Jean-Marc GALVAN                                Version française               

Maître de Conférences CPE

Site CPE Lyon
43, bd du 11 Novembre 1918
Bât. 308 – BP 2077
69616 Villeurbanne Cedex

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Localisation : CPE

Research activities

Department : Electronique

Group : Conception de Systèmes Hétérogènes

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Publications (last 5 years)

Articles Conférences invitées Communications

Articles (4)

Design and testing of a phantom and instrumented gynecological applicator based on GaN dosimeter for use in high dose rate brachytherapy quality assurance
P. Guiral, J. Ribouton, P. Jalade, R. Wang, J. Galvan, G. Lu, P. Pittet, A. Rivoire, L. Gindraux
Med. Phys. 43 2016 AbstractPurpose: High dose rate brachytherapy (HDR-BT) is widely used to treat gynecologic, anal, prostate, head, neck, and breast cancers. These treatments are typically administered in large dose per fraction (>5 Gy) and with high-gradient-dose-distributions, with serious consequences in case of a treatment delivery error (e.g., on dwell position and dwell time). Thus, quality assurance (QA) or quality control (QC) should be systematically and independently implemented. This paper describes the design and testing of a phantom and an instrumented gynecological applicator for pretreatment QA and in vivo QC, respectively. Methods: The authors have designed a HDR-BT phantom equipped with four GaN-based dosimeters. The authors have also instrumented a commercial multichannel HDR-BT gynecological applicator by rigid incorporation of four GaN-based dosimeters in four channels. Specific methods based on the four GaN dosimeter responses are proposed for accurate determination of dwell time and dwell position inside phantom or applicator. The phantom and the applicator have been tested for HDR-BT QA in routine over two different periods: 29 and 15 days, respectively. Measurements in dwell position and time are compared to the treatment plan. A modified position-time gamma index is used to monitor the quality of treatment delivery. Results: The HDR-BT phantom and the instrumented applicator have been used to determine more than 900 dwell positions over the different testing periods. The errors between the planned and measured dwell positions are 0.11 +/- 0.70 mm (1 sigma) and 0.01 +/- 0.42 mm (1 sigma), with the phantom and the applicator, respectively. The dwell time errors for these positions do not exhibit significant bias, with a standard deviation of less than 100 ms for both systems. The modified position-time gamma index sets a threshold, determining whether the treatment run passes or fails. The error detectability of their systems has been evaluated through tests on intentionally introduced error protocols. With a detection threshold of 0.7 mm, the error detection rate on dwell position is 22% at 0.5 mm, 96% at 1 mm, and 100% at and beyond 1.5 mm. On dwell time with a dwell time threshold of 0.1 s, it is 90% at 0.2 s and 100% at and beyond 0.3 s. Conclusions: The proposed HDR-BT phantom and instrumented applicator have been tested and their main characteristics have been evaluated. These systems perform unsupervised measurements and analysis without prior treatment plan information. They allow independent verification of dwell position and time with accuracy of measurements comparable with other similar systems reported in the literature. (C) 2016 American Association of Physicists in Medicine.       
Dosimetry systems based on Gallium Nitride probe for radiotherapy, brachytherapy and interventional radiology
P. Pittet, P. Jalade, J. Balosso, L. Gindraux, P. Guiral, R. Wang, A. Chaikh, A. Gaudu, J. Ribouton, J. Rousseau, J. Galvan, A. Rivoire, J. Giraud, G. Lu
IRBM 36, Issue: 2 , Special Issue: SI 92-100 2015 AbstractOur studies focus on dedicated dosimetry systems based on the Gallium Nitride (GaN) probe for Quality Assurance and patient safety in radiotherapy, brachytherapy and interventional radiology. The small size GaN transducer in the probe has high radioluminescence (RL) yield and rapid RL signal response for real time measurements. Preliminary prototypes of dedicated systems were tested in clinical conditions for external beam radiotherapy, brachytherapy and interventional radiology. The obtained pre-clinical results appear favorable and encouraging: in radiotherapy, GaN RL response has not significant dependence on the main influence parameters, excepted for the field size. In brachytherapy, using an instrumented phantom with integration of GaN probes allows real time verification of planned treatments. In interventional radiology, skin dose measurements using GaN probe based dosimeters show consistent results with those from a reference dosimeter. (C) 2015 Elsevier Masson SAS. All rights reserved.       
D. Ach, S. Briancon, G. Broze, F. Puel, A. Rivoire, J. Galvan, Y. Chevalier
Can. J. Chem. Eng. 93, Issue: 2, Special Issue: SI 183-191 2015 AbstractThe process of encapsulation by complex coacervation includes several steps that have been investigated in order to reach a better control over the whole process. This has been carried out for the encapsulation of linseed oil by the classical gelatin/acacia gum pair of coacervating polymers. Fabrication of an oil-in-water emulsion is the first step that has been studied so as to reach a definite picture of the emulsification process under intermediate flow regime in a stirred unbaffled vessel. The classical scheme of oil droplet break-up by turbulent eddies in the turbulent inertial regime gave a fair agreement with the experiments and can be used as a possible framework for a process scale-up. Polynuclear microcapsules containing several oil droplets have been obtained during the deposition of the coacervate onto the surface of oil droplets. According to the emulsification conditions and microparticles growth caused by multiple droplets encapsulation, microcapsules of approximate to 130 mu m were produced. A video probe immersed in the stirred vessel allowed an in situ monitoring of the successive events taking place as acid was added into the medium. This technique allows dynamic observations of microcapsules formation. These observations confirmed the deposition of coacervate droplets around oil drops and clearly showed that the formation of coacervate particles and their deposition onto oil droplets were successive events.       
Friction of 316L stainless steel on soft-tissue-like poly(vinyl alcohol) hydrogel in physiological liquid
D. Ach, S. Briancon, G. Broze, F. Puel, A. Rivoire, J. Galvan, Y. Chevalier
Tribol. Int. 82, Part: B Special Issue: SI 407-414 2015 AbstractThe tribological behavior of medical SUS316L stainless steel on soft-tissue-like poly(vinyl alcohol) (PVA) hydrogel with and without dimethyl sulfoxide (DMSO) was investigated in physiological condition. In lower sliding velocity region, the maximum friction coefficient (mu(max)) is observed at certain velocity due to the adsorption of polymer chains on SUS316L. The presence of plasma proteins into liquid largely reduced mu(max) of SUS316L. Among plasma proteins tested, we found that mostly Human Serum Albumin was adsorbed on SUS316L, inhibiting the adsorption of PVA chains onto SUS316L. (C) 2014 Elsevier Ltd. All rights reserved.       

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