CH6: CCD/CMOS Image Capture

CMOS or CCDs: Which uses more power?

CCDs

CMOS or CCDs: which has a greater pixel fill factor?

CCDs

A system that used scintillators that convert x-rays to light, light to electric charge, and store the charge in capacitors is known as a:

CMOS

CMOS or CCDs: which sensor is more susceptible to noise?

CMOS

Which of the 2 technologies, CCDs or CMOS, is more susceptible to noise, has a lower light sensitivity, uses very little power, and is inexpensive to manufacture

CMOS

CMOS or CCDs: which has a lower sensitivity to light? why?

CMOS because the pixels are surrounded with transistors and many of the light photos hit the transistors rather than the photodiode.

What is CMOS stand for?

Complementary metal oxide semiconductor

What are significant contributing factors to noise? (4)

Light photon production, insufficient incident radiation, broken or inoperable pixels, and temperature

This layer in a CCD chip that contains the electron gates is the:

Polysilicon layer

A solid chemical element or compound doped with impurities that make it highly conductive is known as a:

Semiconductor

T/F: Most CMOS detectors us both N-type and P-type transistors to form the electrically controlled gate.

True

Highly efficient and small, a CMOS is a semiconductor that consists what?

a material doped with an impurity such as gallium arsenide or a metal oxide

A charge-coupled device (CCD) acts as what?

a receptor that senses light generated in a scintillator and then sends the light to capacitors in the pixel that converts light to an electrical charge

A charge-coupled device (CCD) does all of the following EXCEPT: a) reduce the size of the projected light image b) transfer the image to a capacitor c) convert light into x-ray photons d) act as receptors biz lenses or fiber optics

d) act as a receptors via lenses or fiber optics

CCD technology has applications in what other modalities?

digital fluoroscopy, stereotactic breast biopsy, digital mammography, and general radiography

What does impurities do to semiconductors of a CMOS?

it makes the semiconductor a full electrical sonductor or the excess electrons become negative or positive transistors.

The number of electron/hole pairs is related to the amount of:

light absorbed

The insulating layer in a CCD chip is the:

silicon dioxide layer

The type and construction of the scintillator, as well as the lenses of fiber optic components, affect what?

spatial resolution and noise

Three types of noise:

statistical, dark current, and amplification

Quantum efficiency of CCD technology is a measure of what?

the efficiency of the light collection and the signal created in the CCD chip

The spectrum sensitivity of a CCD has to match what?

the spectral output of the phosphor in order to gain the greatest efficiency

CMOS systems use scintillators that do what?

when struck with x-ray photons, convert the x-rays into light photons and store them in capacitors