7th Asia-Oceania Congress of Medical Physics and 13th CSMP Annual Meeting NCRP REPORT No.49 STRUCTURAL SHIELDING National Council on DESIGN AND Radiation Protection EVALUATION FOR and Measurements MEDICAL USE OF X RAYS AND GAMMA RAYS OF ENERGIES UP TO 10 Mev www.NCRPonline.org www.ncrp.com NCRP National Council on Radiation Protection and Measurements
7 th Asia-Oceania Congress of Medical Physics and 13th CSMP Annual Meeting National Council on Radiation Protection and Measurements www.NCRPonline.org www.ncrp.com
7th Asia-Oceania Congress of Medical Physics and 13th CSMP Annual Meeting New Issues since NCRP 49 New types of equipment, Some with energies above 10 MV, Many new uses for radiotherapy equipment, Dual energy machines, Room designs without mazes, Varied shielding materials including composites, More published data on empirical methods. Instantaneous Dose Rate interpretation problems
New Issues since NCRP # 49 – New types of equipment, – Some with energies above 10 MV, – Many new uses for radiotherapy equipment, – Dual energy machines, – Room designs without mazes, – Varied shielding materials including composites, – More published data on empirical methods. – Instantaneous Dose Rate interpretation problems 7 th Asia-Oceania Congress of Medical Physics and 13th CSMP Annual Meeting
7th Asia-Oceania Congress of Medical Physics and 13th CSMP Annual Meeting Increased data for: ·neutron production ·capture gamma rays scatter fractions 。scatter albedo 。activation ·laminated barriers ·IMRT factors
Increased data for: • neutron production • capture gamma rays • scatter fractions • scatter albedo • activation • laminated barriers • IMRT factors 7 th Asia-Oceania Congress of Medical Physics and 13th CSMP Annual Meeting
7th Asia-Oceania Congress of Medical Physics and 13th CSMP Annual Meeting Public Dose Limits for continuous exposure Annual limit of 1 mSv ED for man-made sources excluding background and exposures from personal medical care Unless can be documented otherwise, per site limit is 0.25 mSv NCRP116(1993)
Public Dose Limits for continuous exposure NCRP 116 (1993) • Annual limit of 1 mSv ED for man-made sources excluding background and exposures from personal medical care • Unless can be documented otherwise, per site limit is 0.25 mSv 7 th Asia-Oceania Congress of Medical Physics and 13th CSMP Annual Meeting
7th Asia-Oceania Congress of Medical Physics and 13th CSMP Annual Meeting Public Dose Limits 0.25 mSv /yr per site Medical Other (0.53 mSv) sources 15% Annual 1% background Consumer products radiation doses in (0.005- 0.13mS) USA 2% Cosmic, Radon terrestrial, (2.0ms) 3.6 mSv yr intemal 55% (1.0msv) 27%
Public Dose Limits 0.25 mSv / yr per site Annual background radiation doses in USA 3.6 mSv / yr 7 th Asia-Oceania Congress of Medical Physics and 13th CSMP Annual Meeting