Potential benefits of using cardiac gated images to reduce the dose to the left anterior descending coronary during radiotherapy of left breast and internal mammary nodes; Benefice potentiel d'utilisation d'images obtenues avec gating cardiaque pour diminuer la dose d'irradiation au niveau de l'artere descendante coronaire gauche Almeida, C.E. de [Department of Radiation Oncology, Institut Curie, 26, rue d'Ulm, 75005 Paris (France)]; Laboratorio de Ciencias Radiologicas, Universidade de Estado de Rio de Janeiro - UERJ, Rua Sao Francisco Xavier 524, bl. F / s. T-030, 20.550-900, Maracana, Rio de Janeiro, RJ (Brazil)]; Fournier-Bidoz, N; Massabeau, C; Mazal, A; Campana, F; Fourquet, A; Kirova, Y M [Department of Radiation Oncology, Institut Curie, 26, rue d'Ulm, 75005 Paris (France)]; Canary, P C [Laboratorio de Ciencias Radiologicas, Universidade de Estado de Rio de Janeiro - UERJ, Rua Sao Francisco Xavier 524, bl. F / s. T-030, 20.550-900, Maracana, Rio de Janeiro, RJ (Brazil)]; Kuroki, I R [Clinica de Diagnostico por Imagem - CDPI, Rio de Janeiro, RJ (Brazil)] 62 RADIOLOGY AND NUCLEAR MEDICINE; CARCINOMAS; CORONARIES; CT-GUIDED RADIOTHERAPY; DOSIMETRY; HEART; IMAGE PROCESSING; IRRADIATION PROCEDURES; MAMMARY GLANDS; PATIENTS; RESPIRATION; SPATIAL DOSE DISTRIBUTIONS Purpose. - To assess the benefits of using cardiac gated images for treatment planning of breast and internal mammary nodes. Patients and methods. - Inspiration breath hold computed tomography (CT) series acquired at prospectively gated diastolic phase were used for planning. Three different techniques were compared. Technique A used tangents and an internal mammary nodes field covering the three first inter-rib spaces; technique B used an extended internal mammary nodes including part of the medial breast in junction with tangential fields; the 3. technique used helical tomo-therapy. For each technique, two treatment plans were performed: one plan (plan-01) where mean dose and V25 to the heart were considered for plan evaluation and a second plan (plan-02) where the irradiation of the left anterior descending artery was minimized. Results. - V{sub 25} to the heart was found to be less than 5% for all six plans. Mean doses to the heart were within 4.8 to 7.2 Gy. By attempting to lower the dose to the left anterior descending artery, heart D{sub mean} was decreased by 20-30% for the two techniques A and B while being unchanged for tomo-therapy. Regarding target coverage, there was no marked difference between plans where only heart dose was considered (plans-01) and plans where the left anterior descending artery dose was minimized (plans-02). When the left anterior descending artery dose was part of plan evaluation, D{sub mean} to the left anterior descending artery could be decreased by 24, 19 and 9% for techniques A, B and tomo-therapy respectively. The three techniques exposed segments of the left coronary to different levels of dose. Conclusion. - This study showed that evaluation of the dose to the left anterior descending artery coronary may change the treatment strategy. Cardiac gated images without IV contrast permitted a good visualization of the coronaries in order to optimize the dose on these structures. In addition to heart V{sub 25}, the dose to the coronaries should be included in prospective studies on radiotherapy related heart toxicity in association with all additional risk factors. (authors) Available from doi: http://dx.doi.org/10.1016/j.canrad.2011.07.244 France 2012-02-15 English; French Journal Article Journal Name: Cancer Radiotherapie; Journal Volume: 16; Journal Issue: 1; Other Information: 30 refs. Medium: X; Size: page(s) 44-51 https://doi.org/10.1016/J.CANRAD.2011.07.244 [] 1 16 Journal ID: ISSN 1278-3218; CODEN: CARAFC; TRN: FR1300590026671 INIS 2013-04-12 22067235