/DICOM/Materials.txt table]. | ||
| - | A simple monenergetic electron beam is simulated | + | A simple monenergetic electron beam is simulated using '''G4ParticleGun''' class. The output of the tutorial is a text file with dose deposition in several voxels. |
http://www.hep.ucl.ac.uk/pbt/RadiotherapyWorkbook/skins/common/images/DICOM/dicom.png | http://www.hep.ucl.ac.uk/pbt/RadiotherapyWorkbook/skins/common/images/DICOM/dicom.png | ||
