module b computed tomography physics, instrumentation, and imaging
TRANSCRIPT
Module BModule B
Computed Tomography Computed Tomography Physics, Instrumentation, Physics, Instrumentation,
and Imagingand Imaging
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TerminologyTerminology
Algorithm- sequential set of operationsAlgorithm- sequential set of operations
ALARA- As Low As Reasonably ALARA- As Low As Reasonably AchievableAchievable
Aliasing- artifactAliasing- artifact
Alphanumeric (A/N)- letters, numbers, Alphanumeric (A/N)- letters, numbers, symbols found on a key boardsymbols found on a key board
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Analog- coding of dataAnalog- coding of data
Analog-to-digital converter (ADC)- Analog-to-digital converter (ADC)- transforming analog to transforming analog to
digitaldigital
Annotation- clinical or technical Annotation- clinical or technical information added to CT information added to CT
image image
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Applications Program- softwareApplications Program- software
Archive- long term storageArchive- long term storage
Arithmetic Logic Unit (ALU)- Arithmetic Logic Unit (ALU)- computational unit or the CPUcomputational unit or the CPU
Array- detector array- detectors used Array- detector array- detectors used for for rapid samplingrapid sampling
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Array Processor- rapid image Array Processor- rapid image reconstructionreconstruction
Artifact- distortion or error on an Artifact- distortion or error on an imageimage
Attenuation- decrease in intensity of Attenuation- decrease in intensity of x-ray x-ray as it passes through as it passes through mattermatter
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Attenuation Coefficient-Attenuation Coefficient-
Linear Attenuation Coefficient-Linear Attenuation Coefficient-
Mass Attenuation Coefficient-Mass Attenuation Coefficient-
Axial- perpendicular to long axis of a Axial- perpendicular to long axis of a body body partpart
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Back-Projection-Back-Projection-
Simple Back-Projection-Simple Back-Projection-
Summation Method-Summation Method-
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Back–projection Filtered-Back–projection Filtered-
Filtered Back-Projection- Filtered Back-Projection-
Beam Hardening-Beam Hardening-
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Beam Hardening Artifact-Beam Hardening Artifact-
Binary Coded Decimal-Binary Coded Decimal-
BIT- abbreviation for “binary digit”-BIT- abbreviation for “binary digit”-
Blinker Function- keyboard functionBlinker Function- keyboard function
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Blur-Blur-
Blurring-Blurring-
Unsharpness-Unsharpness-
Buffer (Buffer Memory)- peripheral Buffer (Buffer Memory)- peripheral memory memory
unitunit
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BYTE- smallest number of bits BYTE- smallest number of bits manipulatedmanipulated
Calibration- assessing CT accuracyCalibration- assessing CT accuracy
Central Processing Unit (CPU)- Central Processing Unit (CPU)- primary primary computer functionscomputer functions
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Collimator- responsible for beam Collimator- responsible for beam reductionreduction
Computed Radiography- radiograph Computed Radiography- radiograph like like image image
Computer- electronic device capable Computer- electronic device capable of rapid computations of informationof rapid computations of information
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Computer Graphics- process of Computer Graphics- process of annotating and labeling CT imagesannotating and labeling CT images
Control Unit- part of CPUControl Unit- part of CPU
CT numbers- Hounsfield unitsCT numbers- Hounsfield units
Cursor- identifiable markerCursor- identifiable marker
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Data Acquisition System- components Data Acquisition System- components used to produce and collect x-ray dataused to produce and collect x-ray data
Density- relative CT numbersDensity- relative CT numbers
Detector Array- used for rapid samplingDetector Array- used for rapid sampling
Detector Efficiency- ability of the Detector Efficiency- ability of the detector arraydetector array
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Digital- coding of dataDigital- coding of data
Edge Enhancement- a technique Edge Enhancement- a technique
Field of View (FOV)- scan field-of-viewField of View (FOV)- scan field-of-view
Filtered Back-Projection- convolutional Filtered Back-Projection- convolutional methodmethod
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Fluence- total number of photons striking Fluence- total number of photons striking an areaan area
Flux- photons delivered per unit of timeFlux- photons delivered per unit of time
Gantry- movable frameGantry- movable frame
Gantry aperture- central opening in the Gantry aperture- central opening in the gantrygantry
Continue…..Continue…..TerminologyTerminology Gas Detector- commonly used detector Gas Detector- commonly used detector
systemsystem
Generation- term used to classify CT Generation- term used to classify CT machine modelsmachine models
Generator- provides electrical powerGenerator- provides electrical power
Geometric Efficiency- detector Geometric Efficiency- detector characteristiccharacteristic
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High Resolution Contrast- ability to High Resolution Contrast- ability to reproduce tissue with reproduce tissue with
high density high density changeschanges Image Data- processed reconstructed Image Data- processed reconstructed
image dataimage data
Image Quality- degree of image Image Quality- degree of image reproduction reproduction
accuracy accuracy
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Incrementation- movement of CT Incrementation- movement of CT table relative to the gantrytable relative to the gantry
Keyboard-Keyboard- Low Contrast Detect ability- ability Low Contrast Detect ability- ability
of CT of CT system to discriminate system to discriminate between similar between similar densitiesdensities
Matrix- grid of pixelsMatrix- grid of pixels Memory- digital information storageMemory- digital information storage
Continue…..Continue…..TerminologyTerminology Modulation Transfer Function-Modulation Transfer Function-
Monitor-Monitor-
Multi-format Camera- hardcopy deviceMulti-format Camera- hardcopy device
Noise- random fluctuations in the imageNoise- random fluctuations in the image
Partial Volume Effect- condition where a Partial Volume Effect- condition where a voxel voxel is occupied by two is occupied by two different tissuesdifferent tissues
Continue…..Continue…..TerminologyTerminology Period- temporal or spatial durationPeriod- temporal or spatial duration
Peripherals- Peripherals-
Pipeline Reconstruction- technique for scanning Pipeline Reconstruction- technique for scanning and image reconstructionand image reconstruction
Pixel- abbreviation for “picture element cell”Pixel- abbreviation for “picture element cell”
Power Distribution Unit (PDU)- responsible for Power Distribution Unit (PDU)- responsible for channeling incoming voltagechanneling incoming voltage
Continue…..Continue…..TerminologyTerminology Radiotherapy Treatment Planning (RTP)- softwareRadiotherapy Treatment Planning (RTP)- software
RAMTEK- component which handles display RAMTEK- component which handles display capabilitiescapabilities
Region (Range) of Interest (ROI)- technique used Region (Range) of Interest (ROI)- technique used to isolate a given value (Hounsfield number) within to isolate a given value (Hounsfield number) within the imagethe image
Reference Detectors- located at the ends of the Reference Detectors- located at the ends of the detector arraydetector array
Reformat (Reformatted Images)-Reformat (Reformatted Images)-
Continue…..Continue…..TerminologyTerminology Scan- mechanical motionScan- mechanical motion
Scan Data- raw dataScan Data- raw data
Scan Projection Radiography- Scan Projection Radiography-
Scintillation Crystal- crystal detector which Scintillation Crystal- crystal detector which converts x-ray energy into light energyconverts x-ray energy into light energy
Slice- cross-sectional portionSlice- cross-sectional portion
Spatial Frequency- sinusoidal variationSpatial Frequency- sinusoidal variation
Continue…..Continue…..TerminologyTerminology Spatial Resolution- capability of a system Spatial Resolution- capability of a system
to record a distinct image to record a distinct image
Spatial Uniformity- Spatial Uniformity-
Storage Capacity- mega, giga, tera bytesStorage Capacity- mega, giga, tera bytes
Subject Contrast- actual (original) tissue Subject Contrast- actual (original) tissue densities within densities within
the patientthe patient Symbolic Address-Symbolic Address-
Continue…..Continue…..TerminologyTerminology Table (CT)- bed, table or portion of the Table (CT)- bed, table or portion of the
unit on which the patient is placedunit on which the patient is placed
Trace- Trace-
Transformer- component used to transfer Transformer- component used to transfer electrical energy electrical energy
Voxel (Volume Element)- basic volume Voxel (Volume Element)- basic volume unitunit
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Window Level-Window Level-
Window Width-Window Width-
Xenon-Xenon-