COMMISSIONING OF FIRST STATE OF ART CLINAC DHX MEDICAL LINEAR ACCELERATOR AT SHER- I- KASHMIR INSTITUTE OF MEDICAL SCIENCES, J&K: QUANTITATIVE AND QUALITATIVE DOSIMETRIC ANALYSIS.

Objective: To provide a quantitative and qualitative dosimetric analysis of the results obtained while commissioning the first state of art Clinac DHX Medical Linear Accelerator at Sher- I- Kashmir Institute of Medical Sciences, J&K. Introduction: Radiotherapy is an important modality for cancer treatment management. Treatment of almost all the tumours of various shapes has become possible with modern radiotherapy techniques like 3DCRT, IMRT and IGRT etc. Response of radiation treatment is directly related to the precession in the delivered dose to the patient that in turn depends on the accuracy of the beam data used in the treatment planning process. This data is obtained during the commissioning of the Linear Accelerator (LINAC). The data generated thereof is used for the Treatment Planning System. Recently Sher-i-Kashmir Institute of Medical Sciences (SKIMS) procured its first Medical Linear accelerator (Clinac DHX) from Varian Medical Systems and the same was commissioned successfully. This study is inclined towards the evaluation of the various machine parameters and beam data generated for the said Linear accelerator. Methodology: Various national and international protocols includingTRS-398, AAPM TG-45 and IEC 60976 were followed to obtain the beam data and other machine parameters essential for precise dose delivery to the target volume. Data was generated for both photon and electron beams. Dosimetricequipments including RFA, Ionization Chambers, electrometers and various softwares provided by IBA were used extensively to generate the data. In order to carry out the commissioning of the Eclipse (version 13.6) Planning System, the beam data was generated in accordance to requirement of Anisotropic Analytical Algorithm (AAA) for photon beams and the Electron Monte Carlo (e-MC) for electron beams. Evaluation of the data was made on the basis of parameters like PDD, Dose Profiles, Flatness, Symmetry, Relative output factors, MU Linearity, Beam Quality, Collimator Transmission, Photon leakage, neutron leakage and DLG. Results and conclusion: The results obtained for all the parameters including PDD, Dose Profiles, Flatness, Symmetry, Relative output Factors, MU Linearity, Beam Quality, Collimator Transmission, Photon leakage, neutron leakage and DLG were found to be in compliance with the standards set by various national and international bodies. The machine was therefore deemed to be fit and suitable for use in the cancer patients? treatment.