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746 results on '"Verellen, D."'

3. ALANINE/EPR DOSIMETRY FOR ULTRA-HIGH DOSE RATE BEAMS USED FOR FLASH RADIOTHERAPY

Author

Marrale, M., primary, D’Oca, M.C., additional, Castronovo, E.R.A., additional, Collura, G., additional, Romeo, M., additional, Gasparini, A., additional, Vanreusel, V., additional, Verellen, D., additional, Reniers, B., additional, Felici, G., additional, Mariani, G., additional, Galante, F., additional, Pacitti, M., additional, Douralis, A., additional, Bass, G., additional, Subiel, A., additional, Pensavalle, J., additional, Milluzzo, G., additional, and Romano, F., additional

Published
2023
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11. Dosimetric characterization of an ultra-high dose rate beam for FLASH radiotherapy through alanine EPR dosimetry

Author

marrale maurizio, D'Oca Maria Cristina, Castronovo Electra, Collura Giorgio, Gasparini A, Vanreusel V, Verellen D, Felici G, Mariani G, Galante F, Pacitti M, Romano Francesco, marrale maurizio, D'Oca Maria Cristina, Castronovo Electra, Collura Giorgio, Gasparini A, Vanreusel V, Verellen D, Felici G, Mariani G, Galante F, Pacitti M, and Romano Francesco

Subjects
Alanine, FLASH radiotherapy, ultra-high dose rates, EPR dosimetry, Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin)
Abstract

Experimental evidence is growing, supporting the evidence of a considerable normal tissue sparing effect when treatments are delivered with dose rates much larger with respect to the conventional ones [1]. In particular, an increasing of the therapeutic window has been demonstrated for dose rates over 50 Gy/s, over a large variety of in-vivo experiments [2]. If confirmed, the ‘FLASH effect’ has the potential to re-shape the future of radiation treatments, with a significant impact on many oncology patients [3]. Ultra-high dose rate (UHDR) beams for FLASH radiotherapy present significant dosimetric challenges [4]. Ionization chambers are affected by ion recombination effects, although novel approaches for decreasing or correcting for this effect are being proposed [5]. Passive dosimeters, as radiochromic films and alanine [6], could be used for UHDR measurements, although dose determination is typically time consuming. Solid state detectors, such as diamond or Silicon Carbide (SiC) detectors, have been also recently investigated, as a valuable alternative for real-time measurements. In this work we analysed the response of alanine pellets to UHDR electron beams. Irradiations of alanine pellets with electron beams at 7 and 9 MeV, accelerated by a SIT-Sordina ElectronFlash Linac, at conventional and UHDR regimes have been carried out. Average dose rates up several hundreds of Gy/s were used for the experimental campaign, with instantaneous dose rate even more two orders of magnitudes larger. Indeed, pulse structure of the used accelerator is characterized by a pulse duration between 1-4 us and a frequency up to hundreds of Hz. The analysis of the depth dose profile performed by stacking alanine pellets along the electron beam direction allowed to evaluate whether a dependence on the dose rate is present for these UHDR beams. The experimental results were aided by computational analyses. The results will be presented and discussed in details.

Published
2022

25. OC-0505 Coverage with evidence development: generating real-life evidence on SBRT in Belgium.

Author

Lievens, Y., primary, Boesmans, L., additional, Engels, H., additional, Geets, X., additional, Jansen, N., additional, Janssens, S., additional, Lambrecht, M., additional, Remouchamps, V., additional, Roosens, S., additional, Stellamans, K., additional, Verellen, D., additional, Weltens, C., additional, Weytjens, R., additional, and Van Damme, N., additional

Published
2022
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34. SP-0690 How did the first wave affect medical physics practice in Europe? ESTRO survey

Author

Bertholet, J., primary, Aznar, M., additional, Garibaldi, C., additional, Thwaites, D., additional, Gershvevitsh, E., additional, Thorwarth, D., additional, Verellen, D., additional, Heijmen, B., additional, Hurkmans, C., additional, Muren, L., additional, Røe Redalen, K., additional, Siebert, F., additional, Schwarz, M., additional, Van Elmpt, W., additional, Georg, D., additional, Jornet, N., additional, and Clark, C., additional

Published
2021
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42. Reliability of ITV approach to varying treatment fraction time : a retrospective analysis based on 2D cine MR images

Author

Cusumano, Davide, Dhont, J., Boldrini, Luca, Chiloiro, Giuditta, Romano, A., Votta, C., Longo, S., Placidi, Lorenzo, Azario, Luigi, De Spirito, Marco, Verellen, D., and Valentini, Vincenzo

Subjects
lcsh:Medical physics. Medical radiology. Nuclear medicine, Internal target volume, Thorax, Intra-fraction motion management, lcsh:R895-920, medicine.medical_treatment, Radiotherapy Planning, Planning target volume, MR-guided radiotherapy, Radiosurgery, lcsh:RC254-282, 030218 nuclear medicine & medical imaging, Motion, 03 medical and health sciences, Computer-Assisted, 0302 clinical medicine, Retrospective analysis, Humans, Medicine, Radiology, Nuclear Medicine and imaging, Fraction (mathematics), Four-Dimensional Computed Tomography, Reliability (statistics), Retrospective Studies, Settore MED/36 - DIAGNOSTICA PER IMMAGINI E RADIOTERAPIA, Computer. Automation, Radiotherapy, business.industry, Research, Radiotherapy Planning, Computer-Assisted, Thoracic Neoplasms, lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens, Magnetic Resonance Imaging, Sagittal plane, Radiation therapy, medicine.anatomical_structure, Image-Guided, Oncology, Abdominal Neoplasms, 030220 oncology & carcinogenesis, Abdomen, Human medicine, Artifacts, business, Nuclear medicine, Radiotherapy, Image-Guided
Abstract

Background Internal Target Volume (ITV) is one of the most common strategies to passively manage tumour motion in Radiotherapy (RT). The reliability of this approach is based on the assumption that the tumour motion estimated during pre-treatment 4D Computed Tomography (CT) acquisition is representative of the motion during the whole RT treatment. With the introduction of Magnetic Resonance-guided RT (MRgRT), it has become possible to monitor tumour motion during the treatment and verify this assumption. Aim of this study was to investigate the reliability of the ITV approach with respect to the treatment fraction time (TFT) in abdominal and thoracic lesions. Methods A total of 12 thoracic and 15 abdominal lesions was analysed. Before treatment, a 10-phase 4DCT was acquired and ITV margins were estimated considering the envelope of the lesion contoured on the different 4DCT phases. All patients underwent MRgRT treatment in free-breathing, monitoring the tumour position on a sagittal plane with 4 frames per second (sec). ITV margins were projected on the tumour trajectory and the percentage of treatment time in which the tumour was inside the ITV (%TT) was measured to varying of TFT. The ITV approach was considered moderately reliable when %TT ≥ 90% and strongly reliable when %TT ≥ 95%. Additional ITV margins required to achieve %TT ≥ 95% were also calculated. Results In the analysed cohort of patients, ITV strategy can be considered strongly reliable only for lung lesions with TFT ≤ 7 min (min). The ITV strategy can be considered only moderately reliable for abdominal lesions, and additional margins are required to obtain %TT ≥ 95%. Considering a TFT ≤ 4 min, additional margins of 2 mm in cranio-caudal (CC) and 1 mm in antero-posterior (AP) are suggested for pancreatic lesions, 3 mm in CC and 2 mm in AP for renal and liver ones. Conclusions On the basis of the analysed cases, the ITV approach appears to be reliable in the thorax, while it results more challenging in the abdomen, due to the higher uncertainty in ITV definition and to the observed larger intra and inter-fraction motion variability. The addition of extra margins based on the TFT may represent a valid tool to compensate such limitations.

Published
2020

43. Characterisation and classification of oligometastatic disease: a European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer consensus recommendation

Author

Guckenberger, M., Guckenberger, M., Lievens, Y., Bouma, A.B., Collette, L., Dekker, A., deSouza, N.M., Dingemans, A.M.C., Fournier, B., Hurkmans, C., Lecouvet, F.E., Meattini, I., Romero, A.M., Ricardi, U., Russell, N.S., Schanne, D.H., Scorsetti, M., Tombal, B., Verellen, D., Verfaillie, C., Ost, P., Guckenberger, M., Guckenberger, M., Lievens, Y., Bouma, A.B., Collette, L., Dekker, A., deSouza, N.M., Dingemans, A.M.C., Fournier, B., Hurkmans, C., Lecouvet, F.E., Meattini, I., Romero, A.M., Ricardi, U., Russell, N.S., Schanne, D.H., Scorsetti, M., Tombal, B., Verellen, D., Verfaillie, C., and Ost, P.

Abstract

Oligometastatic disease has been proposed as an intermediate state between localised and systemically metastasised disease. In the absence of randomised phase 3 trials, early clinical studies show improved survival when radical local therapy is added to standard systemic therapy for oligometastatic disease. However, since no biomarker for the identification of patients with true oligometastatic disease is clinically available, the diagnosis of oligometastatic disease is based solely on imaging findings. A small number of metastases on imaging could represent different clinical scenarios, which are associated with different prognoses and might require different treatment strategies. 20 international experts including 19 members of the European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer OligoCare project developed a comprehensive system for characterisation and classification of oligometastatic disease. We first did a systematic review of the literature to identify inclusion and exclusion criteria of prospective interventional oligometastatic disease clinical trials. Next, we used a Delphi consensus process to select a total of 17 oligometastatic disease characterisation factors that should be assessed in all patients treated with radical local therapy for oligometastatic disease, both within and outside of clinical trials. Using a second round of the Delphi method, we established a decision tree for oligometastatic disease classification together with a nomenclature. We agreed oligometastatic disease as the overall umbrella term. A history of polymetastatic disease before diagnosis of oligometastatic disease was used as the criterion to differentiate between induced oligometastatic disease (previous history of polymetastatic disease) and genuine oligometastatic disease (no history of polymetastatic disease). We further subclassified genuine oligometastatic disease into repeat oligometastatic disease (previous

Published
2020

44. A novel procedure for determining the optimal: MLC. configuration parameters in treatment planning systems based on measurements with a Farmer chamber

Author

Universitat Rovira i Virgili, Saez, J; Hernandez, V; Goossens, J; De Kerf, G; Verellen, D, Universitat Rovira i Virgili, and Saez, J; Hernandez, V; Goossens, J; De Kerf, G; Verellen, D

Abstract

Modelling of the multi-leaf collimator (MLC) in treatment planning systems (TPS) is crucial for the dose calculation accuracy of intensity-modulated radiation therapy plans. However, no standardised methodology for their configuration exists to date. In this study we present a method that separates the effect of each dosimetric characteristic of the MLC, offering comprehensive equations for the determination of the configuration parameters used in the TPS model. The main advantage of the method is that it only requires prior knowledge of the nominal leaf width and is based on doses measured with a Farmer chamber, which is a very well established and robust methodology. Another significant advantage is the required time, since measuring the tests takes only about 30 minutes per energy. Firstly, we provide a theoretical general formalism in terms of the primary fluence constructed from the transmission map obtained from an MLC model for synchronous and asynchronous sweeping beams. Secondly, we apply the formalism to the RayStation TPS as a proof of concept and we derive analytical expressions that allow the determination of the configuration parameters (leaf tip width, tongue-and-groove width, x-position offset and MLC transmission) and describe how they intertwine. Finally, we apply the method to Varian's Millennium120 and HD120 MLCs in a TrueBeam linear accelerator for different energies and determine the optimal configuration parameters. The proposed procedure is much faster and streamlined than the typical trial-and-error methods and increases the accuracy of dose calculation in clinical plans. Additionally, the procedure can be useful for standardising the MLC configuration process and it exposes the limitations of the implemented MLC model, providing guidance for fu

Published
2020

46. SP-0205 B-QUATRO clinical audits: A Belgian success story?

Author

Vaandering, A., Batamuriza Almasi, A., Vermylen, A., Vanderstraeten, B., Weltens, C., Meunier, C., Verellen, D., Vandeputte, K., Van den Berghe, L., Van Dycke, M., Tomsej, M., Linthout, N., Deman, N., Van Houtte, P., Thysebaert, P., Cucchiaro, S., Derycke, S., Remouchamps, V., Bijdekerke, P., Scalliet, P., Vynckier, S., Lievens, Y., Vanhoutte, F., and Goemaere, E.

Published
2023
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