Radiation shielding and bunker design

Abstract

Recent developments in Radiotherapy treatment technology (Intensity Modulated Radio-therapy (IMRT), Volumetric Arc Radiotherapy, (VMAT) and Flattening Filter Free, (FFF) in addition to new products used to build bunkers place an ever-increasing demand on traditional empirical calculations. They are usually based on look up tables featured in the above publications and employed in spreadsheets to predict the exiting dose rate on the other side of the barrier. Furthermore, upgrades of departments and changing national legislation governing environmental radiation levels reflect in a need to continuously update and validate the spreadsheets. The design of each radiotherapy bunker is unique due to the particular department which requires a reworking of the spreadsheets and calculation. Each review tends to be detailed; time consuming but must be precise (errors are costly when barrier thickness of up to 3.0m concrete is required to attenuate the

Design and Evaluation of Structural Shielding of a Typical Radiotherapy Facility Using EGSnrc Monte Carlo Code

“…Empirical methods of calculation of the thickness of primary and secondary barriers by taking the occupancy and use factors into consideration are well-documented in the National Council on Radiation Protection and Measurements, NCRP report 151, and other documents. [ 4 10 11 ] These reports also present recommendations and technical information related to the design and installation of structural shielding for megavoltage X- and gamma-ray radiotherapy facilities and have been used extensively. Some commercially available software such as MicroShield is also available to ease out complexities involves in the structural shielding calculation.…”

Measurements of Neutron Activation and Dose Rate Induced by High-Energy Medical Linear Accelerator

“…Furthermore, the radiation exposure to workers in the process of dismantling a LINAC which is intended to be disposed after the end of its operation should be considered. According to a disposal company in the Republic of Korea, when the LINAC is transferred for disposal or installed in another institution without dismantling the equipment before its move, the effect of radiation leakage through the crosshair for the beam exit (radiation exposure window) cannot be ignored despite the fact that the LINAC's head is surrounded by lead or iron shields to minimize leakage radiation [9,10].…”