The course provides advanced knowledge of modern methods for the measurement and control of accelerators for radiotherapy. The course covers radiation dosimetry of external beam therapy sources, with special focus on photons and electrons as well as parameters that affect the radiation field appearance and spectral distribution. Also radiation field with protons and light ions are included. Furthermore international protocol for dosimetry and calibration of dosimeters as well as the use of air and liquid ionisation chambers, Fricke, diode, films etc. for the measurement and monitoring of therapy radiation sources are also included. The course also includes dosimetry on brachytherapy sources.