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

Accurate determination of the dose delivered to the tumour in external beam radiotherapy is of primary importance in clinical dosimetry. Until recently, the determination of absorbed dose under reference conditions has been based on the use of ionisation chambers calibrated in terms of air kerma as recommended in codes of practice, such as published in NCS Reports 2 and 5. Advances in radiation dosimetry concepts and the development of primary measurement standards based on absorbed dose to water over the last decades offer the possibility to calibrate ionisation chambers directly in terms of absorbed dose to water.

In NCS report 18 a Code of Practice is presented for the dosimetry in high energy photon and electron beams based on absorbed dose to water standards for 60Co reference beams. The CoP provides the concepts and methods to determine the absorbed dose in high energy photon and electron beams produced by medical linear accelerators and corresponds to the current clinical practice in Belgium and The Netherlands. The CoP covers the reference dosimetry in static, open photon beams with nominal energies between 1 and 25 MV and in static, open electron beams with nominal energies between 4 and 25 MeV produced by conventional linear accelerators. Treatment modalities as intensity modulated therapy (IMRT), stereotactic radiotherapy, robotic radiotherapy, helical tomotherapy, etc. are beyond the scope of this report.

The present CoP replaces the codes published in NCS reports 2 and 5 and recommends the use of a single, chamber dependent correction factor taking into account all effects dependent of the radiation beam quality. For photon beams these beam quality correction factors are based on experimental data, partly measured in selected clinical accelerator beams in Belgium and The Netherlands using a portable water calorimeter.

The physical concepts outlined in the Code represent a major simplification compared to the previous NCS Codes based on the concept of air kerma employing Bragg-Gray or Spencer-Attix cavity theory. This CoP uses updated information compared to the codes presented in TRS-398 and AAPM TG-51.

https://doi.org/10.25030/ncs-018

Please read the notification regarding ICRU-90.

 

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

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 sealded 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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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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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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