Basic Instrumentation + CT Computers

What are the 3 major systems of CT?

imaging, computer, operator (image display, recording, storage + communication)

What are 3 pieces of equipment found in the imaging system?

tube + generator, detectors, collimators

What does the imaging system produce?

x-rays

What does the imaging system convert the attenuation data (collected in detectors) into?

digital information

What are the purposes of the computer system?

receives digital data, processes digital data for image reconstruction, performs image manipulation/post-processing

From where does the computer system receive digital data?

DAS (Data Acquisition System)

What does windowing do?

enhances features of specific anatomy

What does image enhancement do?

smooths and sharpens

What units are used in taking and comparing quantitative measurements?

Hounsfield

What do input and output devices do?

accept and transfer data to PACS (Picture Archiving + Communication Systems)

What do array processors do?

performing high-speed mathematical calculations

What do interface devices do?

help facilitate communication between computers

After how long is information in storage devices typically deleted?

1 week

What is communications hardware?

physical components of machine

What is computer software?

“instructions” that help hardware perform tasks

What are the purposes of the imaging display, recording, storage + communications room?

display output digital image, create hard copy, store + retrieve digital data, communicate images/reports/demographic data to electronic network

What are the 2 main parts of a scanner?

gantry + patient table

What type of generator do current gantries have in CT?

high-voltage

What is the purpose of a high-voltage generator?

provide electricity to x-ray tube + detectors w/ slip rings

What did past models of generators for CT look like?

big + bulky w/ long high-tension cable connecting tube to generator

What type of phase are high-voltage generators in CT?

3

What kVp settings does a high-voltage generator allow?

80 to 140 kVp

What are the common tube currents in CT?

100 to 800 mA

What cools down the large anodes in CT?

oil + air

What do slip rings do?

facilitate electricity

What do scanning control panels do?

tilt gantry + elevate table

What does the scanning control box have?

emergency stop + scan + pause button

What does the multilingual auto-voice intercom system do?

delivers computerized breathing instructions

Why aren’t gantries made any bigger than they are?

limits in rotating capability/weight

What is the typical gantry aperature?

70 cm

What is the Siemens gantry aperature?

78 cm

What is the typical gantry tilting range?

12-30 degrees

What does an EBCT (electron beam CT) tilt instead of its tube?

table

What is another term for patient table?

patient couch

What floats and rests on top of the pedestal in CT?

tabletop

What is the tabletop in CT typically made of?

carbon fiber

What are some benefits in using carbon fiber?

low absorption, excellent vibration dampening, rigid + lightweight

What is the typical weight limit for the tabletop in CT?

400 lbs

What is the weight limit for a Siemen’s tabletop?

676 lbs

What houses the mechanical + electrical components that help move the patient in vertically and horizontally?

pedestal

How much does a CT computer system cost in relation to the overall cost of a CT room?

1/3

What are 4 classifications of computers?

supercomputer, mainframe computer, minicomputer, microcomputer

What type of computer is used in CT workstations?

microcomputer

How many equations can high-speed computers calculate simultaneously?

30,000

What does having multiple processors and storage enable?

high speed data acquisition

What does DICOM stand for?

Digital Information + Communications in medicine

What is the relative humidity computer rooms need to perform?

30%

What does a GPU supply?

additional speed + power to render complicated 3D algorithms

How much faster is a GPU to a CPU?

7.5 times

What type of software corrects data collected from detectors, creating raw data?

preprocessing software

What type of software builds a CT image from raw data?

reconstruction software

What type of data results from reconstruction software?

convolved data

What type of software manipulates reconstructed images?

image processing software

What type of monitors are typically used?

cathode ray tube flat (CRT) display OR liquid crystal display flat panel

How many megabytes does it generally take to store 50 images?

25

What kind of network is required for effective communication?

wide area or local

What does DICOM allow?

image transfer across multivendor + multimodality equipment

What lists how a task should be handled?

protocol

What term describes an approved reference/model?

standard

What are the 2 popular communication protocol standards?

Health Level 7 (RIS/HIS) and DICOM (PACS)

What does the control console in CT allow?

full control of physical system + real-time processing

What are 3 hardware options for CT?

optical disks, optical cartridge tape, independent workstations

What are 3 software options for CT?

3D reconstruction, dynamic scan, bone mineral analysis

What are 3 accessories for CT?

table extenders, additional head holders, immobilization devices

What simplifies scanner upgrades in CT?

modular design concept

What type of operating modes does CT offer?

routine, rapid/dynamic