Envolvement of Quality Control Tests of Treatment Planning System

This Bachelor´s thesis deals with the treatment planning system Short-term Stability Check. They are carried out according to the Recommendations of the SONS using QUASAR phantoms. These phantoms are expensive, difficult to handle and the methodology for these phantoms of yearly Short-term Stability Check is unnecessarily time consuming. Then it is in the interest of the department that the QUASAR phantoms will be replaced by Inhomogeneity Phantom. Also, the National Radiation Protection Institute lends QUASAR phantoms, so they are not always available. The purpose of this thesis is verified if QUASAR phantoms can be replaced by Inhomogeneity Phantom for Short-term Stability Check. The thesis consists of theoretical and practical parts. The theoretical part deals with the treatment planning system, checks of the ionizing radiation sources and technical equipment. The newly developed methodology is derived from Atomic act and the Recommendation of the SONS and as mentioned above. The treatment planning process and its algorithm are described in an independent chapter. The treatment planning is carried out in the system Eclipse. The system includes many functions, which accelerate the creation, selection and verification of treatment plans. In the following chapter are described the individual checks of the ionizing radiation sources, aimed to verify the accuracy of the devices´ parameters. The Quality Assurance of the ionizing radiation is a condition for the treatment quality and radiation protection of patients and personal. Short-term Stability Check is one of these checks. There is also described the technical equipment, which is necessary for the practical part is impossible. It includes TrueBeam linear accelerator, a 2D detector, phantoms and other equipments, such as wedges, filters. In the practical part there are 2 methodologies, the one of research and the second for Short-term Stability Check of the planning system. The research methodology includes sub-chapters that describe the workflow for Short-term Stability Check. This methodology is based upon information from the manuals of technical equipment. Before introducing the proposed methodology into practice it will be necessary to make its independent verification. Thereafter it will be needed to shorten the methodology to send it to the SONS for assessment. The proposed methodology for Short-term Stability Check of the planning system is in agreement with the on Recommendation of the SONS. In the practical part was verified the planned dose in the planning system Eclipse with measured dose only for checks with inhomogeneities. In this study is formulated the hypothesis: "Can be assumed partial or complete replacement phantoms from the firms Modus or AGMECO by Inhomogeneity Phantom supplied by the PTW company". To confirm or refute the hypothesis was collected data of individual doses. Data collection was performed by irradiating the measurement setup: the detector Octavius 729 + Inhomogeneity Phantom + appropriate number of added plates. In total four energies, 6X, 18X, 6XFFF and 10XFFF were used. Data evaluation was provided by gamma analysis, which assesses the location and size of the point in the dose matrix according to previously specified criteria. The criteria were determined by the table Tolerance. These criteria were verified at most of points. The important thing was that the criterion of 10.0 mm; 10.0% required by Recommendation of the SONS was fulfilled by all points, because it concerns a build-up area, penumbra and interfaces with inhomogeneity's. The research was successfull. It confirmed the hypothesis that QUASAR phantoms may be completely replaced by Inhomogeneity Phantom. In case of practical implementation of this methodology, it should facilitate the work and reduce significantly the time needed to perform the checks