1. Module B Computed Tomography Physics, Instrumentation, and Imaging

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3. Terminology Algorithm- sequential set of operations Algorithm- sequential set of operations ALARA- As Low As Reasonably Achievable ALARA- As Low As Reasonably Achievable Aliasing- artifact Aliasing- artifact Alphanumeric (A/N)- letters, numbers, symbols found on a key board Alphanumeric (A/N)- letters, numbers, symbols found on a key board

4. Continue….. Terminology Analog- coding of data Analog- coding of data Analog-to-digital converter (ADC)- transforming analog to digital Analog-to-digital converter (ADC)- transforming analog to digital Annotation- clinical or technical information added to CT image Annotation- clinical or technical information added to CT image

5. Continue….. Terminology Applications Program- software Applications Program- software Archive- long term storage Archive- long term storage Arithmetic Logic Unit (ALU)- computational unit or the CPU Arithmetic Logic Unit (ALU)- computational unit or the CPU Array- detector array- detectors used for rapid sampling Array- detector array- detectors used for rapid sampling

6. Continue….. Terminology Array Processor- rapid image reconstruction Array Processor- rapid image reconstruction Artifact- distortion or error on an image Artifact- distortion or error on an image Attenuation- decrease in intensity of x-ray as it passes through matter Attenuation- decrease in intensity of x-ray as it passes through matter

7. Continue….. Terminology Attenuation Coefficient- Attenuation Coefficient- Linear Attenuation Coefficient- Linear Attenuation Coefficient- Mass Attenuation Coefficient- Mass Attenuation Coefficient- Axial- perpendicular to long axis of a body part Axial- perpendicular to long axis of a body part

8. Continue….. Terminology Back-Projection- Back-Projection- Simple Back-Projection- Simple Back-Projection- Summation Method- Summation Method-

9. Continue….. Terminology Back–projection Filtered- Back–projection Filtered- Filtered Back-Projection- Filtered Back-Projection- Beam Hardening- Beam Hardening-

10. Continue….. Terminology 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 function Blinker Function- keyboard function

11. Continue….. Terminology Blur- Blur- Blurring- Blurring- Unsharpness- Unsharpness- Buffer (Buffer Memory)- peripheral memory unit Buffer (Buffer Memory)- peripheral memory unit

12. Continue….. Terminology BYTE- smallest number of bits manipulated BYTE- smallest number of bits manipulated Calibration- assessing CT accuracy Calibration- assessing CT accuracy Central Processing Unit (CPU)- primary computer functions Central Processing Unit (CPU)- primary computer functions

13. Continue….. Terminology Collimator- responsible for beam reduction Collimator- responsible for beam reduction Computed Radiography- radiograph like image Computed Radiography- radiograph like image Computer- electronic device capable of rapid computations of information Computer- electronic device capable of rapid computations of information

14. Continue….. Terminology Computer Graphics- process of annotating and labeling CT images Computer Graphics- process of annotating and labeling CT images Control Unit- part of CPU Control Unit- part of CPU CT numbers- Hounsfield units CT numbers- Hounsfield units Cursor- identifiable marker Cursor- identifiable marker

15. Continue….. Terminology Data Acquisition System- components used to produce and collect x-ray data Data Acquisition System- components used to produce and collect x-ray data Density- relative CT numbers Density- relative CT numbers Detector Array- used for rapid sampling Detector Array- used for rapid sampling Detector Efficiency- ability of the detector array Detector Efficiency- ability of the detector array

16. Continue….. Terminology Digital- coding of data Digital- coding of data Edge Enhancement- a technique Edge Enhancement- a technique Field of View (FOV)- scan field-of-view Field of View (FOV)- scan field-of-view Filtered Back-Projection- convolutional method Filtered Back-Projection- convolutional method

17. Continue….. Terminology Fluence- total number of photons striking an area Fluence- total number of photons striking an area Flux- photons delivered per unit of time Flux- photons delivered per unit of time Gantry- movable frame Gantry- movable frame Gantry aperture- central opening in the gantry Gantry aperture- central opening in the gantry

18. Continue….. Terminology Gas Detector- commonly used detector system Gas Detector- commonly used detector system Generation- term used to classify CT machine models Generation- term used to classify CT machine models Generator- provides electrical power Generator- provides electrical power Geometric Efficiency- detector characteristic Geometric Efficiency- detector characteristic

19. Continue….. Terminology High Resolution Contrast- ability to reproduce tissue with high density changes High Resolution Contrast- ability to reproduce tissue with high density changes Image Data- processed reconstructed image data Image Data- processed reconstructed image data Image Quality- degree of image reproduction accuracy Image Quality- degree of image reproduction accuracy

20. Continue….. Terminology Incrementation- movement of CT table relative to the gantry Incrementation- movement of CT table relative to the gantry Keyboard- Keyboard- Low Contrast Detect ability- ability of CT system to discriminate between similar densities Low Contrast Detect ability- ability of CT system to discriminate between similar densities Matrix- grid of pixels Matrix- grid of pixels Memory- digital information storage Memory- digital information storage

21. Continue….. Terminology Modulation Transfer Function- Modulation Transfer Function- Monitor- Monitor- Multi-format Camera- hardcopy device Multi-format Camera- hardcopy device Noise- random fluctuations in the image Noise- random fluctuations in the image Partial Volume Effect- condition where a voxel is occupied by two different tissues Partial Volume Effect- condition where a voxel is occupied by two different tissues

22. Continue….. Terminology Period- temporal or spatial duration Period- temporal or spatial duration Peripherals- Peripherals- Pipeline Reconstruction- technique for scanning and image reconstruction Pipeline Reconstruction- technique for scanning and image reconstruction Pixel- abbreviation for “picture element cell” Pixel- abbreviation for “picture element cell” Power Distribution Unit (PDU)- responsible for channeling incoming voltage Power Distribution Unit (PDU)- responsible for channeling incoming voltage

23. Continue….. Terminology Radiotherapy Treatment Planning (RTP)- software Radiotherapy Treatment Planning (RTP)- software RAMTEK- component which handles display capabilities RAMTEK- component which handles display capabilities Region (Range) of Interest (ROI)- technique used to isolate a given value (Hounsfield number) within the image Region (Range) of Interest (ROI)- technique used to isolate a given value (Hounsfield number) within the image Reference Detectors- located at the ends of the detector array Reference Detectors- located at the ends of the detector array Reformat (Reformatted Images)- Reformat (Reformatted Images)-

24. Continue….. Terminology Scan- mechanical motion Scan- mechanical motion Scan Data- raw data Scan Data- raw data Scan Projection Radiography- Scan Projection Radiography- Scintillation Crystal- crystal detector which converts x-ray energy into light energy Scintillation Crystal- crystal detector which converts x-ray energy into light energy Slice- cross-sectional portion Slice- cross-sectional portion Spatial Frequency- sinusoidal variation Spatial Frequency- sinusoidal variation

25. Continue….. Terminology Spatial Resolution- capability of a system to record a distinct image Spatial Resolution- capability of a system to record a distinct image Spatial Uniformity- Spatial Uniformity- Storage Capacity- mega, giga, tera bytes Storage Capacity- mega, giga, tera bytes Subject Contrast- actual (original) tissue densities within the patient Subject Contrast- actual (original) tissue densities within the patient Symbolic Address- Symbolic Address-

26. Continue….. Terminology Table (CT)- bed, table or portion of the unit on which the patient is placed Table (CT)- bed, table or portion of the unit on which the patient is placed Trace- Trace- Transformer- component used to transfer electrical energy Transformer- component used to transfer electrical energy Voxel (Volume Element)- basic volume unit Voxel (Volume Element)- basic volume unit

27. Continue….. Terminology Window Level- Window Level- Window Width- Window Width- Xenon- Xenon-