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