Ct Flashcards
Type of detector
Curvilinear
Type of table
Scissor table
2 stage
1 st stage of table is
Side rails
What is I Link program
It’s when you have a problem with scanner, person can remotely troubleshoot scanner.
The cost of the CT scanner is up to —of the expense.
1/3
Raw data
Has no information in it
Image data
RAS, algorithms, DFOV
Only can change window and level
Array Processor
Adds all the parameters to Raw data to make image data.
Old Scanner is a
Single slice scanner
1 image per revolution
Thickest slice is 10 cm
What was the name of the company that Hounsfield invented CT
EMI
What year did hounds field invent CT in the lab
1967
What year was first full scan unit made
1971
What year was the head scanner in the USA
1973
What year was the full body scanner in the USA
1974
PDU means
Power Distribution Unit
What is the panel on the wall and what does it do
PDU
Distributes power to scanner
Console
SCU
What kind of power is distributed to the console? And where is the console
Low power
Computer is under the desk
SCU
Single Cabinet Unit
What kind of power goes from the PDU to the SCU
Low power
What step up power to energize gantry
HV transformers
What is a balance check
Gantry needs to be balanced every morning, spins very slowly
DAS stands for?
It does?
Digital Acquisition System
Receives energy from crystals and figures out what different densities are. Sends signal to SCU and computer.
What are three types of detectors
- Xenon Crypton Gas
- Scintillation detectors with crystals cesium iodide in the photomultiplier tubes (photodiode)
- Solid-State detectors still use crystals
What are your choices of scan field of view collimation in new scanner
Small is 32 cm
Large is 50 cm
What was the benefit of xenon gas used in detectors
Has a low Z number, so it does not change the wavelength of photon passing through.
The different energy wavelengths will be transmitted to the crystals
What do baffles do?
Absorb long wavelength energy.
What are located in the back of the baffles?
Crystals
What do the crystals do?
Receive information from energy from the x-ray photons that passed through the patient.
The crystal change the energy form, and goes to DAS.
What are DAS boards?
Located on the other side of the detector in old scanners.
The boards send signals to the computer
Problem with old scanner due to centrifugal force
The DAS boards unseat themselves or died.
This caused ring artifact.
Ring artifact has to do with–information
Collecting information
The type of detector in 3rd generation scanner
Solid state detector
Uses crystal
What RAS can’t you change retrospectively
Superior and Inferior
Name of reconstruction after the scan
Retrospective
Name of scan and reconstruction at the time of scan
Prospective
2 pre-patient collimator
SFOV: right and left
Slice thickness: superior and inferior
SFOV collimator opens which way
Right and left
Can you change SFOV after scan
No
Name of screen that you set up lines
View Edit Screen
If you have a case that you may need to see again
Save the raw data
How long is raw data saved? Where? Why?
2 days
Systems disk
Bc it takes so much information on disk
Image data is held for
Up to 2 weeks
Speed of table is determined by
Slice thickness
If taking a 5mm thick picture then the collimator is open how much
5 mm
Post patient collimator
Z-axis of beam
The apperatures open and close with slice thickness
Slick thickness options of new scanner
5 mm
- 5 mm
- 5 mm
- 625 mm
Retrospectively you can change and not change?
Can change space infinity
Can’t change slice thickness
The aperture opening is measured from?
The center and out.
Monthly QA checks?
- Apertures
QA of apertures
If they are opening and closing properly
To make sure the slice thickness is correct
Advantage of new scanner
- Multi-detector saves dose
Detector coverage/scan widest coverage
40 mm
3 options for detector coverage
- Individual slice
- 20 mm scan/ detector coverage
- 40 mm scan / detector coverage
