1. Radiation Measurement12
Radiation Measurement
Units
Röntgen
Rad
Rem
Curie
SI Units
HPT
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2. Röntgen unit of exposure
HPT
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Röntgen
unit of exposure
Does not equate energy deposited to biological damage
No longer addressed by 10CFR20

3. Rad unit of absorbed dose
HPT
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Rad
unit of absorbed dose
Applies to all radiation types in all absorbers
Does NOT account for RBE

4. Relative Biological Effectiveness (RBE)
HPT
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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

5. Linear Energy Transfer (LET)
HPT
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Linear Energy Transfer (LET)
Avg. energy deposited per unit distance traveled
Quality Factor calculated from LET
Relates to biological damage induced by radiation!

6. LET vs. QFs LET (kev/µmeter) Q ≤ 3.5 1 7 2 53 10 ≥175 20 HPT001.007
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LET vs. QFs
LET (kev/µmeter) Q ≤ ≥

7. Röntgen Equivalent Man (Rem)
HPT
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Röntgen Equivalent Man (Rem)
Equates energy deposited to biological damage done
Rem = Rad X Quality Factor
Does account for RBE

8. QFs from 10CFR20 Radiation Type Q X-ray or gamma/Beta particles 1
HPT
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QFs from 10CFR20
Radiation Type Q
X-ray or gamma/Beta particles 1
Thermal Neutrons
Neutrons of unknown energy 10
Alpha particles/FFs 20

9. Curie unit of radioactivity
HPT
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Curie
unit of radioactivity
Amount of material decaying at a rate of 3.7 X 1010 dps
Basis is decay rate of Ra-226

10. SI Units 1 Gray = 100 Rads 1 Sievert = 100 Rem 1 Becquerel = 1 dps
HPT
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SI Units
1 Gray = 100 Rads
1 Sievert = 100 Rem
1 Becquerel = 1 dps