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From UCL HEP PBT Wiki

Revision as of 13:42, 2 July 2014

Introduction

This is a tutorial about applications of GEANT4 to medical physics. The GEANT4 is installed on the HEP Linux cluster at UCL. You will need an account on that cluster to be able to use this software, run example tutorials and create your own applications.

Accounts and Registration

Getting a computing account

Apply for a computing account on the HEP Linux cluster by sending e-mail to HEPComputingSupport. In your e-mail you have to state the reason for your application (i.e. medical physics student who will use the GEANT4 software on the HEP cluster).

You will receive an e-mail from the HEP computing support with your username and password. Now you can log in to the HEP cluster “plus1” via ssh username@plus1.hep.ucl.ac.uk.

Where to get help

You can send e-mail to the GEANT4 support at GEANT4Support or write to the forum.

The basics of GEANT4

GEANT4 is a toolkit for simulating the passage of particles through matter. The user creates his/her own simulation application using GEANT4 tools. The tools are base classes. There are eight base classes:

• Three classes are mandatory

G4VUserDetectorConstruction

Describe the experimental setup, geometry and materials

G4VUserPhysicsList

Define particles, physics processes and range cuts

G4UserPrimaryGeneratorAction

Describe particle source, source dimensions, initial position, energy spectrum, angular distributions

• The rest are optional

G4UserRunAction

Define and store histograms

G4UserEventAction

Event selection and analysis of simulation data

G4UserStackingAction

Customize priority of tracks

G4UserTrackingAction

Decide whether a trajectory should be stored or not

G4UserSteppingAction

Kill, suspend, postpone a track

You can create your own classes which are derived from the base classes. All of them should be registered with the G4RunManager. In function main() which is the skeleton of the user simulation code you instantiate G4RunManager and notify it of your mandatory and optional classes.

Basic examples

Monoenergetic photon pencil beam incident on a water cube

• Introduction

This example shows the dose distribution in water along the incident photon beam. The beam hits the water cube surface and deposits a dose under the surface of the water. The volume of the water cube is divided into voxels. At each voxel the dose contribution from the pencil beams is summed up and yields the total dose along the beam axis.

• Setting up the environment

1. Connect to plus1 cluster and create a folder PhotonPencilBeam in your local area

ssh username@plus1.hep.ucl.ac.uk mkdir PhotonPencilBeam cd PhotonPencilBeam

2. Setup GEANT4 environment

source ... (GEANT4 script)

• How to get the code

Copy the code to your area

cp /vasileva/BasicExamples/PhotonPencilBeam_source /username/PhotonPencilBeam/

• How to run the code

1. Inside /username/PhotonPencilBeam/ create a folder

mkdir PhotonPencilBeam_build

2. Change to this directory and run cmake and make to build the PhotonPencilBeam example

cd PhotonPencilBeam_build cmake -DGeant4_DIR=/unix/pbt/Software/..../ /username/PhotonPencilBeam_source/ make

• How to analyze data

Monoenergetic proton pencil beam incident on a water cube

• Introduction
• Setting up the environment
• How to get the code
• How to run the code
• How to analyze data
• Comparison with data from The Clatterbridge Cancer Centre

Proton beam with realistic geometry incident on a water cube

• Introduction
• Setting up the environment
• How to get the code
• How to run the code
• How to analyze data
• Comparison with data from The Clatterbridge Cancer Centre

Several proton beams with spread out Bragg peaks

• Introduction
• Setting up the environment
• How to get the code
• How to run the code
• How to analyze data

Advanced examples

Cherenkov simulation

• Introduction
• Setting up the environment
• How to get the code
• How to run the code
• How to analyze data

Computed tomography

• Introduction
• Setting up the environment
• How to get the code
• How to run the code
• How to analyze data

High-precision dosimetry

• Introduction
• Setting up the environment
• How to get the code
• How to run the code
• How to analyze data

Installing GEANT4 software locally