Design, Development, and Evaluation of Prototype Computed Tomography (CT) Simulator Laser System in Radiotherapy

The main goal of using the computed tomography (CT) simulator is to assimilate the patient's positioning during imaging and treatment. Error in marking can lead to error in patient positioning, and create greater errors in determining the location of the tumor and the treatment planning. The purpose of this study was to design and develop laser system that can greatly reduce these errors.
The laser system consisted of three separate arms that each of them had a fixed laser and a movable laser. In the upper part of each arm, there was a fixed linear laser with a vertical line. In the other part of the arm, there was also a moving linear laser with a horizontal line; this laser moved on the mechanical rail structure inside the arm. Movement and position of the laser was controlled by the electronic system; the electronic system also took order of the Windows-based software.
Findings: In this trial for the performance evaluation, displacement accuracy of the movable lasers was 98.7%, and the displacement precision of them was 0.12 mm.
In this study, using the available facilities, the goal of the study which was design, development, and evaluation the prototype of the CT simulator laser system was achieved. According to the results of this study, the accuracy of the isocentre point determination in this system was 0.5 mm, which is acceptable according to the existing standards, other similar devices, and device usage.