Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2003
The OPERA project is dedicated to neutrino oscillation search in the CNGS neutrino beam from CERN... more The OPERA project is dedicated to neutrino oscillation search in the CNGS neutrino beam from CERN to Gran Sasso (Experimental Proposal, CERN/SPSC 2000-028, SPSC/P318, LNGS P25/2000. The experiment is designed to characterize the interactions of n t resulting of the n m -n t oscillation.
2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)
A 2nd generation high performance small animal PET scanner, called ClearPET™, has been designed a... more A 2nd generation high performance small animal PET scanner, called ClearPET™, has been designed and a first prototype is built by working groups of the Crystal Clear Collaboration (CCC). In order to achieve high sensitivity and maintain good uniform spatial resolution over the field of view in high resolution PET systems, it is necessary to extract the depth of interaction (DOI) information and correct for spatial degradation. The design of the first ClearPET™ Demonstrator based on the use of the multi-anode photomultiplier tube (Hamamatsu R7600-M64) and a LSO/LuYAP phoswich matrix. The two crystal layers of 8*8 crystals (2*2*10 mm3) are stacked on each other and mounted without light guide as one to one on the PMT. A unit of four PMTs arranged in-line represents one of 20 sectors of the ring design. The opening diameter of the crystal ring is 137 mm, the axial detector length is 110 mm. The PMT pulses are digitized by free-running ADCs and digital data processing determines the gamma energy, the phoswich layer and even the pulse arrival time. Single gamma interactions are recorded and coincidences are found by software. The gantry allows rotation of the detector modules around the field of view. The measurements have been done using the first LSO/LuYAP detector cassettes.
The ClearPET™ Neuro is the first full ring scanner within the Crystal Clear Collaboration (CCC). ... more The ClearPET™ Neuro is the first full ring scanner within the Crystal Clear Collaboration (CCC). It consists of 80 detector modules allocated to 20 cassettes. LSO and LuYAP:Ce crystals in phoswich configuration in combination with position sensitive photomultiplier tubes are used to achieve high sensitivity and realize the acquisition of the depth of interaction (DOI) information. The complete system has
ABSTRACT The control of VMAT treatments is a key issue in the Quality Assurance process. Current ... more ABSTRACT The control of VMAT treatments is a key issue in the Quality Assurance process. Current solutions are often cumbersome to implement and unsuitable for routine use. An innovative solution is proposed by the Dosimetry Check software (Math- Resolutions) allowing both to control pre-treatment as well as socalled transit dosimetry using the portal imager. Here we present the implementation and the evaluation of the software to control VMAT treatments of prostate.Material and methodsAcquisition where made on a Clinac 2100C equipped with an IaS500. Images, acquired in continuous mode (@60 frames/rotation), CT scanner and associated structures and 3D dose matrix are imported in Dosimetry Check. Fluence matrix in air is obtained by filtered backprojection. The dose volume in the patient is calculated with Pencil Beam algorithm. Analysis is based on the comparison of point dose, dose profiles, and dose distributions in 2D and 3D. The calculation of Dose Volume Histogram and Gamma Index is also available.Results and conclusionThe study focuses on 10 cases of prostate cancer treated in VMAT according to simultaneous integrated boost. The deviation of measured dose at the isocenter in pre-treatment and in transit mode is of the order of −4.0%(±1.3%) and 4.9%(±4.1%) respectively. These results improve significantly when corrected by the acquisition of an integrated image: +1.4%(±0.7%) in pre-treatment and −1.1%(±0.7%) in transit mode.Dosimetry Check software is a suitable tool to do pre-treatment control and in vivo dosimetry. The first results are satisfactory and we wish to test it on other sites, but weaknesses of Pencil Beam algorithm have to be taken into account.
ABSTRACT The In vivo dosimetry which is now mandatory in France, is a part of the process of Qual... more ABSTRACT The In vivo dosimetry which is now mandatory in France, is a part of the process of Quality Assurance (QA) of radiotherapy. It ensures that the dose delivered during a treatment corresponds to that planned. The purpose of this study is to test and evaluate a new in vivo dosimetry 3D software DosimetryCheck (MathResolutions) by portal imaging (EPID) for the treatment of breast cancer.Materials and methodsWe performed measurements on thirty patients, divided into three groups:–Group 1: an integrated image of each treatment beam is made during the first three sessions, to estimate the standard deviation of the method. The dose measured is compared to the calculated by the TPS (Eclipse) at different points.–Group 2: an integrated image of each treatment beam is made at the first session and compared with a measurement made at the second session by Mosfet detectors (Arplay Medical) positioned at the entrance beam.–Group 3: an integrated image of each treatment beam is performed during all sessions to try to detect errors positioning by compare the measured deviation and matching with the DRR.ResultsThe deviation of the measured dose to the calculated is around 3.6% (±1.5%). Both measurement methods of in vivo by Mosfet and DosimetryChech have a deviation of 2.8% (±2.1%).Taking a tolerance of 0.5 cm on the error positioning, a concordance rate of 73% was observed for deviation dose >5%.Conclusion This method of in vivo dosimetry is in agreement with those performed by conventional detectors.She has two advantages: on the one hand do not require additional set up during sessions, and another allows to highlight repositioning errors.However, the calculation algorithm used (Pencil Beam) don't take into account of heterogeneity so it made systematic differences of dose.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2003
The OPERA project is dedicated to neutrino oscillation search in the CNGS neutrino beam from CERN... more The OPERA project is dedicated to neutrino oscillation search in the CNGS neutrino beam from CERN to Gran Sasso (Experimental Proposal, CERN/SPSC 2000-028, SPSC/P318, LNGS P25/2000. The experiment is designed to characterize the interactions of n t resulting of the n m -n t oscillation.
2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)
A 2nd generation high performance small animal PET scanner, called ClearPET™, has been designed a... more A 2nd generation high performance small animal PET scanner, called ClearPET™, has been designed and a first prototype is built by working groups of the Crystal Clear Collaboration (CCC). In order to achieve high sensitivity and maintain good uniform spatial resolution over the field of view in high resolution PET systems, it is necessary to extract the depth of interaction (DOI) information and correct for spatial degradation. The design of the first ClearPET™ Demonstrator based on the use of the multi-anode photomultiplier tube (Hamamatsu R7600-M64) and a LSO/LuYAP phoswich matrix. The two crystal layers of 8*8 crystals (2*2*10 mm3) are stacked on each other and mounted without light guide as one to one on the PMT. A unit of four PMTs arranged in-line represents one of 20 sectors of the ring design. The opening diameter of the crystal ring is 137 mm, the axial detector length is 110 mm. The PMT pulses are digitized by free-running ADCs and digital data processing determines the gamma energy, the phoswich layer and even the pulse arrival time. Single gamma interactions are recorded and coincidences are found by software. The gantry allows rotation of the detector modules around the field of view. The measurements have been done using the first LSO/LuYAP detector cassettes.
The ClearPET™ Neuro is the first full ring scanner within the Crystal Clear Collaboration (CCC). ... more The ClearPET™ Neuro is the first full ring scanner within the Crystal Clear Collaboration (CCC). It consists of 80 detector modules allocated to 20 cassettes. LSO and LuYAP:Ce crystals in phoswich configuration in combination with position sensitive photomultiplier tubes are used to achieve high sensitivity and realize the acquisition of the depth of interaction (DOI) information. The complete system has
ABSTRACT The control of VMAT treatments is a key issue in the Quality Assurance process. Current ... more ABSTRACT The control of VMAT treatments is a key issue in the Quality Assurance process. Current solutions are often cumbersome to implement and unsuitable for routine use. An innovative solution is proposed by the Dosimetry Check software (Math- Resolutions) allowing both to control pre-treatment as well as socalled transit dosimetry using the portal imager. Here we present the implementation and the evaluation of the software to control VMAT treatments of prostate.Material and methodsAcquisition where made on a Clinac 2100C equipped with an IaS500. Images, acquired in continuous mode (@60 frames/rotation), CT scanner and associated structures and 3D dose matrix are imported in Dosimetry Check. Fluence matrix in air is obtained by filtered backprojection. The dose volume in the patient is calculated with Pencil Beam algorithm. Analysis is based on the comparison of point dose, dose profiles, and dose distributions in 2D and 3D. The calculation of Dose Volume Histogram and Gamma Index is also available.Results and conclusionThe study focuses on 10 cases of prostate cancer treated in VMAT according to simultaneous integrated boost. The deviation of measured dose at the isocenter in pre-treatment and in transit mode is of the order of −4.0%(±1.3%) and 4.9%(±4.1%) respectively. These results improve significantly when corrected by the acquisition of an integrated image: +1.4%(±0.7%) in pre-treatment and −1.1%(±0.7%) in transit mode.Dosimetry Check software is a suitable tool to do pre-treatment control and in vivo dosimetry. The first results are satisfactory and we wish to test it on other sites, but weaknesses of Pencil Beam algorithm have to be taken into account.
ABSTRACT The In vivo dosimetry which is now mandatory in France, is a part of the process of Qual... more ABSTRACT The In vivo dosimetry which is now mandatory in France, is a part of the process of Quality Assurance (QA) of radiotherapy. It ensures that the dose delivered during a treatment corresponds to that planned. The purpose of this study is to test and evaluate a new in vivo dosimetry 3D software DosimetryCheck (MathResolutions) by portal imaging (EPID) for the treatment of breast cancer.Materials and methodsWe performed measurements on thirty patients, divided into three groups:–Group 1: an integrated image of each treatment beam is made during the first three sessions, to estimate the standard deviation of the method. The dose measured is compared to the calculated by the TPS (Eclipse) at different points.–Group 2: an integrated image of each treatment beam is made at the first session and compared with a measurement made at the second session by Mosfet detectors (Arplay Medical) positioned at the entrance beam.–Group 3: an integrated image of each treatment beam is performed during all sessions to try to detect errors positioning by compare the measured deviation and matching with the DRR.ResultsThe deviation of the measured dose to the calculated is around 3.6% (±1.5%). Both measurement methods of in vivo by Mosfet and DosimetryChech have a deviation of 2.8% (±2.1%).Taking a tolerance of 0.5 cm on the error positioning, a concordance rate of 73% was observed for deviation dose >5%.Conclusion This method of in vivo dosimetry is in agreement with those performed by conventional detectors.She has two advantages: on the one hand do not require additional set up during sessions, and another allows to highlight repositioning errors.However, the calculation algorithm used (Pencil Beam) don't take into account of heterogeneity so it made systematic differences of dose.
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Papers by G. Largeron