IJSRSET196325 | Received : 05 May 2019 | Accepted : 28 May 2019 | March-April -2019 [ 6 (3) : 123-131 ] © 2019 IJSRSET | Volume 6 | Issue 3 | Print ISSN: 2395-1990 | Online ISSN : 2394-4099 Themed Section : Engineering and Technology DOI : https://doi.org/10.32628/IJSRSET196325 123 Manufacture and Determination of Absorbent in Bolus Radiotherapy Based On Alginate Using of 8 MeV and 10 MeV Energy Hendra Tampubolon * , Kerista Tarigan, Timbangen Sembiring Department of Physics, University of Sumatera Utara, Medan, Sumatera Utara, Indonesia ABSTRACT Bolus radiotherapy have been created by using material of mixture a silicone rubber as matrix and alginate powder as a filler through chemical solution deposition methods with variation of composition silicone rubber : alginate powder : catalyst (99 : 0 : 1)%wt, (80 : 19: 1)%wt, (80 : 18 : 2)%wt, (80 : 17: 3)%wt, (80 : 16 : 4)%wt and (80 : 15 : 5)%wt. The sample fabrication was done in two steps. The first step of alginate powder is mixed with a solution of rubber and catalyst silicon until homogeneous for 5 minutes with the wet mixing method. The second step of the powder which was homogeneously mixed was printed with glass mould measuring 11 x 11 x 1 cm 3 with variations in thickness of 5 mm, 10 mm and 15 mm then dried at 30 0 . Each bolus sample is already to be characterized which includes: physical properties (density, porosity, and water absorption), mechanical properties (tensile strength, elongation and modulus young) and performance (CT Number and absorbency dose). The characterization results showed that alginate powder: optimum rubber silicon ie (80: 19) wt% at a thickness of 15 mm resulted in a density value of 2.091 x 10 3 kg/m 3 , porosity of 9.82% and water absorption of 1.66%. Mechanical properties with tensile strength 3.37 MPa, elongation at 45.28% and modulus of elasticity of 0.816 MPa. Bolus radiotherapy performance properties relative electron density (RED) values or CT numbers of 1.25 resulted in surface absorbance doses of 8 MeV of 101% and 10 MeV of 108.01%. The results of bolus radiotherapy based on composite alginate powder reinforced by silicone rubber can be applied as a cancer therapy material to replace bolus from wax, and paraffin. Keywords: Alginate, Bolus, Radiotherapy Absorption Dosage, Silicone Rubber I. INTRODUCTION Linear accelerator (Linac) is a radiotherapy device that consists of a number of discrete components that function to accelerate high-energy electrons by using RF waves before electrons reach the target to produce X-rays. Now linear accelerators can produce two differences of energis namely X-rays and electrons [22] . The most widely used electron energy circuit for clinical purposes is 20 MeV. In general, electron beam is used in the treatment of superficial cancer (depth <5cm) [15] . The American Association of Physicists in Medicine TG 25 recommends that the electron beam parameters consist of energy, the size of the radiation field and bolus chosen so that the target volume covers 90% of the prescribed dose. At present, skin cancer treatment is generally done by radiotherapy using a linear accelerator (Linac) using electron beams. In superficial cancer treatment using a linear accelerator component there is a possibility that electrons will hit normal tissue. Therefore a bolus- type material is needed as a radiation shield. Bolus is an equivalent body tissue material placed on the surface of the skin outside the irregular contour of the