Quality assurance of measured photon and electron beams data from a medical linear accelerator

ABSTRACT

The physical and dosimetric properties of the SL-15 linear accelerator [linac] were carried out. The machine produces 6- and 10-MV photons as well as electron energies in the range 4 - 15 Mev. The measurements and calculations included the central axis depth dose, percentage depth dose [PDD], tissue maximum ratio [TMR], surface dose, build-up region, specific energy beam profile specifications and output factor. The data obtained were compared specifications and output factor. The data obtained were compared with the published and calculated data using Radiation Oncology Computer System [ROCS]. The symmetry flatness, uniformity and the beam-profile specifications of SL-15 [linac] were within the manufacture's specifications and acceptable for clinical applications. The D[50], D[80], D[10]/D[20] and D[5]/D[15] are listed for different accelerators as indication for the beam specific energy. The X-ray contamination from SL-15 collimating system was found to be within 4% of the maximum dose. The data obtained allow to be used for inter comparison in radiotherapy centers. National and International, for accurate and uniform dosimetry treatment planning delivery. These records are useful in anticipating or detecting faults in the system and as reference at later date