Document Type : Original Research
Authors
- Elnaz Balvasi 1
- Farshid Mahmoudi 2
- Parastoo Farina 1, 3
- Ali Ameri 4, 5
- Fatemeh Jafari 6
- Ghazale Geraily 1, 6
1 Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
2 School of Allied Medical Sciences, Lorestan University of Medical Sciences, Khorramabad, Iran
3 Research Center for Intelligent Technologies in Medicine (RCITM), Advanced Medical Technologies and Equipment Institute (AMTEI), Tehran University of Medical Sciences (TUMS), Tehran, Iran
4 Department of Physics, Stockholm University, Sweden
5 Department of Oncology and Pathology, Karolinska Institutet, Sweden
6 Department of Radiation Oncology, Cancer Institute, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
Abstract
Background: Spatially Fractionated Radiotherapy (SFRT) can be implemented using Volumetric-Modulated Arc Therapy (VMAT) in either two-dimensional (2D) or three-dimensional (3D) configurations.
Objective: This study aimed to compare the dosimetric and clinical outcomes of two VMAT-based SFRT techniques for large lung tumors.
Material and Methods: In this experimental study, SFRT plans were designed for each patient using cylindrical and spherical grid targets. Single-fraction prescription doses of 15 and 20 Gy were delivered to the grid target isocenters using 6 MV Flattening-filter-free (FFF) photon beams.
Results: The 2D SFRT plan demonstrated higher Gross Tumor Volume (GTV) mean dose, GTV Equivalent Uniform Dose (EUD), and Valley-to-peak Dose ratio (VPDR) compared to the 3D lattice plan. However, the 3D Lattice Radiotherapy (3D-LRT) technique provided a better therapeutic ratio and more uniform valley-peak dose distribution. Both plans demonstrated therapeutic ratios greater than one with minimal Normal Tissue Complication Probability (NTCP).
Conclusion: Both 2D and 3D lattice VMAT-based SFRT techniques effectively delivered high radiation doses with steep dose gradients within the GTV, minimizing normal tissue exposure and reducing the risk of complications.
Keywords
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