CCD & CMOS REVIEW EXAM
Who invented CCD technology, and when?
Boyle and Smith in 1969.
What was it initially used for?
Satellites, cameras, and barcodes
Where and when was it initially used in radiography?
1980s in fluoro.
What makes it unique?
All photodiodes are the oldest, have a CCD chip, and p-si pixels.
What are the advantages of CCD?
100% of the pixel is used to detect light, super quick, very compact, individual
broken parts can be readily replaced, very sensitive to light, and more durable than
other digital technologies.
Describe the bucket brigade. What is the only digital detector that uses this
method? Where did the term come from?
Each well passes electrons to the next well; processing is initialised by voltage and
buckets dump it into the next bucket; row by row transfers those electrons to the
reader well; data exits that detector and goes to the computer.
How do I get more electrons into my bucket?
, Increasing mAs
Why do CCD electronics last longer than those in FPD technology?
They do not receive the radiation signal as clearly as the others do.
What's the difference between p-Si and a-Si?
P-si: polysilicon is superior at producing electrons.
A-Si: Amorphous silicon.
What are the advantages of CCD versus FPD?
CCD: quick, bucket brigade occurs within milliseconds, very compact, replacing
the bulky TV tubes (vidicon/plumocon), individual damaged parts may be replaced,
and 100% of pixels are utilised.
What are the advantages of CCD versus CMOS?
CCD: always stays on; more complex.
What factors lead to noise in CCD technology?
Anything that interferes with the signal. Patient size, signal to noise (appropriate
mAs)
What are the three forms of noise seen in CCD technology?
1. Statistical noise (which we can manage).
2. dark current noise (issue is that the CCD is always turned on).
Who invented CCD technology, and when?
Boyle and Smith in 1969.
What was it initially used for?
Satellites, cameras, and barcodes
Where and when was it initially used in radiography?
1980s in fluoro.
What makes it unique?
All photodiodes are the oldest, have a CCD chip, and p-si pixels.
What are the advantages of CCD?
100% of the pixel is used to detect light, super quick, very compact, individual
broken parts can be readily replaced, very sensitive to light, and more durable than
other digital technologies.
Describe the bucket brigade. What is the only digital detector that uses this
method? Where did the term come from?
Each well passes electrons to the next well; processing is initialised by voltage and
buckets dump it into the next bucket; row by row transfers those electrons to the
reader well; data exits that detector and goes to the computer.
How do I get more electrons into my bucket?
, Increasing mAs
Why do CCD electronics last longer than those in FPD technology?
They do not receive the radiation signal as clearly as the others do.
What's the difference between p-Si and a-Si?
P-si: polysilicon is superior at producing electrons.
A-Si: Amorphous silicon.
What are the advantages of CCD versus FPD?
CCD: quick, bucket brigade occurs within milliseconds, very compact, replacing
the bulky TV tubes (vidicon/plumocon), individual damaged parts may be replaced,
and 100% of pixels are utilised.
What are the advantages of CCD versus CMOS?
CCD: always stays on; more complex.
What factors lead to noise in CCD technology?
Anything that interferes with the signal. Patient size, signal to noise (appropriate
mAs)
What are the three forms of noise seen in CCD technology?
1. Statistical noise (which we can manage).
2. dark current noise (issue is that the CCD is always turned on).
