Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
76 Cards in this Set
- Front
- Back
Ct,p
|
273+C/295 x 760/P
|
|
Electrons, formula to find 50% dd
|
E/2.33
|
|
Clinical range Electrons
|
E/3 - E/4
|
|
max energy of scattered photon at 90deg
|
511 keV
|
|
rest energy proton
|
938 MeV
|
|
Daily check, QA, gamma knife
|
timer, safety checks
|
|
List the KiloV units
|
grenz, contact, superficial, ortho
|
|
QA, how often check output for gamma knife?
|
monthly
|
|
Convert amu to MeV
|
1 amu = 931 MeV
|
|
How far do betas travel in tissue?
|
0.5 cm/MeV
|
|
How to calculate change in dose due to pt seperation parallel opposed 6xsw
|
remember 3% per cm
|
|
Conv QA for photons is...
|
2% or 2mm
|
|
Conv QA for electrons is...
|
3%, 3 mm
|
|
Dose under %HVT kidney block
|
10 - 20% depending energy, FS
|
|
HVT superficial units
|
1 - 8 mm Al
|
|
Range energy ortho
|
150 - 500 KvP
|
|
SSD ortho
|
50 - 70 cm
|
|
Dose monitoring system in beam path...
|
dose rate, integral dose, beam symmetry
|
|
tx distance superficial units SSD
|
15 - 20
|
|
What determines beam penumbra?
|
source size, secondary coll
|
|
Conv E MeV to wavelength in meters
|
1.24/lambda
|
|
Activity per unit mass
|
specific activity
|
|
increase eff xray unit
|
Voltage, Z
|
|
Supervoltage therapy, energy
|
500 - 1000 kV
|
|
energy xrays van der Graff
|
2 - 10 MV
|
|
magnifies microwaves in linac
|
klystron
|
|
Describe grazing hit Compton effect
|
photon goes forward, electron at 90 w 0 E
|
|
Describe direct hit Compton
|
Max energy electron, which travels fwd, photon 180
|
|
Max energy Compton photon scattered 180
|
.255 MeV
|
|
Max energy Compton photon scattered 90
|
0.511 MeV
|
|
max Energy compton photon scattered 0
|
energy initial photon
|
|
total KE available for ele positron pair for pair production
|
hf - 1.02 MeV
|
|
Annihilation radiation, energy each annihilation photon
|
0.511 MeV
|
|
Describe the photons created in annihilation radiation
|
Two 0.51 MeV particles scattered in opposite directions
|
|
threshhold kVp for xray tube for Compton effect
|
90 kVp
|
|
define stopping power
|
rate of kinetic energy loss per unit path length
|
|
Number of elements
|
103
|
|
Radioactive thresh hold in Z
|
82
|
|
Name the 3 naturally occuring radioactive series
|
uranium, actinium, thorium
|
|
define: equilibrium isotopes
|
ratio of daughter to parent activity constant
|
|
KE alpha particles
|
5 - 10 MeV
|
|
Describe K capture
|
Electron capture of electron in orbit closest to nucleus, competes with positron decay
|
|
Define fission
|
Bombarding high atomic elements with neutrons
|
|
Describe fusion
|
low mass nuclei combined to produce one nucleus
|
|
formula exposure rate
|
gamma X activity / ISF
|
|
define apparent activity
|
in terms of encapsulated 0.5 mm Pb radium at 1-m
|
|
Gamma factor radium
|
8.25 Rcm^2/mCi-hr WATCH UNITS
|
|
converting mCi to mg-Ra equi
|
strength = gamma/gamma-Ra x app activity mCi
|
|
radial dose important for which low energy sources?
|
I-125, P-103
|
|
Which brachy system implants more dose at periphery?
|
PP
|
|
When do you need more radium in Quimby sys than in PP?
|
When dose rx at min
|
|
Which system uses long lines sources for implants?
|
Paris
|
|
Which implant system calcs rx from basal dose?
|
Paris
|
|
What 3 things needed for implants according ICRU?
|
ref kerma, dim target, ref pts
|
|
Decay I and Pd
|
e capture
|
|
Which nuclides anisotrophy factors?
|
I 125, Pd 103
|
|
Energy radium and radon
|
800 keV
|
|
rad protection stds for nuclear reactors set by this US body
|
NRC
|
|
stds for naturally occuring radionuclides set by this body
|
state
|
|
recomm adhered to by states set by this body
|
NCRP
|
|
Factor that converts dose to bio effect
|
Q
|
|
Negligible risk factor
|
0.01 mSv
|
|
occup dose lens
|
150 mSv
|
|
formula for exposure from brachy sources for rad safety and barrier Thickness
|
X [R] = gamma x activity x time x B / ISF
|
|
Formula to calc # TVLs
|
- log (B)
|
|
Formula to calc thickness of wall from TVL
|
- TVL log (B)
|
|
If B = 10^-5, how many TVLs?
|
5
|
|
5 TVLs of concrete for 6X
|
168 cm
|
|
Year R adopted ICRU as unit
|
1928
|
|
Year Cobalt 60
|
1951
|
|
Si unit X
|
C/kg
|
|
Clinical unit X
|
r
|
|
Energy limit free air ionization measurements
|
3 MeV
|
|
Density of mass in air in thimble chamber increases with...
|
decreasing T and increasing P
|
|
TG report measure'ts absorbed dose
|
51
|
|
In tx breast, dose at chest-lung interface
|
80% or E = depth x 3
|