Karakteristik berkas foton lapangan kecil setengah lapangan (half beam) dengan menggunakan wedge

This study was aimed to find the profile dose of small field for photon beams on half beam irradiation technique using wedge that can answer the challenge of sino-nasal tumors radiotherapy. The 6 MV photon beam profile measurement is using beam Film Gafchromic EBT3 at depths 1.5 cm, 5 cm and 10 cm for each irradiation field 0.8×0.8 cm2, 1.6×1.6 cm2, 2.4×2.4 cm2, 3.2×3.2 cm2 and 4×4 cm2 using physical wedge angles of 15°, 30°, 45° and 60° and conducted variation of irradiation, thin and thick wedge irradiation. Results shown that FWHM and penumbra values tend to increase along with the depth of measurement. Furthermore, FWHM values tend to be greater than 1.59% when thin wedge irradiation area. Penumbra has a range from 0.15 to 0.36 cm with an anomaly of 80% (n = 135) if defined as the distance 80% - 20% dose points and 0.24% (n = 135) if defined as the distance 50% - 20% dose points. In conclusion, from the measurements, smallest FWHM deviation and penumbra respectively 0.92% and 0.33 cm in the field 0.8×0.8 cm2 wedge 60°, but there is no definite relationship between the wedge with the FWHM value and the penumbra on the small field