eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-03-31 13 1 221 229 10.13005/bbra/2025 7694 article S. Ahmed 1 M. E. Abdelwanis 1 E. M. Attalla 2 Y. Saddeek 3 E. Shaaban 3 Department of radiotherapy and nuclear medicine south Egypt cancer institute Assiut university Assiut Egypt Department of radiotherapy national institute of cancer Cairo university Cairo Egypt Department of physics Alazhar university Assiut branch Assiut Egypt To compare dosimetric calculation using Clarkson, Convolution, Superposition and Fast Superposition algorithms in Three-Dimensional Conformal Radiotherapy (3D-CRT), and to study the suitability of algorithms with respect to brain tumors and technique. Fifteen brain tumor cases for treatment plans were created using 6 MV Photon beam quality using the CMS XiO (Computerized Medical System, St. Louis, MO) treatment planning system. Patients divided  into two sections according to volume of target more or less than 150cc represented by PTV. Six different  points  were selected to measure the dose. Statistical analysis used: Mean Dose, and Mean Relative Difference have been used Maximum percentage of variation recorded between algorithms was 43.7%, recorded with a surface dose point in case of PTV less than150 cc. The fast superposition algorithm showed excellent results in cases of PTV less than 150ccby considering the mean relative differences with a prescribed dose with four algorithms and minimum relative difference with a prescribed dose in different PTV and treatment techniques. The superposition algorithm showed better results in all techniques. The Clarkson algorithm showed monotonically variation in the dose calculation points and histogram parameters. The other three algorithms are approximately similar in results. Present study has explained  the dosimetric results of different algorithms. https://www.biotech-asia.org/vol13no1/evaluation-of-the-algorithms-accuracy-in-the-computation-of-the-dose-distribution-in-the-brain-tumors/ Algorithm; brain tumors; homogeneity index; treatment planning system