Linear Accelerator (LINAC) is one of the devices that is often used in external radiation treatment. Photon radiation treatment with targets near the surface results in a poor distribution of doses. Therefore, the use of a substitute tissue-equivalent increases the surface dose of the skin. The study aimed to evaluate the use of the bolus with silicone rubber and silica gel (SRS) to increase the surface dose and determine the percentage difference in a surface dose between measurement and treatment planning systems (TPS). Bolus was fabricated with 11×11 cm2 and a thickness of 0.5 cm and was irradiated by photon energy of 6 MV. The value of a surface dose is measured using an EBT3 film dosimeter using the Three Dimensional Conformal Radiotherapy (3D-CRT) technique. Based on the distribution test of dose on a bolus with a water slab phantom, the surface dose can be increased compared to no bolus with a value of 86.64%. Meanwhile, the percentage difference in surface dose on the thorax phantom between TPS and direct measurements showed a value above 10%. Some suggestions when using film dosimeters require specific designs and markings for placing the film in certain areas to prevent dose verification errors.