[Quality assurance of radiotherapy in clinical research]. / Assurance qualité de la radiothérapie en recherche clinique.

Quality assurance for radiotherapy of a clinical trial is an important step from the design of the clinical trial. A precise definition of quality assurance must be given in detail in the clinical protocol of the clinical trial. By its implementation, quality assurance allows a homogeneity of the clinical trial, which can lead to a reduction of the biases of results interpretation for the clinical trial. The complexity of the radiotherapy to be carried out within the framework of the clinical trial can induce a gradation for the radiotherapy quality assurance program of the trial. However, the following steps are always present and must be described either directly in the clinical protocol or in a specific chapter, radiotherapy quality assurance, of the clinical protocol. The detailed characteristics of the medical imaging required to prepare for the treatment, the delineation of the targets and organs at risk, the requirements related to the planning, the treatment itself, possibly including the positioning repositioning control images, of the patient. For the delineation and planning stages, it is common to set up benchmarking based on test cases (dummy run, dry run). Their validation makes it possible for the center to get credentials for the clinical trial. Some trials can provide for an additional quality assurance point, such End-to-End test for which the investigating center must carry out, according to the clinical protocol, the preparation, the planning, the treatment on an anthropomorphic test object containing models of targets, organs at risk as well as dosimeters. Quality assurance of radiotherapy in clinical research is an essential part to be taken into account from the design of the clinical study. The commitment of the investigating center in terms of human and material resources in compliance with the protocol and in the quality assurance of the trial constitute a guarantee of limitation of the biases for the study and its interpretation, facilitating the answer of the scientific question asked by the trial.

[Clinical research in radiation oncology: how to move from the laboratory to the patient?] / Recherche clinique en oncologie radiothérapie : comment passer du laboratoire au patient ?

Translational research in radiation oncology is undergoing intense development. An increasingly rapid transfer is taking place from the laboratory to the patients, both in the selection of patients who can benefit from radiotherapy and in the development of innovative irradiation strategies or the development of combinations with drugs. Accelerating the passage of discoveries from the laboratory to the clinic represents the ideal of any translational research program but requires taking into account the multiple obstacles that can slow this progress. The ambition of the RadioTransNet network, a project to structure preclinical research in radiation oncology in France, is precisely to promote scientific and clinical interactions at the interface of radiotherapy and radiobiology, in its preclinical positioning, in order to identify priorities for strategic research dedicated to innovation in radiotherapy. The multidisciplinary radiotherapy teams with experts in biology, medicine, medical physics, mathematics and engineering sciences are able to meet these new challenges which will allow these advances to be made available to patients as quickly as possible.

Dose constraints for moderate hypofractionated radiotherapy for prostate cancer: The French genito-urinary group (GETUG) recommendations.

Considering recent phase III trials results, moderate hypofractionated radiotherapy can be considered as a standard treatment for low and intermediate risk prostate cancer management. This assessment call for a framework allowing homogeneous and reproducible practices in the different centers using this radiotherapy schedule. The French Genito-Urinary Group (GETUG) provides here recommendations for daily practice of moderate hypofractionated radiotherapy for prostate cancer, with indications, dose, fractionation, pre-treatment planning, volume of interest delineation (target volume and organs at risk) and margins, dose constraints and radiotherapy techniques.

[Intensity modulated radiation therapy: analysis of patient specific quality control results, experience of René-Gauducheau Centre]. / Radiothérapie conformationnelle avec modulation d'intensité: analyse des résultats des contrôles précliniques, expérience du centre René-Gauducheau.

PURPOSE: Systematic verifications of patient's specific intensity-modulated radiation treatments are usually performed with absolute and relative measurements. The results constitute a database which allows the identification of potential systematic errors. MATERIAL AND METHODS: We analyzed 1270 beams distributed in 232 treatment plans. Step-and-shoot intensity-modulated radiation treatments were performed with a Clinac (6 and 23 MV) and sliding window intensity-modulated radiation treatments with a Novalis (6 MV). RESULTS: The distributions obtained do not show systematic error and all the control meet specified tolerances. CONCLUSION: These results allow us to reduce controls specific patients for treatments performed under identical conditions (location, optimization and segmentation parameters of treatment planning system, etc.).

[Use of IGRT for prostate cancers (OBI-CBCT Varian, ExacTrac BrainLAB and MVCT TomoTherapy)]. / Quelle radiothérapie guidée par l'image pour quels patients? Expérience concomitante de l'utilisation de trois dispositifs d'imagerie de repositionnement dans le cas du cancer de la prostate.

INTRODUCTION: The aim of this work was to report the experience of image-guided radiotherapy at the CLCC Nantes-Atlantique using three repositioning imaging devices, the ExacTrac (BrainLAB), the OBI-CBCT (Varian) and the MVCT (Tomotherapy Inc), in the case of prostate external radiotherapy. MATERIAL AND METHODS: For each linac and its imaging device, a treatment plan was described. Moreover, studies concerning calculated shifts after imaging sessions were achieved. Using ExacTrac, for eight patients, a study compared daily shifts based on bony anatomy or on implanted markers. Considering mean values of displacements over a course of radiotherapy, dosimetric impact was evaluated. With the OBI-CBCT, two imaging modalities were used, kV-kV (0 degrees and 270 degrees ) and CBCT. Up to now, whatever the images, displacements were calculated using the bony anatomy. For both modalities and for 26 patients, shifts were compared. Since the beginning of the Tomotherapy HiArt use, MVCT was performed for each session of each patient. For 12 patients, mean displacements were calculated after five fractions. Then the deviations to those values were calculated. This was done to show the relevance of daily MVCT. RESULTS AND CONCLUSION: This work allows us to report the use of three repositioning imaging devices in the radiotherapy department. At least they provide an efficient positioning tool. And they let us see the future radiotherapy which would probably be the dose-guided radiotherapy.