Document Type : Original Paper
Departement of Physics, Faculty of Mathematics and Natural Science, Universitas Andalas, Padang, West Sumatra, Indonesia
Andalas University Hospital, Padang, West Sumatra, Indonesia
Background: The use of electron radiotherapy is an effective option for treating superficial targets in breast cancer patients, because the electron beam has a rapidly decreasing dose and can deliver minimal doses to surrounding tissues. However, to achieve optimal treatment results it is necessary to use the right bolus material to ensure proper radiation dose distribution. In this study, 3D polylactic acid (PLA) bolus were characterized as human tissue equivalent and specially designed for use in electron radiotherapy of breast cancer.
Materials and Methods: This study uses the main material PLA with variations in the infill percentage when printing, which is (20, 40, 60, 80, and 100) %. Dosimetric characterization included measuring the value of Relative Electron Density (RED) and measuring the absorbed dose using LINAC 15 MeV, which was tested using a breast mannequin and compared with a commercial bolus at Andalas University Hospital.
Results: The results showed that the 3D bolus made of PLA provided uniformity in terms of thickness so that every part of the body surface covered by the bolus would get an even dose. 3D bolus made of PLA in all variations in the infill percentage had a RED value equivalent to human tissue. Materials with a RED value equal to human tissue will interact with radiation similarly to human tissue. They can help ensure that the bolus does not significantly change the radiation dose distribution, achieving optimal treatment outcomes. However, a bolus with an infill percentage of 20% has a RED value closest to the breast RED, which is 0.99 and can absorb radiation of 1.98 Gy more optimally compared to a commercial bolus that can absorb 1.97 Gy from 2 Gy doses given.
Conclusion: The 3D bolus made of PLA can be an effective alternative for treating breast cancer using electron radiotherapy.