J. Verstraete - Academia.edu (original) (raw)
Papers by J. Verstraete
Radiotherapy and Oncology, 2012
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Acta Oncologica, 2015
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Radiotherapy and Oncology, 2013
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Radiotherapy and Oncology, 2014
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Radiotherapy and Oncology, 2009
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Radiotherapy and Oncology, 2013
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Radiation Oncology, 2007
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Radiotherapy and Oncology, 2011
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Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology, 2004
The aim of this work is to set-up mailed entrance in vivo dosimetry by means of thermoluminescenc... more The aim of this work is to set-up mailed entrance in vivo dosimetry by means of thermoluminescence dosimeters (TLDs) in the form of LiF powder in order to assess the overall accuracy of patient treatment delivery by comparing the doses delivered to patients with the doses calculated by the treatment planning system (TPS) in different institutions. Two millimeter thick copper (for 6 MV photon beams) and 1.3 mm thick aluminium (for (60)Co gamma beams) build-up caps are developed. The characteristics of these build-up caps are tested by phantom measurements: the response of the TLD inside the build-up cap is compared to the ionisation chamber (IC) signal in the same irradiation conditions. A pilot study using the copper build-up cap is performed on 8 patients, treated with a 6 MV photon beam at the radiotherapy department of the University Hospital of Leuven. Additionally, a first run of mailed entrance in vivo dosimetry is performed by 18 radiotherapy centres in Europe. For 80 differe...
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Journal of Radiotherapy …, 2007
Methods: First, we conducted a retrospective study in ten patients. Skin marks were used for set-... more Methods: First, we conducted a retrospective study in ten patients. Skin marks were used for set-up and the position was verified and corrected at the start of treatment by portal imaging. Second, we analysed the implementation of a more rigorous verification and correction ...
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Radiotherapy and Oncology, 2002
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Journal of Radiotherapy in Practice
Background and purpose: Due to the increased complexity of the radiotherapy process in recent yea... more Background and purpose: Due to the increased complexity of the radiotherapy process in recent years, many QA procedures have been introduced to improve the quality of the treatment preparation and the treatment delivery. Most of these procedures give no direct information on the efficiency of the overall process in the radiotherapy department. It is quite evident that the frequency of errors will affect the efficiency of the process (for instance manpower to solve the detected problems), but also affect more generally the patients' experience.Material and methods: To make some objective assessment of the erroneous entries in the process of radiotherapy, a pilot study was initiated to report all problems during a period of 2 months on a dedicated QA form. By registration of these errors, the QA group could trace the main sources of the decrease in efficiency and increased waiting time for patients.Results and conclusions: For 46% of the patients during the two months at least one...
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Radiotherapy and Oncology
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Radiotherapy and Oncology, 1991
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Radiotherapy and Oncology, 1996
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Radiotherapy and Oncology, 2001
Although intensity modulated radiation therapy is characterized by three-dimensional dose distrib... more Although intensity modulated radiation therapy is characterized by three-dimensional dose distributions which are often superior to those obtained with conventional treatment plans, its routine clinical implementation is partially held back by the complexity of the beam verification. This is even more so when a dynamic multileaf collimator (dMLC) is used instead of a segmented beam delivery. We have therefore investigated the possibility of using a commercially available, liquid-filled electronic portal imaging device (EPID) for the pre-treatment quality assurance of dynamically delivered dose distributions. A special acquisition mode was developed to optimize the image acquisition speed for dosimetry with the liquid-filled EPID. We investigated the accuracy of this mode for 6 and 18 MV photon beams through comparison with film and ion chamber measurements. The impact of leaf speed and pulse rate fluctuations was quantified by means of dMLC plans especially designed for this purpose. Other factors influencing the accuracy of the dosimetry (e.g. the need for build-up, remanence of the ion concentration in the liquid and bulging of the liquid at non-zero gantry angles) were studied as well. We finally compared dosimetric EPID images with the corresponding image prediction delivered without a patient in the beam. The dosimetric accuracy of the measured dose distribution is approximately 2% with respect to film and ion chamber measurements. The accuracy declines when leaf speed is increased beyond 2 cm/s, but is fairly insensitive to accelerator pulse rate fluctuations. The memory effect is found to be of no clinical relevance. When comparing the acquired and expected distributions, an overall agreement of 3% can be obtained, except at areas of steep dose gradients where slight positional shifts are translated into large errors. Accurate dosimetric images of intensity modulated beam profiles delivered with a dMLC can be obtained with a commercially available, liquid-filled EPID. The developed acquisition mode is especially suited for fast and accurate pre-treatment verification of the intensity modulated fields.
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Medical Physics, 2006
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Radiotherapy and Oncology, 2011
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Radiotherapy and Oncology, 2012
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Acta Oncologica, 2015
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Radiotherapy and Oncology, 2013
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Radiotherapy and Oncology, 2014
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Radiotherapy and Oncology, 2009
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Radiotherapy and Oncology, 2013
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Radiation Oncology, 2007
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Radiotherapy and Oncology, 2011
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Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology, 2004
The aim of this work is to set-up mailed entrance in vivo dosimetry by means of thermoluminescenc... more The aim of this work is to set-up mailed entrance in vivo dosimetry by means of thermoluminescence dosimeters (TLDs) in the form of LiF powder in order to assess the overall accuracy of patient treatment delivery by comparing the doses delivered to patients with the doses calculated by the treatment planning system (TPS) in different institutions. Two millimeter thick copper (for 6 MV photon beams) and 1.3 mm thick aluminium (for (60)Co gamma beams) build-up caps are developed. The characteristics of these build-up caps are tested by phantom measurements: the response of the TLD inside the build-up cap is compared to the ionisation chamber (IC) signal in the same irradiation conditions. A pilot study using the copper build-up cap is performed on 8 patients, treated with a 6 MV photon beam at the radiotherapy department of the University Hospital of Leuven. Additionally, a first run of mailed entrance in vivo dosimetry is performed by 18 radiotherapy centres in Europe. For 80 differe...
Bookmarks Related papers MentionsView impact
Journal of Radiotherapy …, 2007
Methods: First, we conducted a retrospective study in ten patients. Skin marks were used for set-... more Methods: First, we conducted a retrospective study in ten patients. Skin marks were used for set-up and the position was verified and corrected at the start of treatment by portal imaging. Second, we analysed the implementation of a more rigorous verification and correction ...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Radiotherapy and Oncology, 2002
Bookmarks Related papers MentionsView impact
Journal of Radiotherapy in Practice
Background and purpose: Due to the increased complexity of the radiotherapy process in recent yea... more Background and purpose: Due to the increased complexity of the radiotherapy process in recent years, many QA procedures have been introduced to improve the quality of the treatment preparation and the treatment delivery. Most of these procedures give no direct information on the efficiency of the overall process in the radiotherapy department. It is quite evident that the frequency of errors will affect the efficiency of the process (for instance manpower to solve the detected problems), but also affect more generally the patients' experience.Material and methods: To make some objective assessment of the erroneous entries in the process of radiotherapy, a pilot study was initiated to report all problems during a period of 2 months on a dedicated QA form. By registration of these errors, the QA group could trace the main sources of the decrease in efficiency and increased waiting time for patients.Results and conclusions: For 46% of the patients during the two months at least one...
Bookmarks Related papers MentionsView impact
Radiotherapy and Oncology
Bookmarks Related papers MentionsView impact
Radiotherapy and Oncology, 1991
Bookmarks Related papers MentionsView impact
Radiotherapy and Oncology, 1996
Bookmarks Related papers MentionsView impact
Radiotherapy and Oncology, 2001
Although intensity modulated radiation therapy is characterized by three-dimensional dose distrib... more Although intensity modulated radiation therapy is characterized by three-dimensional dose distributions which are often superior to those obtained with conventional treatment plans, its routine clinical implementation is partially held back by the complexity of the beam verification. This is even more so when a dynamic multileaf collimator (dMLC) is used instead of a segmented beam delivery. We have therefore investigated the possibility of using a commercially available, liquid-filled electronic portal imaging device (EPID) for the pre-treatment quality assurance of dynamically delivered dose distributions. A special acquisition mode was developed to optimize the image acquisition speed for dosimetry with the liquid-filled EPID. We investigated the accuracy of this mode for 6 and 18 MV photon beams through comparison with film and ion chamber measurements. The impact of leaf speed and pulse rate fluctuations was quantified by means of dMLC plans especially designed for this purpose. Other factors influencing the accuracy of the dosimetry (e.g. the need for build-up, remanence of the ion concentration in the liquid and bulging of the liquid at non-zero gantry angles) were studied as well. We finally compared dosimetric EPID images with the corresponding image prediction delivered without a patient in the beam. The dosimetric accuracy of the measured dose distribution is approximately 2% with respect to film and ion chamber measurements. The accuracy declines when leaf speed is increased beyond 2 cm/s, but is fairly insensitive to accelerator pulse rate fluctuations. The memory effect is found to be of no clinical relevance. When comparing the acquired and expected distributions, an overall agreement of 3% can be obtained, except at areas of steep dose gradients where slight positional shifts are translated into large errors. Accurate dosimetric images of intensity modulated beam profiles delivered with a dMLC can be obtained with a commercially available, liquid-filled EPID. The developed acquisition mode is especially suited for fast and accurate pre-treatment verification of the intensity modulated fields.
Bookmarks Related papers MentionsView impact
Medical Physics, 2006
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Radiotherapy and Oncology, 2011
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