Analysis of Dosimetric Parameters of Linear Accelerator

Abstract

With the advancements in the radiation delivery techniques and modern Linac systems, the need for better quality control devices also arises. Different devices manufactured by companies are available at hospitals and some of these devices are found to be more accurate in one category then others. The main objective of this study to analyze the dosimetric parameters of linear accelerator was to use PTW QUICKCHECK device at radiotherapy department of BINO hospital, Bahawalpur and evaluate their performances in checking the beam uniformity and symmetry in daily QC and other required periodic QC tests. For Daily Quality Control PTW QUICKCHECK device was used daily in the morning checks for 50 days to monitor CAX, beam flatness, GT symmetry, LR symmetry, Beam Quality Factor for electron beam of 6, 9, 12, 15, 18, 22 MeV energies and photon beam of 6, 15 MV energies with 100 MU given to the QUICK CHECK device at dose rate of 300 MU/min. To ensure the stability of data monitored through QUICKCHEC repeatability and reproducibility tests were performed. PTW QUICKCHECK device can be easily setup on daily basis for daily checks. According to the results it is clear that PTW QUICKCHECK device is quite accurate with regard to symmetry measurements as all data is within tolerance range (3%). However, accuracy in flatness measurement shows uncertainties i.e for 6 MV 7.3%, for 15 MV 7.31%, for 6 MeV 16.12%, for 9 MeV 6.92%, for 12 MeV 5.92%, for 15 MeV 4.01%, for 18 MeV 4.01% and for 22 MeV 4.13% of data are within tolerance range.