Med Rad 2

Question 1

How to calculate Intensity after passing through a material?

Answer 1

I(x)=(Io)e^-ux

Io=The initial intensity before passing through matter
x=Thickness of material
I=Intensity after going through material
u=How much radiation is weakened as it passes through a material

Question 2

How to calculate Probability of PE

Answer 2

Probability of PE=density (Z^3)/E^3

Question 3

How to calcualte Probability of compton scatter

Answer 3

Probability of compton scatter=Density/Energy

Question 4

How to calculate KE of photoelectron

Answer 4

KE of photoelectron=Incident x-ray photon E (or planck’s constant)-BE of electron

Question 5

How to calculate E of initial photon with PE

Answer 5

E of initial photon with PE=EBE (binding E) +EKE (photoelectron kinetic E)

Question 6

How to calculate E of initial photon with CS

Answer 6

E of initial photon with CS=ES+EBE+EKE

Question 7

How to calculate TMAC

Answer 7

TMAC=u/density

Question 8

How to calculate PEMAC

Answer 8

PEMAC=t/p
CS unit=o (sigma)
PE unit=t
Density unit=p

Question 9

How to calculate CEMAC

Answer 9

CEMAC=o/p

Question 10

How to calculate Probability of PE when using PEMAC

Answer 10

Probability of PE when using PEMAC=t/p (z^3)/E^3)

Question 11

How to calcultae Probability of CS when using CEMAC

Answer 11

Probability of CS when using CEMAC=o/p (p/E)

Question 12

How to calculte u

Answer 12

u= -ln(Ix/Io)/x OR -ln(0.5)/HVL

Question 13

How to calcuate HVL

Answer 13

HVL=I(x)/Io

Question 14

How to calculate TVL

Answer 14

TVL=2.303/u

Question 15

How to calculat PMT gain

Answer 15

PMT gain=g^n
g=dynode gain
n=number of dynodes

Question 16

Flux gain

Answer 16

Flux gain= # of output light photons/ # of input x ray photons

Question 17

Brightness gain

Answer 17

Brightness gain=Flux gain x minification gain

Question 18

Minification gain

Answer 18

Minification gain=d1^2/do^2
the ratio of the input phosphor area to the output phosphor area, resulting in a brighter image due to the concentration of electrons on a smaller surface

d1=Diameter of the IP
do=Diameter of the OP

Question 19

Electronic magnification factor

Answer 19

Electronic magnification factor=IP new size/old IP size

Question 20

Patient dose factor

Answer 20

Patient dose factor=(IP old size/IP new size)^2

Question 21

Read Logarithms:

Answer 21

Logb(X)=Y
b^y=X

Question 22

Acoustic velocity

Answer 22

Acoustic velocity or c=f x λ

Question 23

Intensity

Answer 23

Intensity= 1/distance^2

Question 24

Coulomb’s law:

Answer 24

Coulomb’s law: F=K(q1q2)/d^2
k=9x10^9
q=Charge

Question 25

Effective RMS

Answer 25

Effective RMS=Peak/1.414 The equivalent DC value that would produce the same heating effect in a resistive load, representing the "effective" power delivered by the AC signal

Question 26

Series circuit equations:

Answer 26

Series circuit equations: RT=R1+R2+R3 IT=I1=I2=I3 VT=V1+V2+V3

Question 27

Parallel circuit equations:

Answer 27

Parallel circuit equations: IT=I1+I2 VT=V1=V2 RT=1/r1+1/r2

Question 28

Ratio of induced voltages:

Answer 28

VP/NP=VS/NS n=Number of turns P and S=Primary and secondary

Question 29

Generator rating

Answer 29

Generator rating=KW=mA/10 or kVp X mA/1000

Question 30

Heat U capacity

Answer 30

Heat U capacity=mAs x kVp

Question 31

Magnification factor

Answer 31

Magnification factor=SID/SOD

Question 32

OG Energy of a photon:

Answer 32

OG Energy of a photon: E=hf E=Energy in eV f=frequency in HZ h=PLanks constant (4.15x10^-15 eV*)

Question 33

Speed of light

Answer 33

Speed of light: c=f(λ) c=3x10^8m/s