P-479 Evaluation of the Deposed Doses in a Radiotherapy Treatment Room Using the Monte Carlo Geant4 Simulation Platform

Introduction Radiotherapy is considered one of the primary treatment choices in cancer management. The aim of our study is calculating the dose deposited in different points of a radiotherapy treatment room using a phantom detector to quantify the secondary particles around the latter to evaluate the radioprotection level for both the patient and the radiotherapy technician as we increase the distance longitudinally and laterally between the patient and the detector. Methods We used GEANT4 code based on Monte Carlo methods to simulate the radiotherapy treatment room components including the water tank that we centered underneath the beam with a 4.5 MV which is the average energy of the X18 energy spectrum and a fluence of 107 cm−2 to calculate the deposited doses. Results We moved the phantom detector with a step of ±70 cm longitudinally and laterally along X and Z respectively. Findings show that the deposited doses decrease when moving the detector away from the beam’s center for both directions, but it seems higher in the center for X = Z = 0 cm. Discussion The results indicate that even though we increase the distance either longitudinally or laterally between the beam and the detector the diffused dose persists regardless it represents a small amount the fact that validates the principle of distance for protection against external exposure. Conclusion Radiotherapy proved to be highly effective to kill cancer cells, yet the diffused dose persists still inside radiotherapy treatment rooms which creates a debate regarding radioprotection for the patient and the radiotherapy technician.