Dosimetric comparison of photon beam profile characteristics for different treatment parameters. Issue 4 (10th May 2017)

• Record Type: Journal Article
• Authors: Shamsi, Qurat-ul-ain; Atiq, Maria; Atiq, Atia; Ahmad Buzdar, Saeed; Iqbal, Khalid; Iqbal, Muhammad Mazhar
• Is Part Of: Journal of radiotherapy in practice. Volume 16:Issue 4(2016)
• Page Start: 444
• Page End: 450
• Publication Date: 2017-05-10
• Subjects: 6 and 15 MV photon beam profiles, -- homogeneity, -- linear accelerator, -- symmetry; Radiotherapy -- Periodicals; 615.842005
• DOI: 10.1017/S1460396917000292
• Languages: English
• ISSNs: 1460-3969

Abstract

Abstract: Purpose: To deliver radiation doses with higher accuracy, radiation treatment through megavoltage photon beams from linear accelerators, is accepted widely for treating malignancies. Before calibrating the linear accelerators, it is essential to make a complete analysis of all photon beam profile parameters. The main objective of this exploration was to investigate the 6 and 15 MV photon beam profile characteristics to improve the accuracy of radiation treatment plans. Methods: In this exploration, treatment parameters like depth, field size and beam energy were varied to observe their effect on dosimetric characteristics of beam profiles in a water phantom, generated by linear accelerator Varian Clinac. Results: The results revealed that D max and D min decreased with increasing depth but increased with increasing field sizes. Both left and right penumbras increased with increasing depth, field size and energy. Homogeneity increased with field size but decreased with depth. Symmetry had no dependence on depth, energy and field size. Conclusion: All the characteristics of photon beam dosimetry were analysed and the characteristics like homogeneity and symmetry measured by an ion chamber in a water phantom came within clinically acceptable level of 3 and 103%, respectively, thus fulfilled the requirements of standard linear accelerator specifications. This exploration can be extended to the determination of beam profile characteristics of electron and photon beams of other energies at various depths and field sizes for designing optimum treatment plans.