Radiation Physics Flashcards
Energy of packet,
E =
E = hv
E energy of packet
h Planck’s constant
v frequency
Speed of light,
c =
c = λv
c speed of light
λ wavelength
v frequency
Attenuation per cm in tissue
6MV =
6MV: 3.2-3.5%
Attenuation per cm in tissue
10MV =
10MV: 2.5%
Attenuation per cm in tissue
15MV =
15MV: 2.3%
Attenuation per cm in tissue
Co-60=
Co-60: 4.5%
Inhommogeneity due to different tissue density
Lung = _____ x soft tissue density
Inhommogeneity due to different tissue density
Lung = 0.3 x soft tissue density
Inhommogeneity due to different tissue density
Bone = _____ x soft tissue density
Inhommogeneity due to different tissue density
Bone = 1.6 x soft tissue density
Inhommogeneity due to different tissue density
Air = _____ x less soft tissue density
Inhommogeneity due to different tissue density
Air = 800 x less soft tissue density
Wedge angle =
Wedge angle =
90 - (hinge angle/2)
Hinge angle =
Hinge angle =
180 - (2 x wedge angle)
Exposure
SI unit =
Conventional unit =
Exposure
SI unit = C/kg (Coulomb/kg) of air
Conventional unit = R (Roentgen)
Absorbed dose
SI unit =
Conventional unit =
Absorbed dose
SI unit = Gy
Conventional unit = rad, J/kg
1 Gy = ____ rad
1 rad= ____ erg/g
1 Gy = 100 rad
1 rad= 100 erg/g
Dose equivalent
SI unit =
Conventional unit =
Dose equivalent
SI unit = Sv
Conventional unit = rem
Activity
SI unit =
Conventional unit =
Activity
SI unit = Bq
Conventional unit = Ci
1 Ci =____ Bq
1 Ci =3.7 x 10 Bq
Prefixes
tera giga mega kilo milli micro nano pico
tera = 10^12 giga = 10^9 mega = 10^6 kilo = 10^3 milli = 10^-3 micro = 10^-6 nano = 10^-9 pico = 10^-12
What does D0 dose do for cells?
D0 leaves 37% cells still viable
Shielding around Linac Controlled area: \_\_\_ rem/week \_\_\_ mSv/week \_\_\_ mSv/year \_\_\_ mrem/year \_\_\_ mR/week
Shielding around Linac Controlled area: 0.1 rem/week 0.1 mSv/week 5 mSv/year 5000 mrem/year 100 mR/week
Shielding around Linac Uncontrolled area: \_\_\_ mGy/week \_\_\_ rem/week \_\_\_ mSv/week \_\_\_ mSv/year \_\_\_ mGy/week
Shielding around Linac Uncontrolled area: 0.02 mGy/week 0.02 rem/week 0.02 mSv/week 1 mSv/year 0.02 mGy/week
Exposure to developing embryo or fetus after pregnancy is declared \_\_\_ mSv/mo \_\_\_ mSv in pregnancy If no pregnant, \_\_\_ mSv/y
Exposure to developing embryo or fetus after pregnancy is declared 0.5 mSv/mo 5 mSv in pregnancy If no pregnant, 50 mSv/y
What is the mechanical isocenter tolerance of gantry rotation?
1mm
What is the mechanical isocenter tolerance of collide tee rotation?
2mm