UNITS AND TERMINOLOGY
“Special Units”
SI Units
Exposure
Roentgen
Coulombs / kg
Dose
rad (0.01 Gy)
Gray (100 rad)
Dose Equiv
rem (0.01 Sv)
Sievert (100 rem)
Activity
Curie (2.22 E12 dpm)
Becquerel (1dps)
1 Roentgen
=
2.58 E-4 coulomb / kg in air
=
1 esu / cm in air
3
=
87.7 ergs / gm in air
=
98 ergs / gm in soft tissue
1 rad
=
100 ergs / gm in any absorber
1 Gray
=
10,000 ergs / gm in any absorber
1 rem
=
1 rad x QF
=
0.01 Sv
H
=
DQN (from ICRP 26)
H (Dose Equiv.)
=
D (absorbed dose) x Q (quality factor)
x N (any other modifying factors)
DEFINITIONS
Acute
any dose in a short period of time
Chronic
any dose in a long period of time
Somatic
effects in the exposed individual
Genetic
effects in the offspring of the exposed
individual
Teratogenic
effects in the exposed unborn embryo/fetus
Stochastic
effects for which a probability exists and
increases with increasing dose
Non-Stochastic
effects for which a threshold exists -
(deterministic)
effects do not occur below the threshold
(examples; cataracts, erythema, epilation,
acute radiation syndrome)
1
8
4
UNITS AND TERMINOLOGY
“Special Units”
SI Units
Exposure
Roentgen
Coulombs / kg
Dose
rad (0.01 Gy)
Gray (100 rad)
Dose Equiv
rem (0.01 Sv)
Sievert (100 rem)
Activity
Curie (2.22 E12 dpm)
Becquerel (1dps)
1 Roentgen
=
2.58 E-4 coulomb / kg in air
=
1 esu / cm in air
3
=
87.7 ergs / gm in air
=
98 ergs / gm in soft tissue
1 rad
=
100 ergs / gm in any absorber
1 Gray
=
10,000 ergs / gm in any absorber
1 rem
=
1 rad x QF
=
0.01 Sv
H
=
DQN (from ICRP 26)
H (Dose Equiv.)
=
D (absorbed dose) x Q (quality factor)
x N (any other modifying factors)
DEFINITIONS
Acute
any dose in a short period of time
Chronic
any dose in a long period of time
Somatic
effects in the exposed individual
Genetic
effects in the offspring of the exposed
individual
Teratogenic
effects in the exposed unborn embryo/fetus
Stochastic
effects for which a probability exists and
increases with increasing dose
Non-Stochastic
effects for which a threshold exists -
(deterministic)
effects do not occur below the threshold
(examples; cataracts, erythema, epilation,
acute radiation syndrome)
1
8
4
UNITS AND TERMINOLOGY
“Special Units”
SI Units
Exposure
Roentgen
Coulombs / kg
Dose
rad (0.01 Gy)
Gray (100 rad)
Dose Equiv
rem (0.01 Sv)
Sievert (100 rem)
Activity
Curie (2.22 E12 dpm)
Becquerel (1dps)
1 Roentgen
=
2.58 E-4 coulomb / kg in air
=
1 esu / cm in air
3
=
87.7 ergs / gm in air
=
98 ergs / gm in soft tissue
1 rad
=
100 ergs / gm in any absorber
1 Gray
=
10,000 ergs / gm in any absorber
1 rem
=
1 rad x QF
=
0.01 Sv
H
=
DQN (from ICRP 26)
H (Dose Equiv.)
=
D (absorbed dose) x Q (quality factor)
x N (any other modifying factors)
DEFINITIONS
Acute
any dose in a short period of time
Chronic
any dose in a long period of time
Somatic
effects in the exposed individual
Genetic
effects in the offspring of the exposed
individual
Teratogenic
effects in the exposed unborn embryo/fetus
Stochastic
effects for which a probability exists and
increases with increasing dose
Non-Stochastic
effects for which a threshold exists -
(deterministic)
effects do not occur below the threshold
(examples; cataracts, erythema, epilation,
acute radiation syndrome)
1
8
4
UNITS AND TERMINOLOGY
“Special Units”
SI Units
Exposure
Roentgen
Coulombs / kg
Dose
rad (0.01 Gy)
Gray (100 rad)
Dose Equiv
rem (0.01 Sv)
Sievert (100 rem)
Activity
Curie (2.22 E12 dpm)
Becquerel (1dps)
1 Roentgen
=
2.58 E-4 coulomb / kg in air
=
1 esu / cm in air
3
=
87.7 ergs / gm in air
=
98 ergs / gm in soft tissue
1 rad
=
100 ergs / gm in any absorber
1 Gray
=
10,000 ergs / gm in any absorber
1 rem
=
1 rad x QF
=
0.01 Sv
H
=
DQN (from ICRP 26)
H (Dose Equiv.)
=
D (absorbed dose) x Q (quality factor)
x N (any other modifying factors)
DEFINITIONS
Acute
any dose in a short period of time
Chronic
any dose in a long period of time
Somatic
effects in the exposed individual
Genetic
effects in the offspring of the exposed
individual
Teratogenic
effects in the exposed unborn embryo/fetus
Stochastic
effects for which a probability exists and
increases with increasing dose
Non-Stochastic
effects for which a threshold exists -
(deterministic)
effects do not occur below the threshold
(examples; cataracts, erythema, epilation,
acute radiation syndrome)
1
84