Studying the characteristics of "small" radiation fields in radiotherapy
With the increasing need of radiation therapy in the treatment of cancer and for better treatment new methods of dose delivery to the tumor began to appear, such as IMRT (intensity modulated radiotherapy), VMAT (volumetric arc therapy), SRS (stereotactic radiosurgery ). All of these techniques allow to deliver dose with "small" radiation fields smaller than 3x3 cm <sup>2</sup>, while homogeneous dose distribution throughout the tumor achieved and organs at risk are most retained. Dosimetry of "small" radiation fields is one of the major problems for medical physicists in treatment planning during radiation therapy that uses linear accelerators. The complicacy in measurement characteristics of "small" radiation fields is in the correct choice of dosimeter. In this article "small" radiation fields are experimentally investigated although defined types of detectors that provide the best precision measurements at different photon energies.