Netherlands Commission on Radiation Dosimetry
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Nederlandse Commissie
voor Stralingsdosimetrie
Netherlands Commission on Radiation Dosimetry |
At present six subcommittees and one platform have been installed:
Advisory platform "Radiology and Nuclear Medicine"
This platform has been founded with the objective to provide support and advice for research projects in radiation dosimetry. At present the platform deals with the projects "Reference values diagnostic radiology" and "Registration of doses due to medical applications IMS".
Subcommittee "Implementation Monte Carlo calculations in Radiotherapy Treatment Planning"
The aim is to present a report containing guidelines for radiotherapy departments who intend to buy/use/customise a Monte Carlo treatment planning system for electron and photon therapy. Attention will be focused on commissioning, selection of treatments requiring Monte Carlo, variance reduction techniques, accelerator head modelling, patient modelling (conversion CT Hounsfield units), hardware requirements and the required knowledge to operate a MCTP system. An overview of the existing Monte Carlo dose engines and MCTP systems will be given.Members this NCS subcommittee: Ben Heijmen, Carlos De Wagter, Corine Van Vliet, Dennis Schaart, Jan Jansen, Marc Coghe, Milan Tomsej (secretary), Nick Reynaert (chairman), Steven van der Marck and Wiebe van der Zee.
Subcommittee "Quality control of low-photon-energy emitting seeds in Brachytherapy"
In the last few years the use of low-photon-energy emitting seeds has shown a vast increase especially for the treatment of localized prostate cancer with permanent Iodine or Palladium implants, this as well in the number of patients treated as well as in the number of institutions applying this treatment technique. On the other hand there are at present only few recommendations available concerning the quality assurance (QA) for this application.The subcommittee aims to prepare a report with guidelines for the QA for these radioactive sources, starting from an inventory of the current practice. Attention will also be focused on the calibration methods for these sources, the traceability of these methods and the problem concerning availability of a standard. The opportunity for organizing a visiting QA team will be investigated.
Members of this NCS subcommittee: Alex Rijnders (Europe Hospitals-Brussels, chairman), Sabine Bernard (UCL-St.Luc-Brussels, secretary), Marisol Debrabandere (UZ-Gasthuisberg-Leuven), Bénédicte Thissen (CHU-Liège), Cees Koedooder (AMC-Amsterdam), Rien Moerland (UMC-Utrecht), Arie van't Riet (RISO-Deventer), Tony Aalbers (NMi-Delft), Stefaan Vynckier (UCL-St.Luc-Brussels, representative from the NCS-board).
Subcommittee "Stereotactic radiotherapy: "Recommendations on dosimetry procedures and Quality Control"
In the Netherlands and Belgium a rapidly growing number of radiotherapy centers are being equipped for intracranial as well as extracranial stereotactic radiotherapy. Initially, stereotactic irradiation with a relatively high dose in a single fraction, called stereotactic radiosurgery (SRS), was based on the work of Leksell using a dedicated localization helmet and a dedicated Co-60 radiation source, the GammaKnife. Next there was the development of invasive and non-invasive frames for localization and treatment frames for fractionated stereotactic radiotherapy (fSRT) on (modified) linacs. More recently the development of SRT/SRS tends toward imaged guided frameless radiotherapy with dedicated linacs (Novalis and Cyberknife) mainly for intracranial lesions. The irradiation techniques evolved from arc beams using circular collimators via step and shoot micro MLC beams to stereotactic IMRT and robotic dose painting. Together with the interest of extracranial applications equipment for detection and automatic compensation of intra fractional tumor movements entered the field of SRT. Most treatment planning for fSRT/SRS is performed using a treatment planning system (TPS) that is part of the SRT/SRS hardware of a certain type and brand. Therefore the introduction of stereotactic radiotherapy in the clinic implies the acceptance, commissioning and QA of a stereotactic system as an entity. This includes the acceptance, commissioning and QA of the hardware (linac, mMLC, cone, frames, couch), software (TPS), imaging-system and systems for detection and automatic compensation of tumor movements. For the QC and guidelines of the various subsystems NCS reports are available. The increasing complexity of SRT/SRS and the increasing number of radiotherapy centers that offer this kind of SRT/SRS treatments justify an NCS report on stereotactic radiotherapy that covers the following topics:
- QC of mechanical equipment (immobilization, frames, linac, couch, pointers, …….)
- Recommendations on measurement of beam properties (dosimetry of small beams, recommendation on methods and specific detectors, reference beam data, output factors)
- Acceptance, commissioning and QC TPS. Referring to NCS QC TPS and supplementary specific QC for SRT.
- Supplementary QC CT-scanner, MRI, angiography and other imaging techniques, application of 4D-CT
- Acceptance, commissioning and QC of SRT imaging systems
- Proposal for End to End tests for SRT/SRS
- Recommendation on minimal QC (with tolerances)
- Recommendations on Treatment Verification and Registration and DICOM
- Recommendations on tests for detection and automated compensation of tumor movements
- Recommendations on determination of dose outside lesion (risk radiation induced tumors after treatment of benign lesions and functional neurological SRS).
- Recommendations and/or remarks on special issues related to intra- and extracranial SRT, body SRT, Cone beam, Image Guidance, frameless SRT..
Members of this NCS subcommittee: Frederic Dessy (Hopital de Jolimont, Haine St Paul), Stan Heukelom (Vrije Universiteit Medisch Centrum, Amsterdam), Hans Marijnissen (Erasmus MC, Rotterdam, chairman), An Nulens (UZ Gasthuisberg, Leuven), Geert Pittomvils (UZ, Gent), Esther Raaijmakers (Dr. B. Verbeeten Institute,Tilburg), Dirk Verellen (AZ-VUB, Brussel), Sandra Vieira (Erasmus MC, Rotterdam, secretary), Ben Heijmen (Erasmus MC, Rotterdam) representative from the NCS-board).
Subcommittee "Loodschorten" (Aprons): Protocols for personal dosimetry of workers wearing protective clothing
Dutch law (Besluit Stralingsbescherming) makes registration of effective dose to workers mandatory. In practice, readings from personal dosemeters (HP(10)) are recorded in the national database (NDRIS). If workers wear protective clothing during exposure the effective dose will be appreciably lower than HP(10) measured outside the apron. It is not unusual that individual workers of certain highly exposed categories apparently exceed the annual dose limit when dose is based on such measurements. Therefore, a few national dosimetry services apply a correction factor to the readings before registration. Others, however, do not. This makes comparison of registered dose results rather difficult. Correct and harmonized interpretation of measured dose values through application of standard protocols is highly desirable. An important condition is that such protocols should balance correctness and simplicity, as to prevent any fuss about their acceptance and application by fieldworkers, local radiological protection officers, dosimetry services and the government. The purpose of a research project that the NCS subcommittee carries out for the Ministry of Social Affairs and Employment is to compose protocols for proper personal dosimetry when protective clothing is worn. Questions to be answered are, for example, what is the current situation in the Netherlands and abroad; how can effective dose be estimated best from the dosemeter reading; which categories of workers/activities are concerned; under which circumstances is correction of dose values allowed and what correction factor should be applied; where should the dosemeter be worn. Recommendations resulting from the study will be presented in an NCS report, containing the following elements.
- Introduction: - Purpose (=harmonisation); - Scope (=for whom? for which conditions?)
- Methods for determination of HP(10): - Intercomparison of HP(10) measurements; - Corrections currently applied by dosimetry services (since when; within NL; elsewhere in EU; CONRAD activities)
- Inventory of correction methods: - Nature of radiological activities; - Types of procedure; - Characteristic types of equipment; - Influence of protective measures; - Wearing positions;- Shielding of the dosemeter
- Formulation of alternative protocols (discussion of their pros and cons)
- Code of Practice (recommended protocol)
Members of this NCS subcommittee: JanWillem van Dijk (NRG, Arnhem), Leo Ebben (Philips, Eindhoven), Yuri Franken (TUe, Eindhoven), Tom Grimbergen (VUmc, Amsterdam), as representatives from the four Dutch dosimetry services; Willy Hummel (KCL, Leeuwarden, NVKF representative), Pierre Kicken (ErasmusMC, Rotterdam, NVS representative), Frank Schultz (TU Delft, Delft), George Voorhout (UU-Diergeneeskunde, Utrecht, representative from the KNMvD), Hans Zoetelief (TU Delft, Delft, chairman and representative from the NCS board), Dirk Zweers (LUMC, Leiden, NVMBR representative and second representative from the NCS board).
To ensure its widespread acceptance and application, before issuing the proposed code of practice representatives of other related professional groups (NVvR, NVVC), united in the "NCS Platform voor Radiologie en Nucleaire Geneeskunde" will be consulted about the best choice from alternatives.
Subcommittee "Film Dosimetry"
Film is still the most popular 2D dosimeter which offers a unique spatial resolution. Radiographic film, however, is subject of controversy in literature and conflicting data have been reported. The essential point is that this film is oversensitive at low photon energies. When taking this point into account, a set of experimental conditions may be derived under which the accuracy of film dosimetry is acceptable. This goal justifies an NCS report that will cover the following topics on radiographic film:
- Principles of film dose response to ionizing radiation
- Effects of processing conditions
- Sensitometric curves and dynamic range
- Dose response dependence on depth and field size
- Dose response dependence on film orientation relative to beam direction
- value of film for single beam dosimetry
- value of film for mixed field dosimetry
- practical comparison between XV and EDR2
Parallel topics will deal with radiochromic film that might have the potential of gradually replacing radiographic film. Additional attention will be given to
- Film dosimetry for brachytherapy
- Film dosimetry for particle therapy
- Practical phantoms for film dosimetry
- Characteristics of film scanners
Members of this NCS subcommittee:
Jacco de Pooter (NMi-Delft), Carlos De Wagter (Ghent University Hospital, chairman), Stephen Kwa (UMC-Utrecht), Leen Paelink (Ghent University Hospital, secretary), Marleen Piessens (O. L. Vrouw Hospital, Aalst), Koen Tournel (University Hospital Brussels), Leo Van Battum (VUmc, Amsterdam), Peter van der Hulst (Groningen University Hospital), Ben Heijmen (Erasmus MC, Rotterdam) representative from the NCS-board).
Subcommittee: "Dosimetry Audit"
The goal of the committee is to design and administer an audit on absolute dosimetry in radiotherapy institutes in the Netherlands and Belgium. The audit will be based on the new NCS dosimetry protocol #18. In first instance, this audit will be limited to high energy photon beams. In the future an extension to high energy electron beams can be expected.The audit will focus on measurements of a 6 MV photon beam. Measurements of higher energies will be included when available. It is the intension to visit every institute in the Netherlands and Belgium. During the summer of 2008 a questionnaire will be distributed to collect necessary information. The audit itself is due to start in the fall of 2008.
Subcommittee Members
- Tony Aalbers, Advisor, Chairman NCS subcommittee Dosimetry Protocols
- Marjan Dwarswaard, Secretary MCA, Alkmaar
- Karen Feyen, AZ St. Maarten, Duffel (B)
- Joep Hermans, Maastro, Maastricht
- Erik Loeff, Erasmus MC, Rotterdam
- Jonathan Martens, Treasurer, Maastro, Maastricht
- Ester Peeters, MST, Enschede
- Thijs Perik, Chairman, NKI-AVL, Amsterdam
- Nicolette Planteydt, ZRTI, Vlissingen
- Leon de Prez, NMi, Delft
- Sander van 't Schip, Catherina, Eindhoven
- Francois Sergent, CHU, Charleroi (B)
- Frits Wittkämper, Advisor, NKI-AVL, Amsterdam
More information about audit and/or questionnaire can be found on www.nvkfm.nl.
