ISSN 2347-3487 1457 | Page January 29, 2015 Dosimetric comparison and time consuming evaluations for neoadjuvant 5- fields versus 7-fields Intensity-Modulated Radiation Therapy for locally advanced rectal cancer. Alessia Reali M.D., Gianluca Mortellaro M.D., Simona Allis M.D., Andrea Girardi Ph. D., Sara Bartoncini M.D., Silvia Maria Anglesio Ph. D., Edoardo Trevisiol Ph. D. and Maria Grazia Ruo Redda M.D. Department of Oncology, Radiation Oncology, University of Turin, S. Luigi Gonzaga Hospital, Orbassano, Turin, Italy Alessia Reali M.D. (corresponding Author) – alessia.reali@gmail.com Gianluca Mortellaro – gianlucamortellaro@virgilio.it Simona Allis M.D. – simona.allis@virgilio.it Andrea Girardi Ph.D.- girardi.and@gmail.com Sara Bartoncini M.D. – sara_bartoncini@hotmail.com Silvia Maria Anglesio Ph. D. – silvia.anglesio@gmail.com Edoardo Trevisiol Ph. D. – edoardo.trevisiol@unito.it Maria Grazia Ruo Redda M.D. - mariagrazia.ruoredda@unito.it ABSTRACT Preoperative – multidrug - chemoradiotherapy schedule (PCR) is proven to be the standard approach in patients with locally advanced rectal cancer (LARC). The main limiting factor of PCR delivery is severe acute gastrointestinal (GI) toxicity due to the small bowel irradiated volume. Compared to 3-dimensional conformal radiation therapy (3DCRT), intensity-modulated radiotherapy (IMRT) plans, with 7 or more fields, by highly conformal dose distributions, will minimize the dose received by small bowel, but required an increase in overall treatment time. The purpose of this study was to investigate if simple IMRT plans were comparable to conventional 7-fields IMRT in terms of dose distribution, with the advantage of reducing time delivery. Indexing terms/Keywords Rectal cancer; intensity-modulated radiotherapy; Bowel sparing; Planning and treatment times. Academic Discipline And Sub-Disciplines Radiation oncology. SUBJECT CLASSIFICATION Rectal cancer radiotherapy treatment. TYPE (METHOD/APPROACH) Retrospective analysis. Council for Innovative Research Peer Review Research Publishing System Journal: JOURNAL OF ADVANCES IN PHYSICS Vol.7, No.2 www.cirjap.com , japeditor@gmail.com