2. 2
The International Agency for Research on
Cancer(IARC) recently estimated that 7.6
million deaths worldwide were due to cancer
with 12.7 million new cases per year being
reported worldwide
Breast cancer in females and lung cancer in
males are the most frequently diagnosed cancers
( Freddie Bray et al 2011)
Approximately 50% of all cancer patients will
receive radiation therapyradiation therapy during their course of
illness ( Basker et al 2012 )
3. Basic principles
The purpose of radiation shielding :
To limit radiation exposures to members of the
public and employees to an acceptable level. (
NCRP report no.151 )
Areas
Uncontrolled areas 1 mSv/yr
Controlled areas 5 mSv/yr
NCRP,2007
NCRP,2007
3
4. The purpose of radiation shielding :
To reduce the effective equivalent dose from a linear accelerator to a point
outside the room to a sufficiently low level.
4
In radiation therapy rooms
5. Workload
Use factor
Occupancy factor
Use factor
Walls 1/4
Floor 1/2
Ceiling 1/4 or 1/2
T
Full occupancy
Work areas, offices,
nurses’ stations
1
Partial occupancy
Corridors, restrooms, ..
1/4
Occasional occupancy
Waiting rooms,
stairways, …
1/6
Or
1/16
5
14. 14
It’s toxic
lead is not self supporting needs to be held in place
Relatively transparent to neutrons but decrease energy of neutrons by inelastic scattering
22. 22
Maze vs. direct door
Where the available space
is minimal
Doors are Very heavy
( several tons )
Very expensive
In order to reduce the radiation dose near
the entrance
Is a route for ventilation ducts and electrical
conduits
27. 27
References :
1.Baskar, Rajamanickam, Lee, Kuo Ann, Yeo, Richard, & Yeoh, Kheng-Wei. (2012). Cancer
and radiation therapy: current advances and future directions. International journal of medical
sciences, 9(3), 193.
2.Biggs, Peter J. (2010). Radiation Shielding for Megavoltage Photon Therapy Machines:
Boston: sn.
3.Deye, James A, Rodgers, JE, Wu, RK, Biggs, PJ, McCall, RC, & McGinley, PH. (2005).
Structural Shielding Design and Evaluation from Megavoltage X-and Gamma-Ray Radiotherapy
Facilities. National Cancer Institute, Rockville, Maryland.
4.INTERNATIONAL ATOMIC ENERGY AGENCY, RADIATION PROTECTION IN THE
DESIGN OF RADIOTHERAPY FACILITIES, IAEA, Vienna (2005).
5.Khan, Faiz M, & Khan, FM. (2003). The physics of radiation therapy (Vol. 3): Lippincott
Williams & Wilkins Philadelphia.
6.Turner, James Edward, & Kelsey, Charles A. (1995). Atoms, radiation, and radiation
protection: Wiley New York.
