PT Journal
AU Pujades, MC
   Granero, D
   Vijande, J
   Ballester, F
   Perez-Calatayud, J
   Papagiannis, P
   Siebert, FA
TI Air-kerma evaluation at the maze entrance of HDR brachytherapy facilities
SO Journal of Radiological Protection
JI J. Radiol. Prot.
PY 2014
BP 741
EP 753
VL 34
IS 4
DI 10.1088/0952-4746/34/4/741
LA English
DE bunker; shielding; NCRP 151; brachytherapy; Monte Carlo
AB In the absence of procedures for evaluating the design of brachytherapy (BT) facilities for radiation protection purposes, the methodology used for external beam radiotherapy facilities is often adapted. The purpose of this study is to adapt the NCRP 151 methodology for estimating the air-kerma rate at the door in BT facilities. Such methodology was checked against Monte Carlo (MC) techniques using the code Geant4. Five different facility designs were studied for Ir-192 and Co-60 HDR applications to account for several different bunker layouts. For the estimation of the lead thickness needed at the door, the use of transmission data for the real spectra at the door instead of the ones emitted by Ir-192 and Co-60 will reduce the lead thickness by a factor of five for Ir-192 and ten for Co-60. This will significantly lighten the door and hence simplify construction and operating requirements for all bunkers. The adaptation proposed in this study to estimate the air-kerma rate at the door depends on the complexity of the maze: it provides good results for bunkers with a maze (i.e. similar to those used for linacs for which the NCRP 151 methodology was developed) but fails for less conventional designs. For those facilities, a specific Monte Carlo study is in order for reasons of safety and cost-effectiveness.
ER