Suitability of chambers in relative dose measurement of small fields for accelerated photon delivered from medical linear accelerator

Aims: Uses of small field in modern radiotherapy our present work is devoted to measure the relative dosimetry (scattering factors, percentage depth doses and profile’s penumbra) with ionization (FC65-G, CC13, CC01) and diode (Razor) chambers.Methods and materials: Applying TRS-398 in Varian Clinac IX-5982 for 6 MV photon beams keeping the conditions (pressure, temperature, direction, polarity) same for a set of field sizes (1 × 1, 2 × 2, 3 × 3, 4 × 4, 5 × 5, 7 × 7 and 10 × 10 cm2) relative dosimetry was performed at the North East Cancer Hospital, Sylhet, Bangladesh. Results: During output factor measurement in small fields Razor shows better result than CC13. Taking CC01 as a standard one in small field our measured data showed good agreement with previous published works.Conclusion: Razor having extremely small active volume is very suited for small field dosimetry except PDDs was experimentally found.