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Shielding
•
Aim:
to limit radiation exposure to acceptable levels and optimize
protection of staff, patients, visitors and the public
•
It is a
3D
problem
→
wall and ceiling materials and thicknesses - critical
areas close: radiology, nuclear medicine
•
Different considerations are required for: superficial/orthovoltage X Ray
units, simulators, CT, cobalt 60 units, linear accelerators (TBI-IMRT-
SRT), Brachytherapy, Hadrontherapy
•
3 steps procedure: i) establishing a design value for the effective dose in
the occupied area, ii) estimating the radiation field in the area if there were
no shielding, iii) obtaining the
attenuation factor
required to go from ii)
to i)
NCRP 49-151