Radiation Physics Flashcards

1
Q

Energy of packet,

E =

A

E = hv

E energy of packet
h Planck’s constant
v frequency

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2
Q

Speed of light,

c =

A

c = λv

c speed of light
λ wavelength
v frequency

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3
Q

Attenuation per cm in tissue

6MV =

A

6MV: 3.2-3.5%

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4
Q

Attenuation per cm in tissue

10MV =

A

10MV: 2.5%

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5
Q

Attenuation per cm in tissue

15MV =

A

15MV: 2.3%

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6
Q

Attenuation per cm in tissue

Co-60=

A

Co-60: 4.5%

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7
Q

Inhommogeneity due to different tissue density

Lung = _____ x soft tissue density

A

Inhommogeneity due to different tissue density

Lung = 0.3 x soft tissue density

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8
Q

Inhommogeneity due to different tissue density

Bone = _____ x soft tissue density

A

Inhommogeneity due to different tissue density

Bone = 1.6 x soft tissue density

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9
Q

Inhommogeneity due to different tissue density

Air = _____ x less soft tissue density

A

Inhommogeneity due to different tissue density

Air = 800 x less soft tissue density

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10
Q

Wedge angle =

A

Wedge angle =

90 - (hinge angle/2)

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11
Q

Hinge angle =

A

Hinge angle =

180 - (2 x wedge angle)

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12
Q

Exposure
SI unit =
Conventional unit =

A

Exposure
SI unit = C/kg (Coulomb/kg) of air
Conventional unit = R (Roentgen)

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13
Q

Absorbed dose
SI unit =
Conventional unit =

A

Absorbed dose
SI unit = Gy
Conventional unit = rad, J/kg

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14
Q

1 Gy = ____ rad

1 rad= ____ erg/g

A

1 Gy = 100 rad

1 rad= 100 erg/g

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15
Q

Dose equivalent
SI unit =
Conventional unit =

A

Dose equivalent
SI unit = Sv
Conventional unit = rem

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16
Q

Activity
SI unit =
Conventional unit =

A

Activity
SI unit = Bq
Conventional unit = Ci

17
Q

1 Ci =____ Bq

A

1 Ci =3.7 x 10 Bq

18
Q

Prefixes

tera
giga
mega
kilo
milli
micro
nano
pico
A
tera = 10^12
giga = 10^9
mega = 10^6
kilo = 10^3
milli = 10^-3
micro = 10^-6
nano = 10^-9
pico = 10^-12
19
Q

What does D0 dose do for cells?

A

D0 leaves 37% cells still viable

20
Q
Shielding around Linac
Controlled area:
\_\_\_ rem/week
\_\_\_ mSv/week
\_\_\_ mSv/year
\_\_\_ mrem/year
\_\_\_ mR/week
A
Shielding around Linac
Controlled area:
0.1 rem/week
0.1 mSv/week
5 mSv/year
5000 mrem/year
100 mR/week
21
Q
Shielding around Linac
Uncontrolled area:
\_\_\_ mGy/week
\_\_\_ rem/week
\_\_\_ mSv/week
\_\_\_ mSv/year
\_\_\_ mGy/week
A
Shielding around Linac
Uncontrolled area:
0.02 mGy/week
0.02 rem/week
0.02 mSv/week
1 mSv/year
0.02 mGy/week
22
Q
Exposure to developing embryo or fetus after pregnancy is declared
\_\_\_ mSv/mo
\_\_\_ mSv in pregnancy
If no pregnant, 
\_\_\_ mSv/y
A
Exposure to developing embryo or fetus after pregnancy is declared
0.5 mSv/mo
5 mSv in pregnancy
If no pregnant, 
50 mSv/y
23
Q

What is the mechanical isocenter tolerance of gantry rotation?

A

1mm

24
Q

What is the mechanical isocenter tolerance of collide tee rotation?

A

2mm