Abstract
The estimation of peripheral dose (PD) is vital in cancer patients with long life expectancy. Assessment of PD to radiosensitive organs is important to determine the possible risk of late effects. An attempt has been made to assess the peripheral dose using optically stimulated luminescence dosimeter (OSLD) with megavoltage photon beams as a function of field size, depth, energy, and distance from the field edge. The PD measurements were carried out at 13 locations starting from 1.5cm to 20.8cm from radiation field edge for three different field sizes at three different depths with 6 and 18 MV photon beams. In addition, the measurements were carried out to analyze the response in PD due to the presence of wedge. The %PD decreases gradually with an increase in distance from the radiation field edge. The %PD at surface for 10 × 10cm2 with 6MV photon beams was 6.77 ± 0.32% and 1.0 ± 0.04% at 1.5cm and 20.8cm away from field edge. For 20 × 20cm2 field, %PD was found to be much higher at surface than at 5cm depth for all distances from field edge. This study demonstrates the suitability of OSLD for PD assessment in megavoltage photon beams. The PD increases as field size increases, primarily due to greater amount of out-of-field scatter generated by larger surface area of the collimator defining the larger field size. An enhancement in PD was observed with wedge when the thick end was oriented towards the OSLDs. This study assessed PD that would be a risk factor of the normal tissue complication and secondary cancer induction.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call