BEAM ARRANGEMENT OPTIMIZATION IN A SIMPLE PHANTOM WITH STEREOTACTIC BODY RADIATION THERAPY PROCEDURE

• Main Author: LESTARI (NIM: 20215009), RESTU
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/30344
• Institution: Institut Teknologi Bandung

Radiotherapy is now a widely used as an alternative treatment for a cancer. Medical physicists continue to develop techniques and procedures of radiotherapy that are more convenient and more cost-effective for the patient. Medical physicists develop Stereotactic Body Radiation Therapy (SBRT). SBRT is a radiotherapy procedure that can be used to deliver a high dose of radiotherapy with a few fractions. To deliver high dose, a high accuracy radiotherapy treatment planning is needed. The accuracy of determining the beam arrangement in SBRT is one part of radiotherapy treatment planning that must be considered. This study is focused on the optimization beam arrangement by reviewing the dose distribution from the Monte Carlo simulation by using EGSnrc software for each beam angle and the combination of the beam arrangement, and calculating the optimum value with the cost function. The result of beam arrangement optimization process for each beam angle with energy 6 MV generate a small absorbed dose value in OAR and normal tissue. It shows that normal tissue and OAR optimization with cost function Magome (2017) can achieve the goal that is minimizing absorbed dose in OAR and normal tissue. However, PTV absorbed doses are also obtain a small value. D100 obtains a dose value 40% to 60% of the total dose. As the depth of PTV increase, higher beam energy is required to obtain maximum dose value. When the energy is increased to 10 MV, absorbed doses in PTV are also increased. It is shown in DVH for new PTV drops from a dose value more than 50% to over 70% of the total dose. In SBRT procedure, the simulation should be performed with high energy and optimization of absorbed dose in PTV is needed, so that the PTV volume obtain maximum absorbed dose.