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Calc/Const

Const1

Const2

Const3

0

1

Constants and Physical Values

Planck's Constant h, 6.626x10^-34 m²-kg/s

Boltzmann's Constant k, 1.38x10^-23 m²-kg-s^-2K^-1

Electron Mass m_e, 0.511 MeV, 9.11x10^-31 kg

Electron Charge q_e, 1.6x10^-19 C

Proton Mass, 938 MeV, 1.673x10^-27 kg

Neutron Mass, 939 MeV, 1.675x10^-27 kg

Speed of Sound in Tissue, 1540 m/s

Speed of Light c, 3x10⁸ m/s

Standard Man Mass, 70 kg

Molar Gas Constant R, 8.31 J mole^-1 K^-1

Avogadro's Number N_a, 6.02x10²³ atoms/mole

Energy Mass Conversion, 931.48 MeV/amu

Electron Volt, 1.6x10^-19 J/eV

Gyromagnetic Ratio of H, 42.58 MHz T^-1

Gyromagnetic Ratio of P, 17.2 MHz T^-1

Gyromagnetic Ratio of Na, 11.26 MHz T^-1

Ionization Constant W_air/e, 33.97 eV/ion-pair-in-air

Roentgen R, 2.58x10^-4 C/kg

Standard Environmental Conditions

In the US and Canada, Temp: 22 ^oC, Press: 101.33 kPa, Relative humidity between 20%-80%. Applies to air inside ion chamber.

Half Lives of Common Radionuclides

Nucl

T(1/2)

Unit

¹⁸F

110

min

³²P

14.3

da

⁶⁰Co

5.27

yr

⁶⁷Ga

78.3

hr

⁸⁹Sr

50.6

da

⁹⁰Y

2.67

da

⁹⁰Sr

28.8

yr

⁹⁹Mo

2.75

da

^99mTc

6.01

hr

¹⁰³Pd

17.0

da

¹¹¹In

2.80

da

¹²³I

13.2

hr

¹²⁴I

4.18

da

¹²⁵I

59.4

da

¹³¹I

8.03

da

¹³¹Cs

9.69

da

¹³⁷Cs

30.1

yr

¹⁵³Sm

1.93

da

¹⁹⁸Au

2.69

da

¹⁹²Ir

73.8

da

²⁰¹Tl

3.04

da

²²²Rn

3.82

da

²²³Ra

11.4

da

IAEA Dose Rate Constants and TVLs

Nucl

Const

TVL

²⁴Na

0.500

59

⁴²K

0.038

53

⁴³K

0.147

18

⁴⁷Ca

0.150

46

⁵¹Cr

0.005

7

⁵⁹Fe

0.170

44

⁵⁷Co

0.016

0.7

⁵⁸Co

0.150

28

⁶⁴Cu

0.032

25

⁶⁷Ga

0.022

5.3

⁶⁵Zn

0.085

42

⁷⁵Se

0.056

5

^99mTc

0.017

0.9

¹¹¹In

0.084

2.5

¹²⁵I

0.034

0.06

¹²³I

0.044

1.2

¹³¹I

0.057

11

¹⁹²Ir

0.135

12

²⁰¹Tl

0.012

0.6

Dose Rate const (µSv h^-1 MBq^-1@ 1 m). TVL (mm Pb).

Standard Calibration Conditions

Calibrated to deliver 1 cGy/MU at d_max for a 10x10 cm² field at 100 cm source to skin distance (SSD).

PET Dose Rate Constants

Nuclide

Constant

Use

⁶⁸Ga

0.134

EDE

⁸²Rb

0.159

EDE

¹²⁴I

0.185

EDE

¹⁸F

0.143

EDE

Dose Rate const (µSv h^-1 MBq^-1@ 1 m). EDE-Effective Dose Equivalent.

Radiation Weighting Factors

Radiation Type

wF

Photons, Electrons and Muons, all energies

1

Proton

5

Fast Neutrons

10

Alpha particles, fission fragments, heavy nuclei

20

ICRP Tissue Weighting Factors

Tissue

wT

Bone-marrow(red), Colon, Lung, Stomach, Breast, Remainder Tissues*

0.12

Gonads

0.08

Bladder, Esophagus, Liver, Thyroid

0.04

Bone Surface, Brain, Salivary Glands, Skin

0.01

*Remainder Tissues: Adrenals, Extrathoracic (ET) region, Gallbladder, Heart, Kidneys, Lymphatic nodes, Muscle, Oral Mucosa, Pancreas, Prostate, Small Intestine, Spleen Thymus, Uterus/Cervix.

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