Quality Assurance (QA) for medical linear accelerators (linac) is the primary concern in external beam radiation therapy. In this research, we have developed a MATLAB-based software named Quality Assurance for Linacs (QALMA), which is unique, due to cost-effectiveness, user friendly interface, and customizability. It includes five modules to perform different QA tests: Star Shot analysis, Picket Fence test, Winston-Lutz test, MLC log file analysis, and verification of light & radiation field coincidence. We also pay attention to quality assurance of 6DOF treatment couch that plays a very important role in radiation therapy. We developed an Arduino based 3D printed 6DOF robotic phantom to check the accuracy of the treatment couch. This robotic phantom was experimentally validated under clinical standards, and customizable upon requirements of the quality assurance Task. The current features of this robotic phantom open development opportunities beyond the specific couch application, such as organs motion simulation. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection