Faculty of Physics - University of Bucharest

UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2025-07-06 15:53

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Conference: Bucharest University Faculty of Physics 2025 Meeting

Section: Biophysics; Medical Physics

Title:

Analysis of external beam treatment planning in Intensity-Modulated Radiation Therapy (IMRT) for head and neck cancers

Authors:

Rebeca Ștefania STROE (1), Bogdan BIȚĂ (1), Mirabela DUMITRACHE (2), Mihaela DUMITRACHE (2)

Affiliation:

1) Faculty of Physics, University of Bucharest

2) Radiotherapy Department, Colțea Clinical Hospital, Bucharest

E-mail

rst042674@gmail.com

Keywords:

Intensity-Modulated Radiation Therapy (IMRT), Head and Neck Cancer, Treatment Planning, Monte Carlo Algorithm, DVH, QA, Gamma Analysis, OAR sparing.

Abstract:

This study evaluates the process and effectiveness of intensity-modulated radiation therapy (IMRT) treatment planning for head and neck cancers (HNC), a complex anatomical region that presents significant challenges in radiation oncology. IMRT, as an advanced radiotherapy technique, enables the delivery of highly conformal dose distributions, optimizing tumor coverage while sparing critical organs at risk (OARs). The research involved retrospective analysis of treatment plans for 10 patients with HNC, designed using the Monaco 6.1.2 treatment planning system, incorporating Monte Carlo dose calculation algorithms. Plans were generated with two different grid spacing values (0.3 cm and 0.4 cm), and comparative dosimetric assessments were performed. Key dose-volume histogram (DVH) parameters and OAR constraints were analyzed to assess plan quality and consistency with clinical goals. To ensure treatment accuracy, pre-treatment verification was carried out using the Octavius 3D phantom and gamma index analysis (3 % dose difference / 3 mm distance to agreement) in Verisoft 7.2 software. Results showed that all plans met gamma analysis acceptance criteria, with passing rates exceeding 95 %. The findings demonstrate that smaller grid spacing values provide slightly improved target coverage and better sparing of normal tissues, without compromising treatment delivery accuracy. The study underscores the critical importance of precise immobilization, CT simulation, and rigorous quality assurance in modern radiotherapy practice. This work contributes to the optimization of IMRT protocols for HNC and emphasizes the role of physics in enhancing clinical outcomes in radiotherapy.

References:

Charles M. Washington, Dennis Leaver (2015) Principles and Practice of Radiation Therapy, 4th ed., Elsevier.

Rehman, J. et al. (2020). Intensity Modulated Radiation Therapy: A Review of Current Practice and Future Outlooks.

Khan, F. M., Gibbons, J. P., Soerduto, P. W. (2016). Treatment Planning in Radiation Oncology, 4th ed., Wolters Kluwer.

Gibbons, J. P. (2024). The Physics of Radiation Therapy, 6th ed., Wolters Kluwer.

Cherry, P., Duxbury, A. (2009). Practical Radiotherapy: Physics and Equipment, 2nd ed., Wiley-Blackwell.

Lee, N. Y., Riaz, N., Lu, J. J. (2015). Target Volume Delineation for Conformal and Intensity-Modulated Radiation Therapy, Springer.

Acknowledgement:

The author expresses sincere gratitude to the Radiotherapy Department at Colțea Clinical Hospital for providing access to clinical data and equipment.