UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2025-08-20 22:54
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Conference: Bucharest University Faculty of Physics 2025 Meeting


Section: Biophysics; Medical Physics


Title:
Dosimetric differences between coplanar and non-coplanar beam arrangements in Intensity-Modulated Radiation Therapy (IMRT) planning for lung cancer patients


Authors:
Alexandra CIOBANU (1), Constantin PISTOL (1), Mihaela DUMITRACHE (2), Mirabela DUMITRACHE (2)


Affiliation:
(1) Facultatea de Fizică, Universitatea din București

(2) Spitalul Clinic Colțea


E-mail
alexandra.ciobanu666@gmail.com


Keywords:
IMRT, DVH, Radiotherapy, Lung cancer, PTV


Abstract:
The aim of this study is to evaluate and compare the dosimetric impact of coplanar versus non-coplanar beam arrangements in Intensity-Modulated Radiation Therapy (IMRT) planning for patients diagnosed with lung cancer. IMRT is a widely used radiotherapy technique that allows for highly conformal dose distributions, but the geometric configuration of beam angles plays a crucial role in achieving optimal tumor coverage while minimizing exposure to surrounding healthy tissues. This study included 10 patients with lung cancer, planned using an Elekta linear accelerator and the Monaco 6.1.2 treatment planning system. For each patient, two distinct IMRT plans were created: one using coplanar fields, and the other incorporating non-coplanar beam angles. The planning objective was to ensure a minimum of 95 % dose coverage to the Planning Target Volume (PTV) and to reduce radiation exposure to critical Organs at Risk (OARs) such as the lungs, heart, esophagus and spinal cord. Dosimetric parameters were analyzed for both approaches, and in most cases, non-coplanar plans demonstrated superior target coverage and improved sparing of OARs, particularly in complex anatomical situations where beam entry paths could be optimized in three dimensions. All plans underwent patient-specific quality assurance (QA) using VeriSoft 7.2 software, confirming the clinical feasibility of both techniques. The findings suggest that non-coplanar IMRT planning offers potential dosimetric advantages over traditional coplanar approaches, although it implies an increased planning complexity and treatment delivery time.


References:

(1) J. J. L. Nancy Y. Lee, Nadeem Riaz, “Target volume delineation for conformal and intensity-modulated radiation therapy”

(2) S. V. S. Xia, Godley, “Strategies for radiation therapy treatment planning”

(3) A. Taylor and M. Powell, “Intensity-modulated radiotherapy—what is it?” Cancer Imaging, vol. 4

(4) J. R. P. Mayles, A. Nahum, “Handbook of radiotherapy physics. theory and practice”