Computed Tomography Simulator

Abstract

Abstract A computed tomography simulator (CTsimulator) originally referred to the combination of a radiation therapy dedicated (RT‐dedicated) CT scanner and a simulation workstation that is used for treatment planning in three‐dimensional (3D) conformal radiation therapy. Except for a larger gantry aperture and display field of view (DFOV), as well as a flat top patient couch, an RT‐dedicated CT scanner is virtually identical to a diagnostic CT scanner. The simulation workstation consists of a high quality display screen and a simulation software package. Based on the 3D patient data set acquired by an RT‐dedicated CT scanner, a treatment simulation is conducted to make sure an optimized 3D conformal radiation therapy be delivered to all of the targeted cancerous tumor volume while the inevitable radiation dose absorbed by surrounding normal tissues or organs is as little as possible. Although a CT scanner is currently preferable, other modalities, such as magnetic resonance imaging (MRI), positron emission tomography (PET), or ultrasound, can also be utilized to acquire 3D patient data set for treatment simulation (viz., virtual simulator). In a simulation process, numerous modern 3D visualization techniques, such as 3D volume rendering and surface rendering, are utilized to facilitate anatomic structure identification and radiation beam designing, take care of geometrical uncertainty caused by patient organ motion, such as breathing, swallowing, and assure spatial integrity between an RT‐dedicated CT scanner and a treatment machine. In addition to being employed in conventional 3D conformal radiation therapy, a CT simulator can be utilized in advanced 3D conformal radiation therapy, such as intensity modulated radiation therapy, tomotherapy, or radiosurgery. With the development of advanced 3D conformal radiation therapy techniques, more radiation therapy treatment planning systems are including the functionality of a stand‐alone CT simulator as an integrated component to accomplish an optimized radiation therapy via much more complicated 3D conformal beam‐forming techniques.