[Technique of complex mammary irradiation: Mono-isocentric 3D conformational radiotherapy and helical tomotherapy]. / Techniques d'irradiation mammaire complexe : radiothérapie conformationelle tridimensionnelle mono-isocentrique et nomothérapie hélicoïdale.

PURPOSE: To evaluate the dosimetric contribution of helical tomotherapy for breast cancers compared with conformal radiotherapy in mono-isocentric technique. PATIENTS AND METHOD: For 23 patients, the dosimetric results in mono-isocentric 3D conformational radiotherapy did not satisfy the constraints either of target volumes nor organs at risk. A prospective dosimetric comparison between mono-isocentric 3D conformational radiotherapy and helical tomotherapy was therefore carried out. RESULTS: The use of helical tomotherapy showed a benefit in these 23 patients, with either an improvement in the conformity index or homogeneity, but with an increase in low doses. Of the 23 patients, two had pectus excavatum, five had past thoracic irradiation and two required bilateral irradiation. The other 14 patients had a combination of morphology and/or indication of lymph node irradiation. For these patients, helical tomotherapy was therefore preferred to mono-isocentric 3D conformational radiotherapy. CONCLUSIONS: Tomotherapy appears to provide better homogeneity and tumour coverage. This technique of irradiation may be justified in the case of morphological situations such as pectus exavatum and in complex clinical situations. In other cases, conformal radiotherapy in mono-isocentric technique remains to be favoured.

[Potential indications for helical tomotherapy in breast cancers]. / Indications potentielles de la tomothérapie hélicoïdale dans les cancers du sein.

PURPOSE: To evaluate the dosimetric gain obtained in either the planning target volume or organs at risk coverage by the use of intensity-modulated radiation therapy in some particular postoperative breast cancers. PATIENTS AND METHOD: Prospective dosimetric comparison between monoisocentric conformal radiotherapy and intensity-modulated radiation therapy in nine patient files. RESULTS: Using intensity-modulated radiation therapy was shown to improve in each case, at least one conformity, homogeneity, and coverage index either for planning target volumes or for organs at risk. Intensity-modulated radiation therapy was therefore always chosen rather than conformal monoisocentric radiotherapy. CONCLUSIONS: Indications to retain intensity-modulated radiation therapy would consist of bilateral lesions, pectus excavatum, past thoracic irradiation (Hodgkin's disease) and complex volumes in obese or overweight patients.

[Conventional 2D and monoisocentric 3D techniques in breast and lymphatic irradiation: a dosimetric comparison]. / Techniques classique bidimensionnelle et mono-isocentrique tridimensionnelle dans l'irradiation du sein et des aires ganglionnaires : comparaison dosimétrique.

PURPOSE: The activity of our radiation oncology department mainly relies on breast pathology. Since July 2009, all the irradiations delivered simultaneously to the breast (CTV1), the surgical bed (CTV2), the internal mammary chain and the supra- and infraclavicular areas have been carried out using a mono-isocentric technique. This study aimed to compare dosimetric results between conventional 2D and mono-isocentric 3D techniques with or without optimization. PATIENTS AND METHODS: From January to August 2009, 20 patients with breast cancer in whom irradiation of the CTV1, CTV2, internal mammary chain and supra- and infraclavicular areas was retained, were included in a specific cohort. In each case, we have compared dosimetric results obtained with the conventional technique and with a mono-isocentric 3D technique, either with manual field in the field segmentation or with automatic segmentation (Oncentra Masterplan(®) from Nucletron(®), Optimizer(®) solution). Selected criteria were as follows: V95, V107 and mean dose (Dmean) to the target volumes, V20 and V30 to the ipsilateral lung, V35 and mean dose to the heart and maximal dose (Dmax) to the spinal cord. RESULTS: Supra- and infraclavicular areas irradiation was significantly better using the mono-isocentric 3D technique (V95 %: 89.7 % vs. 77.1 %; P=0.001) as well as dose homogeneity (Dmean: 46.3 Gy vs. 45.1 Gy; P=0.008). No statistical difference was observed for the other target volumes. Heart and spinal cord protection were better with the mono-isocentric 3D technique (respectively Dmean: 8.4Gy vs. 11.1 Gy; P<0.0001 and Dmax: 29.2 Gy vs. 35.8 Gy; P=0.0003). CONCLUSION: Mono-isocentric irradiation of the breast and lymphatic areas is a modern technique that benefits from imaging and computer progresses while being simple to carry out using standard planning system and linear accelerators. Mono-isocentric 3D irradiation with manual segmentation of the breast and the nodal areas provides a target volume irradiation comparing with conventional technique 2D and a better protection of the heart and of the spinal cord.

[Cartography and risk management in radiotherapy: A collaborative work of the department of radiotherapy and the department of quality and risk management at the Jean-Godinot Institute]. / Cartographie et gestion des risques en radiothérapie : un travail commun du département de radiothérapie et du département de la qualité et de la gestion des risques de l'institut Jean-Godinot.

PURPOSE: To deploy an inductive process for radiotherapy risk management in a regional cancer centre and to infer the actions required to solve the situations of criticality. METHODS: Close collaboration between the department of radiation oncology-biophysics and the department of quality and risk management in the same institution allowed to create a multiprofessional and multidisciplinary task force and to make the experience feedback easier. A preliminary risk analysis method was used to identify the generic dangers, the mapping of risks and the specification of the scales of criticality. This method helped to evaluate and to rate each apprehended event. Four scales have been defined: seriousness scale in five levels, likelihood scale in five classes, endeavour scale in four levels and criticality scale in three categories: acceptable (criticality 1) tolerable under control (criticality 2) and unacceptable (criticality 3). RESULTS: Fifty-seven level 1 dangerous situations linked to 78 scenarios of criticality acceptable, tolerable and unacceptable in 24, 44 and 10 cases respectively have been identified in the department of radiotherapy leading to carry out 28 risk reduction actions. CONCLUSIONS: The performed risk analysis offered an original frame for a collective thinking among the care providers and contributed to modify their mode of conceiving both security and radioprotection. The study allowed us to give a relevant answer to the High Authority of Health and the Authority of Nuclear Security demands either in terms of efficient management of the risks in radiotherapy or regarding the daily concerns of the caregivers.