Sadra Medical Journal

Accuracy Assessment of the SWL-LIAC Software Percentage Depth Dose Calculations for Beveled Applicators in the LIAC-12 MeV Intraoperative Radiotherapy Unit

Document Type : Original Article

Authors

Sahar Hashemian 1
Razieh Rashidfar 2
Hossein Parsaei 1
Ahmadreza Azarm 3
Mohammad Amin Mosleh-Shirazi 2, 4

1 Department of Medical Physics and Engineering, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran

2 Ionizing and Non-Ionizing Radiation Protection Research Center, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran

3 Breast Diseases Research Center, Department of Surgery, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran

4 Radiotherapy Physics Unit, Department of Radiooncology, Namazi Hospital, Shiraz University of Medical Sciences, Shiraz, Iran

https://doi.org/10.30476/smsj.2026.104466.1580
Abstract
Introduction: The commissioning and treatment planning of the LIAC 12 MeV intraoperative electron radiotherapy (IOERT) unit rely heavily on the performance of the SWL-LIAC software. This software simulates the relative dosimetric data of the unit based on four percentage depth dose (PDD) curves. This study aimed to evaluate the software’s performance by comparing the simulated and experimentally measured PDD curves.
Methods: Percentage depth dose measurements were conducted for various beveled applicators across all available energies (6, 8, 10, 12 MeV), encompassing 24 fields. Measurements were performed using an E-type electron diode in a water phantom, assisted by custom-made positioning tools, and verified via radiochromic film dosimetry. The measured and calculated PDDs were subsequently compared using one-dimensional gamma analysis.
Results: In the comparisons between the measured PDD curves and the software output for the 24 applicators, the mean gamma passing rate was 100% using a 3 mm/3% (global dose difference) acceptance criterion. When applying a stricter 2 mm/2% criterion, the gamma passing rate for the 3 cm diameter, 15° applicator at 12 MeV was 98.7%, resulting in an overall mean gamma passing rate of 99.9% across all fields at this criterion. The maximum absolute dose difference was 2.9%, which was observed in the 3 cm diameter, 15° applicator at 12 MeV and the 30° applicator at 6 MeV.
Conclusion: The SWL-LIAC software demonstrated sufficient accuracy in its percentage depth dose calculations for beveled applicators.

Keywords

Intraoperative electron radiotherapy
Percentage depth dose
Dosimetry
LIAC accelerator
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Sadra Medical Journal
Volume 14, Issue 2
Spring 2026
Pages 261-269

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