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;
21 Cards in this Set
- Front
- Back
A set of test to maintain the highest possible quality of equipment is?
|
quality control
|
|
What externally effects equipment performance?
|
temp, wear & tear, humidity, trauma, electrical flux, dirt
|
|
Internal effects that show up on QC tests? 5
|
PMT burnout
Crystal-cracked Defective collimator Electronics Tech problems |
|
QC test order at beginning of day?
|
1st: peak camera
2nd: uniformity then others in any order: resolution(q week), linearity, sensitivty, extrinsic uniformity(q wwk) |
|
What is peaking?
(modern camera does automatically) |
verify centerline is in middle of spectrum
|
|
HOw to perform intrinsic peaking?
|
remove collimator
place 100-200uCi source 5 UFOV's from crystal view gamma spectrum move peak to centerline |
|
What is the purpose of the flood test aka uniformity testing?
|
check for hot or cold spots and adjust camera appropriatly
|
|
3 main types of sources for uniformity testing?
|
1-5mCi Co-57
100-200uCi Tc99m sheet 100-200uCi Tc99m pt source |
|
Procedure intrinsic uniformity
|
1. remove collimator
2. pt source at 5 UFOV, disk on detector (source < 20K c/s) 3. acquire 2million counts 4. film images acquired and check results |
|
CFOV is ?% of UFOV
|
75%
|
|
Max deviation over entire FOV is called?
|
Integral uniformity
|
|
max deviation over a range of FOV (# pixels) called?
|
Differential uniformity
|
|
Ability of camera to reproduce straight lines called?
|
Linearity
|
|
Linearity procedure
|
intrinsic
attach bar phantom pt source Tc @ 5 UFOV distance 2 million counts rotate bar 3x (2min each) analyze images |
|
3 bar phantom types
|
1. 4 quad bar -best resolution
2. Parallel line equal spacing (PLES)- best linearity 3. Hine-Duley- resolution & linearity |
|
4 quad common sizes; how is it read?
|
2mm, 2.5mm, 3mm, 3.5 mm
Read: smallest size bars that you can see=resolution |
|
Hine-Duley how to read this bar phantom?
|
Different sized bars= resolution
straight lines of bars= linearity |
|
Other phantoms? 3
|
Orthagonal: res & linearity
Line: res & linearity Another line: res@ 1 distance & linearity |
|
2 procedures for count rate performance?
|
1. increase rad source w/ lead b/w
2. gradually increase rad source |
|
Why perform count rate test?
|
measures cameras ability to fxn @ count rates near max
|
|
When is a sunurst effect seen?
|
intrinsic count rate perfomance when camera floods and source is too high
|