Appendix learning Flashcards by Maredudd Harris

1 atomic mass unit (AMU) =

half the mass of a carbon 12 atom

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Max electrons to a shell?

2nsquared n= shell number

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Kinetic energy =

half mass velocity squaraed

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Frequency is what relationship to T

= 1 / T

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Velocity in relaton to wavelength and frequency

V = Wavelength x frequency

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intensity in relation to frequency

I = plancks constant x frequency

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intensity in relation to wavelength

I = plancks constant / wavelength

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How do intensity and distance relate to each other

1 / d squared

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in XR - how is heat calculated in J

= wave form x peak kV x mAs

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Temp rise

energy applied / heat capacity

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Compton probability

density / Energy

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Photoelectric prob

density x atomic number cubed / energy cubed

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Factor of reduction

2 to the power of HVl

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LAC and HVL related how

LAC = 0.693 / HVL

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MAC

= LAC / density

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In CR - what is the image place made out of

Barium fluohalidate doped with Euopium ions

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How thick is the image plate in CR

0.3mm

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DQE =

SNR out squared / snr in squared

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In DR what are the scintillators made out of

Indirect -
Caesium iodide with thallium
Matrix is made of amorpheus silicone with Hydrogen

Direct -
amorpheus Selenium

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Indirect scintillator is what and gives off what colour wavelength

Green

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What is the equation of Fill factor

sensitive area / total area

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what is the compression on mammography

usually 100 - 150 N

max 200N

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What are the different focal spot sizes?

Normal radiography is 1mm

mammography

borad 0.3mm
fine 0.1mm

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mammo focus to film distance is always

65cm

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In Fluro - what is the input made out of (both)

aluminium or titanium foil Sodium activitated Caesium iodide (400-500microm thick) BLUE light

what kind of light does the fluro input make

blue

In fluro what is the photocathode?

Anitmony caesium

What is the output screen made of in fluro?

Silver activated cadmium sulphide

How thick is the output in fluro

a few micrometeres only

Gain brightness in fluro =

minification xx flux

in fluro - minification

= (input diameter/output) squared

In Fluro - image intensifier CONVERSION factor =

Luminance of the output / entrance dose rate

Normal minification factor

100

normal flux factor

100

Conversion factor in the region of

10 - 30

Tungstan atomic number and k edge

74 k edge ??

Molybdenum K edge

Rhodium k edge

23.3

SNR

1 / square root of photons

Geometric unsharpness / penumbra equation

Focal spot size x Focus to film distance / focus to object

in radiography - magnification equation

image size/object size = distance to image / distance to detector / distance to object

Sampling frequency in relation to Nyquist limit?

Sampling frequency = 2 x Nyquist frequency

in CT imaging detector array - how many rows and detectors in each row

8 - 64 row with 800 detectors per row

what is pitch?

the movement of the table per rotation / width of acquired slices

How is Hounsefield units worked out?

1000 x (tissue - water / water)

Equation for pixel size in CT

= FOV / image matrix size

CTDI is what

dose to the detector from a single rotation

CTDIw is what

spatial variatio nadjusted dose. 1/3 centre 2/3 periphery

CTDIvol

CTDIw /pitch (accounts for the amount radiated due to pitch)

DLP

CTDI vol x distance scanned

DLP units

mGy / cm

in CT effective dose

DLP x E (e is the value for that region receiving XR)

Aduible sound waves are where>

20 to 20 000 Hz

Speed of sound in tissue

1540m/s

US is what range of F

2 - 18 MEGA H

velocity =

square root of rigidity /desnity

velocity (relation to frequency and wavelength)

f x wavelength

Intensity (dB ratio)

10 log to the power 10 (intensity1 / intesnity 2).

Acoustic impedence =

density x speed of sound in that material

Acoustic impednance units

Kg m-2 s-1

Reflection coefficient

Z2 - Z1 all squared / Z2 plus Z1 all squared

Beam weight in US

focal length x wavelength / diamter of PZT crystal

what is the equation for Resistive Index

peak systolic frequency - end diastolic frequency / peak systolic frequency

Pulsatility index =

peak systolic - minimum frequency / time avaraged max frequency

What is the RI in a normal resistive artery

0.6

Abnormal resistive artery

0.8 - 1.0

Nyquist limit in doppler

PRF / 2

PZT is what thickness

half a wavelenth

matching layer is what thickness

quarter of a wavelength

Near field distance =

Diameter of transducer squared / 4 x wavelenth. or radius squared / wavelenth

PRF =

frame rate x lines per frame

Distance of wave

= time x velocity x 0.5

depth of view

= 0.5 x sound velocity / PRF

What is TI

power emitted / that required to increase temp by 1 degree.

What should TI be?

less than 0.5

What is MI?

peak negative pressure / square root of ultrasound frequency.

What should by MI be less than?

0.7

Time averaged intensity

100 mW cm -2

Total sound energy in US

less than 50 J cm -2

Larmor equation =

precessional frequency = GM ratio x B0

Precessional frequency at 1 Tesla

42MHz

T1 is

time to recover 63% of B0

T2 is

time for transverse to lose 63%