Authors : Khaled Saeed Sallam; Sohir Mahmoud El Kholy; Mostafa Aly El Naggar; Fatma Ismael Nasr; Walla Taman

Volume/Issue : 2nd ICTSA-2022

Google Scholar : https://bit.ly/3TmGbDi

Scribd : https://bit.ly/3ZmoAwJ

DOI : https://doi.org/10.5281/zenodo.7774058

Abstract : The aim of the work was to determine the best beams number and segments in order to improve the plans conformity and homogeneity that generate low monitor units (MUs) and faster irradiated time for different types of head and neck cancer (HNC).  Methods This study includes 30 patients with different HNC. Intensity modulated radiotherapy (IMRT) treatment planning techniques were done with step and shoot delivery technique, 5, 7 and 9 beams IMRT were carried out for each patient. The treatment plans for all patients were calculated and optimized using fast superposition algorithm. All plans were generated using equal spaced odd beam number around the target. 6 MV were used in all beams. Multiple segments were created for each beam. Typically maximum iteration was carried out to achieve optimized plans. The beam weight optimized to generate the plan, then the segment weight optimized for all plans by using sliding window methods. The final optimization maps were converted into a way of step and shoot sequence map which delivered by linear accelerator using multi leaf collimator (MLC). IMRT plans were compared based on several criteria: Isodose distributions, the mean and standard deviation with pvalues for planning target volume (PTV) 95%, conformity index (CI), homogeneity index (HI), organs at risk (OARs), number of segments, MUs and total irradiated time were presented and compared in all patients. Statically analyses were compared for all patients used ANOVA testes.

Keywords : IMRT, Radiotherapy Techniques, Beam Number, Treatment Planning.