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Dosimetric comparison of photon beam profile characteristics for different treatment parameters

Published online by Cambridge University Press:  10 May 2017

Qurat-ul-ain Shamsi*
Affiliation:
Physics Department, The Islamia University of Bahawalpur, Bahawalpur, Punjab, Pakistan
Maria Atiq
Affiliation:
Physics Department, The Islamia University of Bahawalpur, Bahawalpur, Punjab, Pakistan
Atia Atiq
Affiliation:
Physics Department, The Islamia University of Bahawalpur, Bahawalpur, Punjab, Pakistan
Saeed Ahmad Buzdar
Affiliation:
Physics Department, The Islamia University of Bahawalpur, Bahawalpur, Punjab, Pakistan
Khalid Iqbal
Affiliation:
Shaukat Khanum Memorial Cancer Hospital and Research Center, Lahore, Pakistan
Muhammad Mazhar Iqbal
Affiliation:
Nishtar Medical College Hospital, Multan, Pakistan
*
Correspondence to: Qurat-ul-ain Shamsi, Physics Department, The Islamia University of Bahawalpur, Bahawalpur, Punjab 63100, Pakistan. Tel: 0622875063. E-mail: annieshamsi86@gmail.com

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 Dmax and Dmin 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.

Type
Original Articles
Copyright
© Cambridge University Press 2017 

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