suitability of chambers in relative dose measurement of small fields for accelerated photon delivered by a medical linear accelerator

Introduction: using the small field in modern radiotherapy, the present study aimed at measuring the relative dosimetry (scattering factor, percentage depth dose (pdd), and profile of penumbra) with ionization (fc65-g, cc13, cc01) and diode (razor) chambers. material and methods: applying trs-398 in varian clinac™ ix-5982 for 6 mv photon beams, the conditions (pressure, temperature, direction, polarity) were kept the same for a set of field sizes (1 × 1, 2 × 2, 3 × 3, 4 × 4, 5 × 5, 7 × 7, and 10 × 10 cm^2), and relative dosimetry was performed at the north-east cancer hospital, sylhet, bangladesh. results: during the output factor measurement in small fields, the razor showed better results than cc13. taking cc01 as a standard in small fields, the data obtained from the study showed a good agreement with those of the previously published works. conclusion: razor, with extremely small active volume, was very much suited for small field dosimetry, except for pdds.