FLUKA

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Information and examples on FLUKA Monte Carlo simulations

FLUKA wiki page for UoB Medphysmc. Here you can return to the main page or the GEANT4 page

Introduction to FLUKA

FLUKA is a general purpose Monte Carlo code and is used for a number of applications in experimental physics, dosimetry, detector design, medical physics and radio-biology.

Flair and Flair-Geoeditor

Flair is the Graphical user interface for FLUKA and is used for preparing the simulation as well as running the simulations, process and plot the data (through Gnuplot). Flair also contain a geometry viewer/editor named flair-geoviewer, which is used for visualization and editing of the simulation geometry.


The Flair-Geoeditor

The Flair-Geoeditor (previously geoviewer)can be used for visualization and edition of the geometry. Several tutorials are available on youtube. See e.g. this tutorial on selection of regions and zones.


Installation and running

Installation

In order to install FLUKA you must, as a registered user, download the necessary software from the FLUKA web-page. At the University of Bergen we use Ubuntu and the 64bit Gfortran version of FLUKA, and this is what we recommend for new users at the university. If you wish to use a Windows-pc you can download FLUPIX. FLUPIX is Linux Live CD, with pre-installed FLUKA, flair and all the necessary tools in for performing fluka runs. In the packages.txt you will find a complete list of the packages currently included in the ISO image. To save disk space, FLUPIX is only able to run through the VirtualBox machine (www.virtualbox.org) a free and open source Virtual machine supported by Sun. More information on FLUPIX can be found here.


If you wish to install FLUKA, Flair and Flair-Geoviewer yourself, you can find a detailed installation guide here

Lectures, presentations and exercises

The best way to learn FLUKA is to attend one of the courses held by the FLUKA-team. If this is not an immediate option you can find a large number of lectures and exercises from both basic courses and advanced courses on the FLUKA web-page. Lectures and exercises from one of the beginners courses are available here.


Local FLUKA projects

2015:

The Influence of the Energy Degrader Material for a Therapeutical Proton Beam - Master thesis work by John Alfred Brennseter

In cyclotron based proton therapy an energy degrader is needed to modulate the proton beam energy. The proton beamenergy decides the range of the particles and thereby where the dose is imparted. The influence of the material of the energy degrader for a 250 MeV therapeutic proton beam has been evaluated with FLUKA, a Monte Carlo based particle transport software. A geometry of a double wedge degrader of beryllium, carbon or lexan and a collimator of copper and carbon has been used. The momentum spread, angular spread, transmission fraction neutron yield and photon yield have been measured.


The thesis is available in pdf format here


A Comparison of Biological Dose Estimates in Proton and Carbon Ion Therapy Based on Averaged and Full Linear Energy Transfer Spectra - Master thesis work by Eivind Rørvik

Radiotherapy with ions, also known as particle therapy, is increasing rapidly. To adapt from the higher biological effectiveness of particles compared to photons, the concept of relative biological effectiveness (RBE) is used. Protons are slightly more effective than photons, and the RBE is set to be constant 1.1. The constant RBE value is not a physical property of the beam, it is simply assigned to be 1.1 by a consensus in the scientifc community. Experiments indicate that the RBE in reality is marginally increasing along with the treatment depth. For carbon ions the variations in RBE are signifcantly higher and typically range between 1 and 3. The variation is taken into account in treatment planning, however, relatively large uncertainties are present in the radiobiological models applied. Many of these models are based on correlations between the calculated linear energy transfer (LET) and experimentally measured RBE. Most phenomenological models are based on the dose averaged LET, LETd. However, it should also be possible to correlate the biological effect to the full dose weighted LET spectrum, d(L). By using a biological weighting function (BWF), it is possible to estimate the RBE from either LETd or d(L). In this work, several proton and carbon ion beams were simulated with the FLUKA Monte Carlo code. The physical absorbed dose and the LET spectrum d(L) were estimated at different depths in a water phantom. A BWF was created upon existing cell experiments databases and applied to quantify the effect of the averaging.

The thesis is available in pdf format here

2014:

Dosimetric Consequences of Dropping the Momentum Analysis System in a Compact Proton Therapy System - Project thesis by Eivind Rørvik

The high investment cost of proton therapy centers could be lowered by building just one single room systems. When a accelerator serves a single treatment room, the beam line could be minimized to cut the cost further. One of the systems available on the market today is cutting the Momentum Analysis system (MAS, Momentum analyser), and degrading the beam directely in front of the patient. The momentum of the beam is then larger compared to other systems, which further enlarges the distal dose falloff, a common dosimetric parameter used in clinics. A higher distal dose falloff will create a higher dose to organs at risk behind the tumor volume, which enlarges the NTCP, as shown in the figure.


In this thesis a simplified 250 MEV proton beam is degraded through PMMA and dropped into a water phantom. The thickness of PMMA is varied to get different clinical relevant ranges. Other proton beams were dropped directly into the water phantom, with realistic ESS/Synchrotron parameters. The bragg curves of the beams were recorded by a usrbin-card in FLUKA, and the range (90%) and distal dose falloff (80%-20%) were analysed by a matlab script. The plot shows the 5 different beams.

As seen, the systems without a momentum analyser have a constant distal dose falloff for all ranges, compared to the ESS/synchrotron systems, which have an almost proportional ratio between the parameters.

At deep treatment depths (prostate etc.), the clinically differences between the systems nearly negligible. But for shallow treatment depths (Breast, spine etc), the should be accounted for. For some conditions, as left sided breast cancer, treatment with such a system MIGHT not be favoured over high precision photon therapy. Multiple dose plans should be made and compared for these potential cancer type, to either confirm or rule out the possible dosimetric consequence of dropping the MAS.

The thesis was written in a project course at NTNU under supervision of Pål Erik Goa, in collaboration with Kristian Smeland Ytre-Hauge.

Files:

Fluka input file (change from .txt to .inp)

Flair file

Project report


Simulations of Neutron Fluence Through Concrete Wall in Proton Therapy - Project thesis by John Alfred Brennsæter

In proton therapy secondary particles are generated when the protons interact with matter. As the protons have larger energy than photons in conventional radiation therapy, there are generated neutrons with higher energy. This leads to that thick walls are needed to keep the neutron radiation from the treatment room away from the surroundings.

In this thesis proton beams with varying energy from 70 - 250 MeV have been dumped in a water phantom of (100x30x40)cm3 . The neutron fluence was recorded by the usrbin-card, and the energy spectrum was recorded by the usrbdx-card.

This simulations show that the penetration depths of neutrons are increasing with increasing proton beam energy.

The thesis was written in a project course at NTNU under supervision of Pål Erik Goa, in collaboration with Kristian Smeland Ytre-Hauge.

Files:

Fluka input file (change from .txt to .inp )

Flair file

Project report


2013:

Simulations of a Therapeutic Proton Beam with FLUKA Monte Carlo Code and Varian Eclipse Proton Planning Software - Master thesis work by Kine Johnsen

The purpose of this project has been to apply Monte Carlo software to simulate a proton beam resembling a therapeutic beam, and to study the interactions of this beam in phantoms of various design.

The Monte Carlo simulations were compared to results from Eclipse (a clinical dose planning system). The overall agreement between the two calculation methods were adequate, especially with respect to dose coverage within the defined target volume. However, when introducing different materials such as bone, air and aluminium into the geometry, the differences between the two methods became apparent and it illustrates the tentative limitations of a fast, clinical optimized, dose planning tool compared with a more accurate and detailed, hence tentatively slower, Monte Carlo simulation tool.

Kine looked into the source.f user routine in FLUKA in order to be able to define more complex beams than a simple pencil beam. Some example files for creating Spread-Out-Bragg-Peaks for protons and Fluka input files are available here:

source_kine.f

The thesis is available in pdf format here.


Biasing exercise from Workshop