1. S.A.SH.Kowsarian MD. Imam Khomeini Hospital, Sari

3. Conventional(cgs): curie(Ci) 37 billion decays/sec SI: becquerel(Bq) 1 dacay/sec (rutherford=1000,000 becquerel)

4. Conventional(cgs): Roentgen(R) The amount of ionizing radiation that induce 1 ESU charge in 1 cc of air 1 ESU=1 franklin(Fr)=258 microcoulomb/Kg SI: coulomb(C)

5. Conventional(cgs) : RAD Radiation Absorbed Dose 1 RAD = 100 erg/gr SI : gray(Gy) 1 gray = 1 joule/Kg = 100 RAD

6. Conventional(cgs): REM Radiation Equivalent Man REM=RAD X QUALITY FACTOR (RBE) SI: sievert(Sv) 1 sievert = 100 REM

7. RBE (Relative Biological Effectiveness) Weighting factor Quality factor

8. Radiation typeRBE Electrons, positrons, muons, photons(X- γ ) 1 Neutrons < 10 kev5 Neutrons 10-100 kev10 Neutrons 100 kev-2 mev20 Neutrons > 2 mev5 Alpha ray, fission fragments, heavy nuclei20

9. Dental 0.005 mSv CXR 0.5 mSv Mammo single shot 2 mSv Mammo procedure 4-5 mSv Brain CT 0.8-5 mSv Chest CT 6-18 mSv GI series 14 mSv Average environment yearly 2.4 mSv