Dosimetric Characteristics of 6 MV Medical Linac at BAEC

Sudeb Kumar Roy,Shirin Akter,Tushar Kumar,Pretam Kumar Das,Md Ashikur Rahman,Rajada Khatun,Mohammad Monjur Ahasan

doi:10.4236/ijmpcero.2021.101004

Abstract

Dosimetric characteristic is one of the essential parameters of a medical linear accelerator (LINAC), which must be obtained before clinical use. The dosimetric characteristics for 6 MV photon beam were measured and compared with the corresponding published data. The study was done using a Varian linear accelerator (Model Clinac-iX) at the Institute of Nuclear Medical Physics (INMP), AERE, Savar, Dhaka, under the Bangladesh Atomic Energy Commission (BAEC). The data is taken for 10 field sizes (2 × 2, 3 × 3, 5 × 5, 7 × 7, 10 × 10, 15 × 15, 20 × 20, 25 × 25, 30 × 30 and 40 × 40 cm2) at same conditions. The measured Percent Depth Dose (PDD) curves were obtained for 6 MV photon beams with the field as mentioned above and compared with the calculated PDD curves. The measured depth dose (Dmax) for reference field size (FS) 10 × 10 cm2 is 15.99 mm, and the PDD at 10 cm depth (D10) is 66.87% for 6 MV photon energies that are found to be compatible with the published report BJR supplement 25. The measured PDD curves for photon energies show a good agreement with the standard PDD curves. The photon beam dosimetry data found in the current study are compatible and all the tolerances are within the clinically acceptable tolerance limit.

Highlights

Dosimetric characteristics are the most important parameter of a linear accelerator (LINAC) which must be obtained prior to clinical use
This is a raw data calculation of 10 different field sizes with a 6 MV photons beam that was performed at the Institute of Nuclear Medical Physics (INMP), Bangladesh Atomic Energy Commission
The process of commissioning an LINAC for clinical use includes comprehensive measurements of dosimetric parameters where a full set of data is acquired that will be used for patient treatment planning

Summary

Introduction

Dosimetric characteristics are the most important parameter of a linear accelerator (LINAC) which must be obtained prior to clinical use. They can produce photon beams, electron beam or both depending on the model used. A linear accelerator can produce high energy x-rays to ensure a tumor’s shape and destroy cancer cells while canning surrounding normal tissue [1]. The linear accelerators have the advantage that the photon beam dosimetric is more penetrating within the cancer cell, a diverse choice of beam energy, a smaller penumbra edge to the beam, and they provide a high dose rate and calculate accurate dose measurement [2]

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