In each blank, try to type in the
word that is missing. If you've
typed in the correct word, the
blank will turn green.
If your not sure what answer should be entered, press the space bar and the next missing letter will be displayed. When you are all done, you should look back over all your answers and review the ones in red. These ones in red are the ones which you needed help on. Question: What are 2 rights of the ?Answer: 1. Pt has the right to considerate & respectful care. 2. Pt has the to refuse medical treatment. Question: What are the given to the patient before starting any CT exam?Answer: 1. Describe the exam to be performed: area of body, ect. 2. Explain the process of contrast administration. 3. Give any breathing instructions clearly & precisely. Question: Beam Answer: The phenomenon whereby low-energy phontons are absorbed as the x-ray beam passes through an object, resultin in an increase in the photon energy of the beam. Question: Beam Answer: The ratio of table feed per rotation to the total collimation used during acquisition with a multislice CT (MSCT) system. Question: Beam Answer: The dimension of the primary beam in the longitudinal or z-axis as by the pre-patient collimator. Question: Answer: The process of electronically combining signal from adjacent detector elements to a reconstructed CT image that is thicker than the individual width. Question: Bit Answer: The of information bits contained within each pixel. Question: Back-projectionAnswer: The mathematical process of CT image reconstruction whereby ray sum data are projected back onto a . Question: Blood urea (BUN)Answer: A measurement of renal function, as the amount of nitrogen in the blood in the form of the waste product urea.
The normal range is 7-25 mg/dL Question: Bow-tie Answer: A type of filter added to the CT x-ray tube to compensate for the cylindrical shape of most body parts. The filter is thicker at the ends & helps shape the beam to patient radiation exposure. Question: Cardiac Answer: The series of blood flow-related events that from the beginning of one heartbeat to that of the next.
Question: blood flow
(CBF)Answer: A common measurement during CT perfusion studies of the brain. CBF is the quantity of (ML) that moves through 100g of brain tissue each minute.
Normal range in gray matter is 50-60 ML/100g/min Question: Cerebral Answer: The of blood flow throughout brain tissue. Question: Constant Answer: The of milliamperage (mA) and scan time (seconds) utilized for a CT acquisition. Question: Contiguous Answer: CT images acquired with equal thickness and reconstruction intervals. Question: Contrast-induced (CIN)Answer: A substantial decline in renal function that can occur after a patient receives IV material. It is usually signified by a marked increase in serum creatinine over a baseline measurement obtained prior to contrast agent administration. Question: CT BronchographyAnswer: Specialized MSCT examination of the tracheobronchial tree consisting of MPR and rendered 3D images reconstructed from thin, overlapping MDCT axial images through the airways. Question: CT ArthrographyAnswer: CT evaluation of a joint after the intra-articular injection of iodinated contrast . Question: CT EnterographyAnswer: Specialized CT evaluation of the small bowel after the oral administration of low density (0.1%) . Question: CT FluoroscopyAnswer: Continuous real-time CT imaging used predominantly for CT-guided interventional . Question: CT Answer: CT evaluation of the spinal cord and nerve roots after the intrathecal administration of contrast material. Question: CT Answer: Relative value assigned to each pixel to quantify the attenuation occurring in each voxel in comparison with the attenuation of water. The calculated CT number for a given pixel is given in Hounsfield unit (HU). May also be to as pixel value. Question: CT RunoffAnswer: The CT angiographic assessment of the arterial tree from the renal arteries through the lower extremities. Question: CT Answer: The process of obtaining information with CT imaging that is used to calculate the beam arrangement for radiotherapy. Question: CT Answer: Specialized CT evaluation of the large intestine used primarily for colon screening.The large intestine is extended & scanned with thin-section CT. 2D & 3D models are constructed, including virtual endoscopic fly-through views. Question: CT CystographyAnswer: Specialized CT of the bladder whereby iodinated contrast material is administered directly under gravity into the bladder via
Foley catheter. Question: CT Dose (CTDI)Answer: An approximate measure of the dose received in a single CT section or slice. Question: CT Answer: Specialized CT evaluation of the bowel whereby enteral contrast material is administered directly into the duodenum through a nasogastric catheter placed under fluoroscopic guidance. Question: Answer: Mathematical filtration used by the CT system to remove blurring artifact the back-projection method of image reconstruction. Question: Corticomedullary Answer: A late arterial phase of renal enhancement beginning 30-40 seconds after the initiation of contrast agent administration. Optimal enhancement of the renal cortex & renal veins during this period. Question: CreatinineAnswer: A waste product of metabolism found in the bloodstream & measured as an of renal function. Normal range: .5-1.5 mg/dL Question: 180-degree interpolation (180LI)Answer: Type of algorithm used for MSCT reconstruction in which data acquired from a shorter distance (180 degrees) away from the reconstructed slice location are interpolated. Question: 360-degree linear (360LI)Answer: Type of algorithm used for MSCT reconstruction in which two sets of projection data acquired 360 degrees apart are used to form an image at a precise z-axis location. Question: Absorbed Answer: The amount of x-ray absorbed in a unit of mass. It is measured in grays (Gy). Question: Absorption Answer: The ability of an individual CT detector to absorb & measure the transmitted x-ray intensity upon it. Primarily controlled by the characteristics & physical makeup of the detector material. Question: Adaptive Answer: The type of MSCT detector array configured with the detectors at the center, surrounded by detectors of incrementally increasing widths along the a-axis. Question: ImageAnswer: Digital survey radiograph acquired by the CT system for the purpose of prescribing the cross-sectional acquisition. to a conventional radiograph. Question: What mathematical technique is used exclusively for image reconstruction with CT scanners?Answer: Question: ALARAAnswer: The principle that exposure should be kept as low as resonably achievable, economic & social factors being taken into account. Question: AlgorithmAnswer: adapted mathematical calculation applied to raw data during the process of image reconstruction. Computer compatible equation. Question: EffectAnswer: Artifacts that appear on the CT image as fine lines. They occur when too few samples are acquired. Also sampling artifacts. Question: (Al)Answer: Metal most frequently as x-ray beam filter material because it effectively removes low-energy x-rays. Question: (A)Answer: The SI unit of charge. 1A=1 c/s Question: Analog Answer: Continuous display of energy intensity, or radiation, as opposed to the discrete display of a signal. Question: Answer: Positive side of x-ray tube, the target. Question: AnthropomorphicAnswer: Human . Question: resolutionAnswer: The ability of a CT to detect an object with a small difference in linear attenuation coefficient from the surrounding tissue. May also be referred to as low-contrast detectability or sensitivity. Question: AttenuationAnswer: The progressive reduction of the intensity of the x-ray beam, as it through the patient's tissues. Question: Absorbed Answer: Energy transferred from ionizing radiation per unit mass of material. Expressed in rad (100 erg/g) or gray (1J/kg). Question: Answer: Any that absorbs or reduces the intensity of radiation. Question: AbsorptionAnswer: Transfer of energy from radiation to . Removal of x-rays from a beam via the photoelectric effect. Question: AcuteAnswer: Beginning suddenly & running a but rather severe course. Question: effectsAnswer: See early . Question: Added Answer: Aluminum (or its ) of appropriate thickness positioned outside an x-ray tube & in the primary beam. Question: equivalentAnswer: Thickness of a material resulting in the same attenuation as . Question: Answer: American College of Physicists Question: What is the Answer: Professional society of medical . Question: Answer: American Association of in Medicine. Question: What is the Answer: Scientific of medical physicists. Question: American College of (ACR)Answer: Professional of radiologist & medical physicists. Question: American Society of Radiologic (ASRT)Answer: Scientific & society of radiographers. Question: Array Answer: A specialized component of the CT computer system. It is capable of performing the calculations req'd for CT image reconstruction. Question: LipomaAnswer: A benign mass of fat cells. Question: Answer: A common benign mass found in the , consists of muscle cells, blood vessels & fat. Question: What is the average CT value for fat?Answer: -50 to -100 units Question: EfficiencyAnswer: The ability of an individual CT detector to absorb & measure the transmitted x-ray intensity incident upon it. Primarily controlled by the characteristics & makeup of the detector material. Question: Answer: The mathematical technique allowing the reconstruction of motion free from helically acquired CT data. Question: InterpolationAnswer: Is the process whereby data from tube rotations just above & just below a given slice position are used for image reconstruction. Question: The peritoneal cavity is formed by the membranous sac called the ___________.Answer: Question: What does the peritoneal cavity ?Answer: Stomach, liver, gallbladder, , ovaries, transverse colon, & most of the small bowel. Question: CT scan of the should include what?Answer: From the iliac to the pubic symphysis. Question: What is the scan field of view (SFOV) for a CT exam of the CSP?Answer: 50.0 Question: In comparison w/ the surrounding soft tissues, the thyroid gland is ___________.Answer: Hyperdense on the CT. it naturally contains iodine. This density increases further w/ administration of an iodinated contrast agent. Question: The contains some of the most important components of the scanner including what?Answer: 1. CT x-ray tube. 2. Question: What type of information can be entered @ the CT ?Answer: 1. Imaging parameters 2. Post techniques 3. Filming & archiving instructions Question: The scan is responsible for the timing & operation of what?Answer: 1. Patient table 2. Gantry 3. High generator Question: What does DAC for?Answer: Digital-to-Analog Question: What is the easiest way to increase the # of ?Answer: the tube current or the scan time. Question: When should increasing the dose to the be considered?Answer: Only when the result of not doing so would otherwise be a non-diagnostic . Question: Patient Answer: The dose is the amount of ionizing radiation by the patient per unit mass. Question: There is a tradeoff between _______ the image quality & ________ the patient dose.Answer: Minimizing Question: Answer: When a CT image looks grainy or . Question: What made helical imaging ?Answer: rotation scanners. Question: What are 3 of PACS?Answer: 1. Long term data storage 2. Digital distribution of images 3. display for the radiologist Question: Image reconstruction is handled in the _______ ________.Answer: Array Question: -row detector CT scanners:Answer: 1. The size of the detector arrays along the z-direction may be . 2. The attenuation information from adjacent detector arrays may be added together to generate thicker slices. 3. All of the detector arrays may or may not be used. Question: What does mA ?Answer: Quantity of x-ray . Question: State 4 items that are true the collection of CT data.Answer: 1. Short scan times are more desirable. 2. The reconstruction process used to create the image occurs in the array processor. 3. To collect the complete set of CT data, x-rays must be passed through the body at many angles. Question: Answer: 4. The detectors measure x-rays which completely penetrate the . Question: What components are normally in the gantry of a modern CT systems.Answer: 1. x-ray tube 2. 3. collimators (pre-patient & post-patient) Question: Where does the signal go to after it leaves the amplifier component?Answer: The -and-hold component. (S/H) Question: On an ECG of the cardiac cycle, at which portion of the R-R interval is the heart muscle in diastole?Answer: 55% - 75% Question: PhenomenonAnswer: The of gas within a degenerating intervertebral disk. Question: How are spiral/helical CT obtained?Answer: With the scanner continuously acquiring data as the patient travels thru the gantry. The data acquired are volumetric, containing all of the info. for a given area of anatomy. Question: When compared with conventional radiography, CT produces images with improved what?Answer: Low contrast . Question: Complete cardiac diastole correspond to portion of the cardiac cycle on a electrocardiogram (ECG)?Answer: T wave Question: During CT arthrography, contrast media is injected directly into what?Answer: Joint Question: Answer: A benign mass of smooth . It commonly occurs in the uterus & is readily identified on CT exam as a bulky, nonspecific uterine enlargement. Question: The section thickness of a CT scan affects what?Answer: The detail & resolution of the image. Narrow section widths result in greater detail for imaging of small anatomic parts such as the sinuses. Question: What is the thickness for paranasal sinuses?Answer: 3 mm Question: OverbeamingAnswer: Expansion of the primary beam in an MSCT to ensure that all detectors of the array are exposed to x-rays of equal intensity. Question: Name 3 common sites for IV injection of iodinated .Answer: 1. vein 2. Antecubital vein 3. Basilic vein Question: An intrathecal injection prior to a CT exam of the LSP places iodinated contrast material directly into the ________ ______.Answer: space Question: Automatic tube current modulation (ATCM) is employed by an MDCT system for what ?Answer: Reducing radiation dose. Question: High computed tomography (HRCT) is most commonly used for what?Answer: Question: ECG gatingAnswer: Maneuver that may be used to unwanted pulsation artifacts from cardiac motion during a CTA of the chest for pulmonary embolism. Question: Name 4 types of contrast .Answer: 1. Intravascular Radiopaque 2. External Radiopaque 3. Negative contrast 4. Neutral contrast agent Question: The adult spinal cord ends at what level of the lumbar ?Answer: L1-L2 At this it tapers to a point known as the conus medullaris. Question: How are 3D best performed?Answer: With the use of narrow sections acquired with no spacing or an overlap. A detail (bone) algorithm is used for optimal demonstration of bony structures. Question: arrayAnswer: the type of MSCT detector array configured with the thinnest detectors at the center, surrounded by detectors of incrementally widths along the z-axis. Question: Advanced single slice (ASSR) algorithmAnswer: Cone beam algorithm utilized to overcome potential attenuation calculation errors from the divergent beam of MSCT systems. Question: Answer: The tendency of a scintillation type CT detector to continue to glow in response to x-radiation after the source has been terminated. Question: Agatston Answer: Quantification of the volume & density of calcium within the coronary arteries. As calculated during a CT coronary artery calcification (CAG) , the Agatson score is used to indicate a patients risk of suffering a cardiac event. Question: field of view (DFOV)Answer: The diameter of the acquired attenuation data displayed across the image matrix. May also be to as the zoom factor or target view. Question: Scan of view (SFOV)Answer: A parameter that controls the diameter of the circular data acquisition field within the CT gantry as determined by the # of detectors along the x-y axis. May be referred to as calibration field. Question: Answer: Acronym for as low as reasonably achievable, the cardinal principle of radiation dose reduction for all procedures, including CT. Question: AlgorithmAnswer: Mathematical filter applied to raw data during CT image reconstruction to remove blurring artifact inherent to back projection. May also be to as a kernel. Question: AliasingAnswer: A form of streak artifact caused by an insufficient # of (data samples) obtained during data acquisition. Question: Analog-to-digital (ADC)Answer: of the data acquisition system (DAS) responsible for converting the electronic signal emitted by the CT detectors into digital form. Question: Answer: The of CT data in either hard(film) or soft (digital) form. Question: Processor (AP)Answer: Component of the CT computer system responsible for receiving raw scan data, performing all of the major processing of the CT image & returning the image to the storage memory of the host computer. Question: 1st scannersAnswer: - pencil beam - single detector - the tube/detector moved across the patient, then rotated by 1 degree - total scan time about 5 min per image - used for head study - translate-rotate motion Question: 2nd scannersAnswer: - fan beam - multiple detectors in a straight line - the tube/detector assembly moved across the patient, then rotated by 5 degrees - total scan time about 20 secs per image - translate-rotate Question: 3rd scannersAnswer: - fan beam - hundred detectors- curvilinear detector array - 360 degree rotate-rotate motion. Both the x-ray source & the detector array rotate about the same axis. Question: 4th scannersAnswer: *fan beam *multiple detectors encircle the patient and do not rotate around the patient * Only the tube rotates around the patient * Total scan time of 1 per image or faster Question: What are the indications for CT of the head?Answer: Evaluation of , stroke, headache, tumors, endocrine disease, inflammatory disease & congenital problems. Question: The primary goal of CT image reconstruction is to spatially distribute the attenuation data recorded by the _______ _______.Answer: Detector Question: The International Normalized Ratio (INR) is calculated to standardize which value?Answer: time (PT) Question: AsepsisAnswer: Infection control techniques required at the site of IV of iodinated contrast media. Question: What is the goal of multiphasic CT evaluation of a pancreatic mass is what?Answer: The determination of respectively. Question: What are the factors that determine the potential for surgical removal of a pancreatic ?Answer: 1. involvement of the mass 2. local tumor spread 3. metastases Question: Which technology do multirow scanners employ?Answer: 3rd Question: What is scatter caused by?Answer: Deflections from the original trajectory of an x-ray through the patient. Question: The patient table may move _________ during the scan.Answer: Question: Most of the commands from the are received by the what?Answer: Operator's Question: Name 3 things the operator's console may .Answer: 1. monitor 2. 3. graphic input device Question: What does the tube delay time refer to?Answer: The time between the end of one scan and the start of the next scan which the tube will cool. Question: ___ will increase the likelihood that a given x-ray will penetrate a material.Answer: kV Question: Increasing the ____ or exposure time will increase the total number of photons, but will not increase the likelihood that each of those photons will penetrate the material.Answer: Question: How is accomplished?Answer: By blocking x-rays. Question: Scatter radiation is by what?Answer: Deflections from the original trajectory of an x-ray through the patient. Question: Multirow detector scanners employ what type of ?Answer: 3rd Question: In order for an x-ray to be measured it must what?Answer: 1. the detector chamber 2. be absorbed by the detector material 3. be converted to a measurable event. Question: The operator's console may include what 3 ?Answer: 1. monitor 2. keyboard 3. input device Question: Most of the commands from the are received by the:Answer: Operator's Question: The following are true regarding CT :Answer: 1. The gantry can tilt to an angle of approx. 30 degree 2. The patient table, gantry tilt mechanism & rotating gantry assembly all incorporate moving parts. 3. They can a straight coronal or sagittal image. Question: What does the Kv ?Answer: 1. the voltage potential between the tube cathode & anode while mA ultimately controls the filament current & thus the temp. of the cathode filament. 2. the energy level of the x-ray photons & mA controls the # of x-ray emitted from the tube. Question: What are some of the that we directly control that affect spatial resolution?Answer: * slice thickness * display FOV * matrix * the reconstruction filter Question: The full width at half maximum (FWHM) of a CT is used to describe what?Answer: spatial Question: Spatial Answer: The ability of a CT imaging system to display fine details separately. in units of line pairs per centimeter. Question: CT scanner designs use an x-ray tube?Answer: 1st - 4th generation CT PET/CT Question: CT scanner design does not use an x-ray tube?Answer: Electron beam Question: What is the main purpose of the ?Answer: Capture x-ray & convert them to a measurable signal. Question: Transverse slices are always acquired, but studies of the auditory canals, pituitary, orbits, sinuses & facial bones also require what?Answer: Coronal Question: ________ scanner design was the 1st to acquire 4 slices in a single rotation.Answer: -row Detector Question: Tungsten is used as the target material on the tube's anode because it has a ________ atomic # & a _______melting point.Answer: high, Question: What does tube delay time refer to?Answer: The time the end of one scan and the start of the next scan during which the tube will cool. Question: What factors affect the dimensions of a ?Answer: 1. slice thickness 2. matrix size 3. Question: What are the 4 on parameter selection?Answer: 1. contrast 2. spacial resolution 3. image noise 4. patient dose Question: radiation includes which type of electron activity?Answer: 1. collision between an incoming electron & the nucleus of the target atom. 2. slowing down of an incoming electron due to the effect of passing close to the charge of the nucleus of the target atom. Question: Why are x-rays produced whenever fast electrons collide with any form of matter?Answer: The electron loses energy which is converted into the emission of an x-ray photon. Question: Ray Answer: The of transmitted radiation made by an individual detector. Question: The information included during the 3D reconstruction of a CT scan is controlled by the _________ __________.Answer: setting Question: DiastoleAnswer: Refers to the of heart muscle. Question: High-osmolar media (HOCM)Answer: Are ionic agents that dissociate into charged particles (ions) in . Question: Ionic contrast Answer: Are salts consisting of and/or meglumine. Question: OrthogonalAnswer: Imaging planes that are to each other. Question: Segmenting the data acquisition process into seperate components of smaller rotation angles may improve _______ ________.Answer: Temporal Question: _______ _______ artifacts are unique to MSCT systems.Answer: Cone Question: What are 2 analytic methods of CT image ?Answer: 1. back-projection 2. fourier transform method Question: Why are the called analytic?Answer: Because they utilize precise formulas for reconstruction. Question: The photon energy of the CT x-ray beam can be increased by increasing what?Answer: Filtration Question: Answer: Solid state device used to record the light flashes off by a scintillation crystal. Question: tube current modulation (ATCM)Answer: Software used in current MDCT systems to patient radiation dose. Question: Uniform matrix Answer: The type of MSCT detector array that utilizes multiple detectors in the longitudinal , each of the same length. Question: High resolution Answer: Is a specialized technique using narrow section & a high resolution algorithm for image reconstruction. It is used to maximize detail of high spatial frequency tissue, such as the lungs & bony structures. Question: Simple cysts of the have average attenuation values in the range of what?Answer: 0 to +20 units Question: The abdominal aorta bifurcates at the level of _______.Answer: Question: Contrast enhancement of vasulature greatly aids in the diagnosis of many including....Answer: 1. aneurysm 2. 3. stenosis Question: What is dose?Answer: The quantity of absorbed radiation dose based on the radiosensitivity of a tissue type. Question: What is the normal rate for blood pressure in adults?Answer: 60-90 mm Question: What is diastolic ?Answer: The measurement of blood pressure at its lowest point, in between of the heart. Question: What is cardiac diastole?Answer: The of atrial & venticular relaxation after heart contraction. Question: What wave of an ECG to cardiac diastole?Answer: T wave Question: Name general signs & symptoms that a is going into shock.Answer: 1. rapid breathing 2. tachycardia 3. hypotension 4. weak 5. pallor 6. cyanosis 7. cold clammy skin Question: __________ is a parenteral route of meication administration.Answer: Question: Name 3 methods that may be employed to radiation dose to pediatric CT patient's.Answer: 1. reduce mA 2. limit of acquisition 3. increase pitch Question: Radiation exposure & its potentially harmful effects have a relationship that is termed __________.Answer: Question: What type of technique protects against infection transmitted through fecal material?Answer: precautions Question: Mild reactions to contrast media include:Answer: 1. nausea/vomitting 2. mild urticaria (hives) 3. pronounced sensation of warmth and/or flushing 4. altered taste 5. sweat/chills 5. stuffiness/sneezing 6. anxiety Question: Moderate reactions to iodinated contrast agents :Answer: 1. mild bronchospasm 2. moderate to severe urticaria (hives) 3. response 4. tachycardia from hypotension Question: Severe reactions to iodinated contrast :Answer: 1. profound hypotention 2. edema 3. severe bronchospasm 4. pulmonary edema 5. cardiac arrhythmia 6. seizure 7. cardio- pulmanary arrest 8. death Question: A in shock may exhibit what symptoms?Answer: 1. tachycardia 2. , shallow breathing 3. cyanosis Question: What is SOLU-CORTEF?Answer: A brand name for hydrocortisone, which is a type of corticosteroid. May be used the treatment of anaphylactoid reacations to iodinated contrast materials. Question: What technical factors has a direct effect on dose?Answer: With no of image quality, reductions in mA and/or scan time(seconds). Question: Name the non-ionic media.Answer: 1. iopamidol (ISOVUE) 2. (omnipaque) 3. iopromide (ultravist) Question: What is ?Answer: Used to define the condition of breathing. Question: What factors may affect a 's calculated glomerular rate (GFR)?Answer: 1. age 2. sex 3. Question: What intravenous agent administration method provides the greatest overall plasma iodine concentration?Answer: Bolus Question: What is used to measure the patient dose from a CT exam?Answer: chamber Question: What is consent?Answer: the situation in which an assumption is made that an unconscious or otherwise physically unable patient consents to medical treatment. Question: What system component is for converting the digital signal into analog form?Answer: D to A Question: The reduction in of an x-ray beam as it interacts with matter is termed what?Answer: Question: A CT is formed in part by projecting back all of the attenuation values recorded during data acquistion onto what?Answer: Question: CT UrogramAnswer: A comprehensive, multi-phasic CT evaluation of the urinary tract. Consists primarily of pre-contrast, post-contrast & CT acquisitions through the kidneys, ureters, and bladder. It may also be commonly referred to as a CT-IVP. Question: Data system (DAS) Answer: The electronic components of a CT responsible for measuring the transmitted x-radiation absorbed by the detectors. Question: Data Answer: Pathaway of data transmission from the detectors to the computerized components of the system's data acquisition system. The number of data channels of a CT determines the maximum number of sections that may be acquired with each gantry rotation. Question: phaseAnswer: Period of peak arterial following the bolus IV administration of iodinated contrast material. For ex, the hepatic arterial phase occurs approx. 25-35 seconds after the initiation of contrast agent administration. Question: Answer: A form of noise on the CT image from errors during the measurement of transmitted radiationby the detectors. Question: Attenuation Answer: The assigned to an object quantifying its ability to attenuate an x-ray beam. Question: tube current modulation (ATCM)Answer: CT system software used to adjust the mA throughout an acquisition to reduce patient radation dose to a . Question: artifactAnswer: An error occurring in the superior portion of the , where dense bone averages with the low-attenuating brain tissue. This partial volume artifact may result in abnormally dense-appearing brain parenchyma. Question: CT consoleAnswer: Where instructional commands are entered by . Question: CT host Answer: Translate each command as it is entered into the systems machine . Question: CT scan Answer: Responsible for the timing & operation of the , gantry & high voltage generator. Question: DACAnswer: for converting the digital signal into an analog form. Question: High voltage Answer: Produces high potential that exists between cathode & anode. Question: AmplifierAnswer: Amplify's strength sent in analog form. Question: & hold (S/H)Answer: is sampled here 1st. Question: to digital converter (ADC)Answer: is digitized by ADC. Then stored temporarily in a raw data file. Question: ProcessorAnswer: Data calculated into an . Image is then transferred to host computer. Question: What does the slip ring ?Answer: *electrical power *scanning instructions *detected signals between stationary & rotating gantry components. Question: Name the benefits of multi-row CT.Answer: *faster scans *increased anatomical *scanning with thinner slices to improve resolution along the slice direction. Question: What is an electron beam CT (EBCT) .Answer: It is an design that has no x-ray tube. It offers very fast scan times making it suited for cardiac & coronary artery imaging. Question: What does the EBCT ?Answer: An electron beam that streams from its electron gun & which is -magnetically directed toward an array of tungsten anodes. An x-ray beam is generatred when the elctron beam strikes the anodes. Question: imagingAnswer: Is the comparison of 2 imaging modalities yielding co-registered . Question: There is great value in the PET image on the high-resolution CT image in order to what?Answer: la metabolism change with a specific structure. Question: The ________ _________ is the key point of interaction between the technologist & the imaging system.Answer: 's console Question: The ______ ______ is the primary link between the tech & the other components of the imaging system.Answer: Host Question: The spatial resolution of a CT can be improved by reducing what?Answer: size Question: Fourier (FT)Answer: a mathematical to convert distance into spatial frequency. Question: UniformityAnswer: to constant CT # of an object Question: CT spatial resolution can be by what 4 things?Answer: 1. using a smaller pixel 2. thinner slice imaging 3. narrowing the predetector collimation 4. increasing the source to distance. Question: Fourier transformation (FT)is a to:Answer: 1. transform object size to spatial frequency. 2. change distance into distance. Question: A Modulation Transfer function (MTF) can be used to what?Answer: spatial resolution at all spatial . Question: How is spatial resolution for CT expressed?Answer: By the value of the spatial frequency at a 10% modulation transfer (MTF). Question: Noise on a CT image principally what?Answer: contrast Question: is particularly important for what?Answer: bone mineral . Question: LinearityAnswer: is a property of a system, characterized by output that is directly proportional to the input. In CT, linearity describes the amount to which the CT # of a material is exactly proportional to the density of this material (in hounsfield ) |
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