Radiation Measurement 12 Radiation Measurement Units Röntgen Rad Rem Curie SI Units HPT001.007 Revision 3 Page of 21

Röntgen unit of exposure HPT001.007 Revision 3 Page of 21 13 Röntgen unit of exposure Does not equate energy deposited to biological damage No longer addressed by 10CFR20

Rad unit of absorbed dose HPT001.007 Revision 3 Page of 21 14 Rad unit of absorbed dose Applies to all radiation types in all absorbers Does NOT account for RBE

Relative Biological Effectiveness (RBE) HPT001.007 Revision 3 Page of 21 15 Relative Biological Effectiveness (RBE) RBE = Dose of 250 kVp X-rays to produce effect Different radiation types are more effective at causing biological damage The Rad does not account for RBE Dose of other radiation for same effect

Linear Energy Transfer (LET) HPT001.007 Revision 3 Page of 21 16 Linear Energy Transfer (LET) Avg. energy deposited per unit distance traveled Quality Factor calculated from LET Relates to biological damage induced by radiation!

LET vs. QFs LET (kev/µmeter) Q ≤ 3.5 1 7 2 53 10 ≥175 20 HPT001.007 Revision 3 Page of 21 17 LET vs. QFs LET (kev/µmeter) Q ≤ 3.5 1 7 2 53 10 ≥175 20

Röntgen Equivalent Man (Rem) HPT001.007 Revision 3 Page of 21 18 Röntgen Equivalent Man (Rem) Equates energy deposited to biological damage done Rem = Rad X Quality Factor Does account for RBE

QFs from 10CFR20 Radiation Type Q X-ray or gamma/Beta particles 1 HPT001.007 Revision 3 Page of 21 19 QFs from 10CFR20 Radiation Type Q X-ray or gamma/Beta particles 1 Thermal Neutrons 2 Neutrons of unknown energy 10 Alpha particles/FFs 20

Curie unit of radioactivity HPT001.007 Revision 3 Page of 21 20 Curie unit of radioactivity Amount of material decaying at a rate of 3.7 X 1010 dps Basis is decay rate of Ra-226

SI Units 1 Gray = 100 Rads 1 Sievert = 100 Rem 1 Becquerel = 1 dps HPT001.007 Revision 3 Page of 21 21 SI Units 1 Gray = 100 Rads 1 Sievert = 100 Rem 1 Becquerel = 1 dps