Electron-beam therapy: is used to treat superficial tumors at a standard 100 cm source-to-surface distance (SSD). Characteristics of electron beams from an Elekta PreciseTM linear accelerator are presented at a nominal SSD of 100 cm. However, certain clinical situations require the use of an extended SSD. The effects of extended source-to-surface distance (SSD) on the electron beam dose profiles were evaluated for various electron beam energies 6, 8, 10,12 and 15 MeV and the accuracy of various output correction methods was analyzed on an Elekta PreciseTM linear accelerator using a radiation field analyzer (RFA). Effective SSDs was evaluated for field sizes ranging from 6×6, 10×10, 14×14 and 20×20 cm2 for various energies.
Aim of the work
1.Investigate the physical properties of electron beams
at different beam energies.
2.Evaluate the accuracy of dose calculated by
Treatment Planning System (TPS) and measured for
different field configurations.