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Introduction: The study aimed to analyze and determine impact of the 3D-CRT fractionation on risk of secondary cancer. Material and Methods: This study used a patient-specific anthropomorphic phantom, and radiation was performed using the Three Dimensional-Conformal Radiation Therapy Field in Field (3D-CRT FinF) technique with conventional, hypofractionation, and hyperfractionation with a dose of 200 cGy, 260 cGy, and 160 cGy in 25, 16, and 30 fractions respectively. It focused on the contralateral breast, contralateral lung, and ipsilateral lung as Organs at Risk (OAR). In addition, the Dose Volume Histogram (DVH) value, normal tissue complication probability (NTCP), and risk of secondary cancer were evaluated.Results: The results showed that the average dose value (Dmean) for ipsilateral lung with hypofractionation was smaller than conventional and hyperfractionation of 1519.8, 1826.7, and 1753.6 cGy, respectively. Furthermore, hypofractionation also reduced radiobiological effects by 50% in the ipsilateral lung with an NTCP value of 0.01% compared to conventional and hyperfractionation with a value of 0.02%. Hypofractionation reduces the risk of secondary cancer in the contralateral breast, contralateral lung, and ipsilateral lung by 16.38, 17, and 22.31% compared to conventional fractionation and 12.75, 13.54, and 21.34% compared to hyperfractionation, respectively. Conclusion: The dose profiles in OAR was smaller in treatment planning with hypofractionation. EBT3 film verification results showed that the ipsilateral lung received more doses than planned, with an insignificant difference (p>0.05). In radiobiology, the ipsilateral lung has the highest probability of complications in treatment planning with conventional fractionation and hyperfractionation.

Introduction: This study aimed to evaluate the efficacy of a synthesized bolus in the reduction of damage to body tissues and the protection of the organ at risk (OAR) in radiotherapy application. Several properties of the synthesized bolus, including density, transmission factor, and effective mass attenuation coefficient, were investigated. Material and Methods: The materials used comprising of propylene glycol (PG), silicone rubber (SR), and aluminum (Al). The dimension of the synthesized bolus was measured using an acrylic case with a size of 11×11 cm² and thickness sizes of 0.5, 1, and 1.5 cm. Furthermore, the boluses were irradiated by linear accelerator with the photon beam energies of 6 and 10 MV, using linier accelerator (LINAC) Varian 2300ix. Results: In this research,the density of synthesized bolus was evaluated by mass per volume equation. The results showed that the density of bolus was similar to the density of tissue/water, fat, and air. . Furthermore the bolus with the composition of PG 24%, SR 8%, and Al 1.5% of all energies, transmission factors of 0.978 and 0.984, thickness of 1.5 cm, and effective mass attenuation coefficients of 0.0144 and 0.0107 cm²/g had the closest properties to the body tissues in terms of dosimetry characterization. Conclusion: The results revealed that the synthesized bolus could increase the percentage surface dose, reduce skin-sparing effect, and protect OAR. The findings indicated that the synthesized bolus had a potential application in clinical therapy.