Data
Acquisition
in CT
docsity.com
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Guidelines and tips
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Data Acquisition - Computed Tomography - Lecture Slides, Slides of Computed Tomography
Computed Tomography is an imaging method which uses in X-Rays. This course is part of Radiology courses. This course is basic and important course for Medical students. This lecture includes: Data Acquisition, Data Collection, Acquisition Geometries, Pencil Beam Geometry, Fan Beam Geometry, Comparing Long and Short Geometry, Spiral Geometry, Slip Rings, X-Ray Generator Configurations, Rotating Generator
Typology: Slides
2012/2013
1 / 61
This page cannot be seen from the preview
Don't miss anything!
Related documents
Partial preview of the text
Download Data Acquisition - Computed Tomography - Lecture Slides and more Slides Computed Tomography in PDF only on Docsity!
Data
Acquisition
in CT
Data Collection Basics
X-ray source & detector
must be in & stay in
alignment
Beam moves (scans)
around patient
many transmission measurements
Patient
X-Ray beams
Data Collection Basics (cont)
Beam attenuated by patient
Transmitted photons detected by scanner
Detected photon intensity converted to electrical
signal (analog)
Electrical signal converted to digital value
A to D converter
Digital value sent to reconstruction computer
CT “Ray”
That part of beam falling onto a single detector
Ray
CT View
# of simultaneously collected rays
Scan Requires Many Data Samples
# Data Samples = [# data samples per view] X
[# views]
# Data Samples = [# detectors] X
[# data samples per detector]
Pencil Beam Geometry
Tube-detector assembly translates left to right
Entire assembly rotates 1o
Tube
Detector
1 o
1st Generation CT
Fan Beam Geometry
Tube
Detectors
2nd Generation
3nd Generation
4th Generation
Spiral Geometry
X-ray tube rotates continuously around patient Patient continuously transported through gantry No physical wiring between gantry & x-ray tube Requires “Slip Ring” technology
Tube
Slip Detector Rings
Interconnect Wiring
What’s a Slip Ring?
X-Ray Generator Configurations
with Slip Ring Technology
Problem:
Supply high voltage to a continually rotating x-ray tube?
Options
# Stationary Generator & Transformer # Stationary Generator Transformer & x-ray tube rotate in gantry # Transformer, generator & tube rotate in gantry
Option #1: Stationary High Voltage
Transformer
X-Ray Generator
High Voltage Transformer
X-Ray Tube
Incoming AC Power
Primary Voltage
Secondary Voltage
Option #2: Rotating High Voltage
Transformer
X-Ray Generator
High Voltage Transformer
X-Ray Tube
Incoming AC Power
Primary Voltage
Secondary Voltage
Option #2: Rotating High Voltage
Transformer
low voltage must
pass through slip
rings
Generator Primary Voltage
Tube Slip Detector Rings
HV Transformer
Line Voltage