Monte Carlo Treatment Planning, An Introduction

The accuracy of dose calculation engines used for treatment planning in radiotherapy has been increasing continuously, going from calculations based on measurements, to pencil beam algorithms and superposition/convolution algorithms. Currently Monte Carlo dose calculation engines are being implemented into commercial treatment planning software as it is believed that the Monte Carlo method can provide an accuracy within 2-3%. It is important that clinical physicists have an insight into these systems, when introducing them into the clinic. This report tackles this acute problem by providing an extensive information on: 

- General purpose Monte Carlo codes for photon and electron dosimetry applications
- Modelling of particle transport
- Cross sections
- MCTP (Monte Carlo Treatment Planning) specific issues such as linac modelling, CT conversion, variance reduction techniques, scoring grids - Recent developments such as 4D applications and MCTP optimization

An important question is: is the added value of MCTP clinically relevant? To answer this question an extensive literature overview is provided. The main conclusion is that the MC method has an important added value when compared to pencil beam algorithms. More information is needed when comparing MC to superposition/convolution algorithms, although the first experiments (comparing accurate Monte Carlo dose calculation engines to superposition/convolution algorithms) demonstrate that the MC method will become very important in clinical treatment planning.

As the Monte Carlo method is by its nature very time consuming, a number of approximations have been included in the commercial Monte Carlo dose calculation engines for treatment planning. This leads to a calculation time reduction of several orders of magnitude. The impact on the dosimetrical accuracy is not well known yet. This report provides an overview of the existing Monte Carlo dose calculation engines, focussing on the applied approximations. An overview of the commercial MCTP systems that are already available or are currently being developed is given. As benchmarking remains equally important as for any other treatment planning system, a paragraph is devoted to quality control. Commercial MCTP systems can be benchmarked by measurements but also by comparison with accurate Monte Carlo dose calculation engines containing few approximations.

https://doi.org/10.25030/ncs-016

The NCS frequently publishes reports for fellow professionals in which recommendations are given for various quality control procedures or otherwise. The members of the NCS board and the members of the concerning subcommittee do not claim any authority exceeding that of their professional expertise. Responsibility on how the NCS recommendations are implemented lies with the user, taking into account the practice in his/her institution.


NCS Reports See all files

Quality Assurance of MRI for Radiotherapy

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Quality Assurance of Treatment Planning Systems

NCS 35, July 2022

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Code of Practice and recommendations for Total Body Irradiation and Total Skin Irradiation

NCS 34, February 2021

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Quality assurance of cone-beam CT for radiotherapy

NCS 32, February 2019

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Radiation Protection and Dosimetry of the Eye Lens

NCS 31, May 2018

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Code of Practice for Quality Assurance of Brachytherapy with Ir-192 Afterloaders

NCS 30, May 2018

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An on-site dosimetry audit for high-energy electron beams

NCS 29, October 2018

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National Audit of Quality Assurance for IMRT and VMAT

NCS 28, March 2018

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Quality Assurance for Tomotherapy Systems

NCS 27, April 2017

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Human Exposure to Ionising Radiation for Clinical and Research Purposes

NCS 26, May 2016

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Process Management and Quality Assurance for Intracranial Stereotactic Treatment

NCS 25, October 2015

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Code of Practice for the Quality Assurance and Control for Volumetric Modulated Arc Therapy

NCS 24, February 2015

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Audit of High-Energy Photon Beams in Belgian and Dutch Radiotherapy Departments

NCS 23, December 2013

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Code of Practice for the Quality Assurance and Control for Intensity Modulated Radiotherapy

NCS 22, June 2013

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Diagnostische referentieniveaus in Nederland

NCS 21, June 2012 (in Dutch with an English summary)

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Dosimetry and quality control of brachytherapy with low-energy photon sources (125I)

NCS 20, April 2012

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Code of practice for personal dosimetry of professionals wearing protective clothing during radiolog

NCS 19, October 2008

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Code of Practice for the Absorbed Dose Determination in High Energy Photon and Electron Beams

NCS 18, January 2008

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Dosimetrie in de Radiologie: Stralingsbelasting van de Patiënt en Werknemers

NCS 17, March 2007

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Monte Carlo Treatment Planning, An Introduction

NCS 16, June 2006

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Quality assurance of 3-D treatment planning systems for external photon and electron beams

NCS 15, March 2005

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Quality control of sealed beta sources in brachytherapy

NCS 14, August 2004

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Quality Control in Brachytherapy

NCS 13 November 2000

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Determination and use of scatter correction factors of megavoltage photon beams

NCS 12, March 1998, seel also NCS 15.
No revision required

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Quality Control (QC) of Simulators and CT scanners and some basic QC methods for Treatment Planning

NCS 11, September 1997, revision before 2020

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Dosimetry of low and medium energy X-rays

NCS 10, July 1997

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Quality control of medical linear accelerators: current practice and minimum requirements

NCS 9, August 1996, revision before 2020

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Kwaliteitscontrole van Medische Lineaire Versnellers, methoden voor kwaliteitscontrole

NCS 8, December 1995 (in Dutch), revision before 2020

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Recommendations for the calibration of Iridium-192 high dose rate sources

NCS 7, December 1994

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Dosimetric aspects of Mammography

NCS 6, March 1993

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Code of practice for the dosimetry of high-energy electron beams

NCS 5, December 1989

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Recommendations for dosimetry and quality control of radioactive sources used in brachytherapy

NCS 4 and 4a, February 1991 (in Dutch with an English summary)

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Proceedings of the Symposium on Thermoluminescence Dosimetry

NCS 3, October 1988

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Code of practice for the dosimetry of high-energy photon beams

NCS 2, December 1986

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Radiation dosimetry activities in the Netherlands

NCS 1, July 1986

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