Page 94 - ARNM-3-2

Advances in Radiotherapy &

Nuclear Medicine

SHORT COMMUNICATION
Influence of variations in photon beam quality

index on tissue inhomogeneity correction
factors in radiation therapy treatment planning

1
Md Akhtaruzzaman * and Pawel Kukolowicz 2
1 Department of Radiation Oncology, Evercare Hospital Chattogram, Chattogram, Bangladesh
2 Department of Medical Physics, Maria Sklodowska-Curie National Research Institute of Oncology,
Warsaw, Poland

Abstract

This study was carried out to investigate how variations in the beam quality
index (QI)-so-called tissue phantom ratio (TPR 20,10 ) affect tissue inhomogeneity
correction factors (ICFs) in external beam radiotherapy treatment plans. A total of
90 three-dimensional conformal radiotherapy (3DCRT) treatment plans for lung,
gynecological, and prostate cancers and 15 stereotactic body radiation therapy
(SBRT) plans for lung cancer were analyzed. For the 3DCRT plans, ICFs were evaluated
across a range of beam QI values. For 6 MV photon beams, the TPR values were
20,10
set at 0.670 ± 3%, while for 15 MV photon beams, the range was 0.760 ± 3%. SBRT
*Corresponding author: plans were generated using two 6 MV photon beam configurations from a Varian
Md Akhtaruzzaman TrueBeam accelerator – one employing a flattening filter (6 MV, TPR = 0.688) and
(akhtaruzzaman@evercarebd.com) 20,10
the other operating in flattening filter-free (FFF) mode (6 MV FFF, TPR 20,10 = 0.632).
Citation: Akhtaruzzaman M, All dose calculations were performed using the Eclipse treatment planning system
Kukolowicz P. Influence of
variations in photon beam quality with the anisotropic analytical algorithm. For the calculations for 3DCRT plans, a 6.0%
index on tissue inhomogeneity variation in the beam QI resulted in maximum differences in ICFs of 16.3% for lung
correction factors in radiation cases with 6 MV beams and 12.5% for 15 MV beams. In gynecological and prostate
therapy treatment planning. Adv
Radiother Nucl Med. cases, the ICF differences remained below 2.0% and 1.0%, respectively. In addition,
2025;3(2):86-91. for lung SBRT plans, a 5.6% discrepancy in TPR between 6 MV and 6 MV FFF
doi: 10.36922/arnm.6851 20,10
beams led to ICF variations of <3.0%. These findings suggest that while variations
Received: December 2, 2024 in the beam QI significantly influence ICFs in lung cancer 3DCRT plans, their impact
Revised: February 20, 2025 is less pronounced in gynecological and prostate treatments. This underscores the
necessity of carefully accounting for beam quality variations during radiotherapy
Accepted: March 14, 2025
treatment planning to ensure accurate dose delivery and optimal patient outcomes.
Published online: March 27, 2025
Copyright: © 2025 Author(s). Keywords: Treatment plans; Photon beams; Inhomogeneity correction factors; Beam quality
This is an Open-Access article
distributed under the terms of the
Creative Commons Attribution
License, permitting distribution,
and reproduction in any medium, 1. Introduction
provided the original work is
properly cited. Radiation therapy has been used for decades to manage a broad spectrum of cancers.7
1,2
Publisher’s Note: AccScience Its efficacy depends on accurately delivering the prescribed dose to the target whereas
Publishing remains neutral with minimizing the dose absorbed by nearby organs at risk. Achieving this objective
regard to jurisdictional claims in
published maps and institutional necessitates precise delineation of all pertinent anatomical structures and meticulous
3
affiliations. dose calculation. According to the International Commission on Radiation Units

Volume 3 Issue 2 (2025) 86 doi: 10.36922/arnm.6851