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Semester 7 > CT review > Flashcards

CT review Flashcards

1
Q

main advantage of CT

A

the ability to differentiate small differences in density of anatomic structures and abnormalities and the superior quality of the images

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2
Q

spatial resolution

A

describes the ability of a system to define small objects distinctly

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3
Q

low-contrast resolution

A

refers the to ability of a system to differentiate on the image objects with similar densities

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4
Q

temporal resolution

A

refers to the speed at which the data can be acquired

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5
Q

z axis

A

refers to the thickness of the plane
determines the thickness of the slice
x=width
y=height

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6
Q

what is the most common matrix size in CT

A

512

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7
Q

attenuation meaning

A

the degree at which a beam is reduced

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8
Q

density

A

defined as the mass of a substance per unit volume

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9
Q

common CT number or HU

A

dense bone 3,000
muscle 50
white matter 45
gray matter 40
blood 20
cerebrospinal fluid 15
water 0
fat -100
lungs -200
air -1,000
* HU less than water are given a negative

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10
Q

positive contrats agents

A

material of higher density
barium sulfate and iodine

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11
Q

negative contrast agents

A

low density
water

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12
Q

artifacts

A

-objects seen on the image but not present on the object scanned

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13
Q

beam hardening artifact

A

result from preferential absorption of low energy photons which leaves higher intensity photons to strike the detector array
-commonly present at base of skull
-appear as dark streaks

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14
Q

volume averaging

A

process by which different tissue attenuation values are averaged to produce one less accurate pixel reading
aka partial volume effect
-small pixel size reduces the chances of volume averaging

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15
Q

step and shoot

A

in 1980s scanning system was a step and shoot.
-the tube rotated 360 around the patient acquiring a single slice. then the motion of the xray tube was stopped while the patient was advanced. this was repeated until desired areas was covered

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16
Q

helical(spiral) scanning

A

1990s
developed a system that eliminated the cables so there is continuous rotation of the gantry
-allows for uninterrupted data that traces a helical path around the patient

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17
Q

multidetector scanning

A

in 1992 scanners where introduced that contained two rows of detectors

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18
Q

data acquisition

A

data are acquired when xrays pass through a patient to strike a detector and are recorded

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19
Q

gantry

A

gantries vary in size as well as in diameter of the aperture with typical ranges being 70-90cm
-the gantry can be tilted
-slpi rings allow the gantry too rotate continuously making helical scan possible

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20
Q

generator

A

-high frequency generators are used and are located within the gantry
-the power capacity of the generator is listed in kilowatts(kW)
-

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21
Q

xray source

A

-CT tubes often contain more than one size focal spot
-smaller focal spot improve spatial resolution but concentrate heat into smaller portion can not tolerate as much heat
-anode heat capacity is measured in million heat units(MHU)
-anode that dissipation’s measure in thousand heat units(KHU)

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22
Q

filtration

A

-filters are used to shape the xray beam
-help reduce radiation dose to patient and help reduce image artifact
-bowtie filters: often used for the body, reduce beam intensity at the periphery of the beam corresponding to the thinner areas of the body
-collimators: restrict the beam and reduce scatter radiation, which improves contrast resolution and decrease patient dose
-source collimators: aka prepatinet collimator, affect slice thickness of the beam
-predetector collimators: act on the xray after it has emerged from the patient and before it strikes the detector

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23
Q

detectors

A

-collect information regarding the degree to which each anatomic structure attenuates the xray beam
-optimal characteristics of a detector:
-high detector frequency: ability of the detector to capture transmitted photons and change them to electronic signals
-low or no afterglow: brief, persistent flash of scintillation that must be taken into account and subtracted before image reconstruction
-high scatter suppression
-high stability
-made from solid state crystal or xenon gas filled chambers
-xenon gas are much less efficient but are less expensive, easier to calibrate and are highly stable
-solid state also called scintillation use crystal that fluoresces when struck by an xray photon, very efficient absorb almost 100% of the photons that reach them

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24
Q

detector
geometric efficiency of a detector

A

refers to the amount of space occupied by the detector collimator plates relative to the surface area of the detector

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25
Q

detector
capture efficiency

A

refers the to ability with which the detector obtains xray beams that have passed through the patient

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26
Q

detector
absorption efficiency

A

refers to the number of photons absorbed by the detector

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27
Q

detector
response time

A

time required for the signal from the detector to return to zero

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28
Q

detector
dynamic range

A

the ratio of the maximum signal measured to the minimum signal the detectors can measure

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29
Q

scanner generation
6 generations

A

1st generation: thin xray beam passed linearly over the patient and a single detector followed on opposite side of the patient.the tube and detector where then rotated slightly and process was repeated until 180 degrees was covered. NO LONGER USED
2nd generation: xray beam passed linearly across the patient before rotating, but with a fan shaped xray beam.NO LONGER USED
3rd generation: consist of an xray tube that produces a fan shaped bema that covers the entire field of view and a detector array.tube is focused on the detector array so collimation is available reducing scatter, disadvantage is frequent ring artifacts
4th generation: use a detector array that is fixed in a 360 circle within the gantry, the tube rotates within the detector array and produces a fan shaped beam. motion artifacts are an issue, will produce higher dose with same technique as 3rd generation
5th generation: aka electron beam CT(EBCT) or ultra fast CT, xray beam or detector moves
6th generation: aka dual source use two side by side tube detector arrays which can be energized using same or different kVp

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30
Q

detector electronics

A

-DAS data acquisition system measures the number of photons that strike the detector and converts the information to a digital signal and send the signal to the computer
-DAS is position in the gantry near the detectors
-ADC analog to digital converter converts the analog signals from the detector to digital format

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31
Q

image reconstruction terminology

A

image reconstruction: the process of manipulating data
-algorithm: is a precise set of steps to be performed in a specific order to save a problem
-reconstruction algorithms: used to convert information obtained from the detector array into information suitable fro image display
-fast Fourier transfrom(FTF) efficient algorithm that is used in image analysis
-interpolation: mathematical method of estimating the value of an unknown value using the known values on either side of the unknown

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32
Q

equipment components used for image reconstruction

A

-hardware is the portion of the computer that can be physically touched
-software is instructions that tell the computer what to do and when tot do it
-archiving: saving data on axillary devices for possible future viewing
-principle components of a computer are:
-input device
-output device
-central processing unit
-memory
- input device: feed data into the computer(keyboard, mouse, touch screen, CT mechanisms)
-output device: accept processed data from the computer(monitor, laser camera, printer)
-CPU central processing unit interprets computer program instructions and sequences tasks.
-CPU is made up of microprocessor, control unit, primary memory
-Types of memory
-ROM(read only memory)
-RAM(random access memory)
-WORM(write once read many)-saved memory cannot be rewritten, erased, reformatted or

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33
Q

data types

A

-raw data: includes all measurements obtained from the detector array, aka scan data
-prospective reconstruction: image reconstruction automatically produced during scanning
-retrospective reconstruction: the same raw data is used later to generate a new image
-image data: those that result once the computer has processed the raw data and displayed an image

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34
Q

terminology

A

-ray: the path the xray beam takes from the tube to the detector
-ray sum: measurement of how much the beam is attenuated
-view: complete set of ray sums
-attenuation profile:eh system accounts for the attenuation properties of each ray and correlates them with the position of the ray
- back projection: process of converting the data from the attenuation profile to a matrix
-convolution: process of applying a filter function to an attenuation profile
-Scan Field of View(SFOV)determines the area within the gantry from the raw data are acquired
-DFOV(display field of view) determines how much of the raw data is used to create an image

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35
Q

display monitors

A

-output device allows the information stored to be displayed
-the output device is usually a cathode ray tube(CRT) or some form of flat panel like a TFT LCD, or LED
-DAC convert the anaolg signal to digital signal

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36
Q

cameras

A

-multiformat cameras transfer the image displayed on the monitor to film
-laser cameras bypass the image on the display monitor and transfer the data directly form the computer which improves image quality

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37
Q

gray scale

A

-there is 2000 different Hounsfield Units but monitor can only display about 1024 shades
-the human eye can only differentiate typically fewer than 40 shades of gray
-window width determines the number of hounsfield units assigned to each level of gray
-0 hounsfield units=water
- -1000 hounsfield units=air
-1000 hounsfield units=dens material like bone
-lower values are darker shades
-higher values are lighter shades

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38
Q

window width

A

-determines the HU represented on a specific image
-selects the quantity of HU to be displayed as shoes of gray
-values high than selected range appear white
-values lower than selected range appear black
-increasing window width=more numbers assigned to each shade of gray
-wide window widths are best for imaging tissue types that vary
-narrow window width is used for tissue with similar densities
-manipulation of window width and window levels referred to as windowing

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39
Q

window level

A

-selects the center CT value of the window width
-slects which HU are displayed on the image

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40
Q

how to determine the range
if the window width is 300
window level is 200

A

divide window within half: 300/2=150
subtract that from the window level: 200-150=50 which is the lower limit

to calculate ether upper limit
150+200=350

therefore the gray scale range is 50 to 350

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41
Q

ROI

A

-region of interest
-defining an area of interest
-place a circle over a area of concern/interest to get the average HU of that area
-if a ROI is placed over an area the reading is the average for al the pixels within that ROI

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42
Q

standard deviation

A

-factors that produce high standard deviation include
1.mixed attenuation tissue within the ROI(calcium within the organ)
2.ROI includes a streak artifact
3.ROI that is not inside the margins of an object being measured (kidney cyst measured with adjacent renal calyx)

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43
Q

reference image

A

-displays the slice ;Ines on corresponding locations on the scout image
-helps localize slices according to anatomic landmarks

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44
Q

image magnification

A

-uses only image data and does not improve resolution
-simply makes the existing image bigger
-often used when acquiring distance measurements or placing a ROI

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45
Q

histogram

A

graphical display showing how frequently a range of CT number occurs within a ROI

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46
Q

common window settings

A

head
posterior fossa: ww:150,WL:40
brain:ww;100,WL30
temporal bone;WW;2,800,WL:600
neck:WW:250,WL30
chest
mediastinum:WW;350,WL:50
lung WW:1500,WL:-600
abdomen
soft tissue:WW:350,WL:50
bone:WW;1800,WL:400
spine
soft tissue:WW:250,WL:50
bone:WW:1800,WL:400

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47
Q

localizer scans

A

-aka: scout,surview,topogram,scanogram,preview, pilot
-created while the tube is stationary and the table moves through the scan field
-structures appear superimposed like conventional radiography
-the position of the tube determines the orientation of the image: if the tube is above the patient the localizer scan will be AP
-miscentering the patient in either direction can result in out of field artifact
-some protocols it is impossible to use the scout image for landmarks and in that case there are 2 things that can be done
1.one cross sectional slice is taken and checked for accuracy
2.additional cross sectional slices are included superiorly and inferiorly of the estimated location

48
Q

step and shoot scanning

A

-the CT table moves to the desired location and remains stationary while the xray tube rotates within the gantry collecting data
-aka axial scanning, conventional scanning, serial scanning, or sequence scanning
-clustering: grouping more than one axial scan in a single breath hold
-disadvantage: cumulative effect of the inter scan delay adds to total exam time. also axial data has more limitations regarding reconstruction options than do data acquired with helical methods
-slice misregistration occurs when a patient breathes differently with each data acquisition

49
Q

single detector row systems

A

-SDCT the largest allowable slice thickness is less than the detector width typically 10mm
-the radiation emitted from the xray source is referred to as a fan beam
-each gantry rotation produces data for a single slice

50
Q

multi detector row systems

A

-in MDCT a single rotation can produce multiple slices
-MDCT have increased the sped of gantry rotation which further increases volume coverage per unit time
-MDCT can be used for either axial or helical data acquisition
-some MDCT systems the detectors in the center are thinner than those at the periphery. this is called adaptive arrays, nonuniform arrays, hybrid arrays
-binning a process in which data from multiple parallel rows of detector elements can be combined
-EX: 16 detector rows, 1.25mm wide can be combined in the following:
-4 slices each 1.25mm
-4 slices, each 1.25mm(grouping 2 detector rows for each slice)
-4 slices, each 3.75mm(grouping 3 detector rows for each slice)
-4 slices each 5mm(using all the available detectors groups of 4)

51
Q

dual source CT

A

-uses two sets of xray tubes and two corresponding detector arrays in a single CT gantry
-goal is to increase scan speed
-the two xray tubes can be programmed to use different kVp settings while working simultaneously

52
Q

dual energy CT

A

-aka spectral imaging refers to any acquisition of CT data at two different kVp settings

53
Q

helical scanning

A

-3 basic ingredients define a helical scan process;1.continualy rotating xray tube, 2. constant xray output,3.uninterupped table movement
-aka spiral, volumetric,continous acquisition scanning
-advantage: ability to optimize iodinated contrast agent administration, reduction of respiratory misregistration, and reduction of motion artifacts from organs such as the heart
-major improvements that led to the development of helical scan methods are:
-gantries with slip ring design
-more efficient tube cooling
-higher xray output
-smoother table movement
-software that adjusts for table motion
-improved raw data management
-more efficient detectors
-in helical scanning the beginning point of the slice is not win the same plane as the end point(think of it like a spring)
-helical interpolation methods create images that closely resemble those acquired in a traditional axial mode “unslant” the slice

54
Q

pitch

A

-used to describe the table movement during a helical scan
-defined as travel distance of the table per 360 rotation divided by xray beam collimation width
-when pitch is less than 1 scan overlap occurs
-as pitch increases fewer data is acquired for each table position
-increasing pitch results in a scan covering more anatomy lengthwise for a given total acquisition time, while reducing dose.

55
Q

scanning parameters

A

-factors that affect the quality of the image. can be controlled by the operator
-include mA, scan time, slice thickness, filed of view, scan algorithm, kVp, pitch for helical scan

56
Q

mAs

A

-mA and scan time together define the quality of the xray energy
-mA and scan time is mAs
-increasing mA increases the number of electrons that will produce xray photons
-scan time is the time it takes for the gantry to make a complete 360 rotation
-mAS is the quantity of xrays produced
-higher mAs allow shorter scan times to be used
-reducing mAs while keeping kVp constant reduces the dose to the patient

57
Q

kVp

A

-tube voltage
-the quality of the beam
-more limited choices usually fixed at 120
-increasing kVp increases the intensity of the beam and its ability to penetrate a thick dense part
-adult body scan usually done at 120kVp, paediatric body scan done at 20 kVp

58
Q

uncoupling effect

A

-the image quality is uncoiled form the dose so when a high mAs or kVp is used a good image still results

59
Q

Field of View

A

-SFOV determines the area within the gantry for which raw data are acquired
-DFOV determines how much of what section of the collected raw data are used to create an image

60
Q

slice thickness

A

-impacts image quality
-thinner slices produce sharper images

61
Q

reconstruction algorithm

A

-determine how data are filtered in the reconstruction process
-some algorithms help reduce the appearance of artifacts by reducing the difference between adjacent pixels but as a result sacrifice spatial resolution-often called smoothing algorithms
-some filters accentuate the difference between neighbouring pixels to optimize spatial resolution-often called bone or detail filters

62
Q

iterative reconstruction

A

-IR refers to image reconstruction algorithms that begin with an assumption and then improve the image by continually analyzing scan data and making adjustments
-valuable for its ability to enhance image quality for lower dose scans

63
Q

scan geometry

A

-a partial scan is when images are created from less than 360 degree rotation, typically 180 plus degree of arc of the fan angle-aka half scans
-overscan uses information from more than 360 rotation

64
Q

image quality

A

-comparison of the image to the actual object
-in CT is directly related to its usefulness in providing an accurate diagnosis
-image accuracy aka image fidelity
-the two main features of image quality that can be measured are
1.detail(high contrast) resolution; the ability to separate objects
2.contrast resolution; the ability to differentiate between objects with very similar densities as their background

65
Q

spatial resolution

A

-aka detail resolution
-systems ability to resolve as separate forms, small objects placed very close together
-can be measured directly using line pair phantom
-can be calculated from analyzing the spread of information within the system
-line pair phantom is lead strips placed in acrylic
-number of line pairs visible per length is also called spatial frequency(the frequency an object will fit into given space)
-MTF is most commonly used method of describing spatial resolution ability
-MTF is the ratio of the accuracy of the image compared with the actual object scanned
-CT ha significantly worse spatial resolution

66
Q

factors affecting spatial resolution
matrix,DFOV,pixel size, slice thickness

A

-matrix size and DFOV section determine pixel size
-the greater the total number of pixels the smaller each individual pixel is
-DFOV determines how much raw data will be used to reconstruct the image
-increasing the DFOV increases the size of each pixel
-thin slices result in near isotropic voxels(cube shape-measure same all around)

67
Q

reconstruction algorithms

A

-some will smooth the data more heavily by reducing the difference between adjacent pixels
-some accentuate the difference between neighbouring pixels to optimize spatial resolution-often called bone or detail filters

68
Q

focal spot size

A

larger focal spot size cars more unsharpness and reduce spatial resolution

69
Q

contrast resolution

A

-aka low contrast resolution
-is the ability to differentiate a structure that varies only slightly in density from its surrounding
-CT is superior in all modalities for contrast resolution

70
Q

noise

A

-grainy appearance on under exposed images
-major cause of noise is quantum mottle-occurs when there is insufficient number of photons detected
-SNR-the number of xray photons detected per pixel

71
Q

factors affecting contrast resolution

A

-mAs
-doubling mAs increase SNR by 40%
-mAs will improve contrast resolution but will also increase dose
-thicker slices allow more photons to reach the detector and therefore have a better SNR and appear less noisy
-bone algorithms produce lower contrast resolution
-soft tissue produce higher contrast resolution

72
Q

temporal resolution

A

-how rapidly data are acquired
-controlled by gantry rotation speed, number of detector channels in the system, speed which the system can record changing signals -important in imaging moving structure and dynamic flow of contrast

73
Q

quality assurance

A

-design to ensure that the CT system is producing the best possible quality image
-technologist typically perform and record routine quality control tests
-medical physicist obtains dosimetric data
-three basic concepts the program is designed by
1.the tests that make up the program must be performed on a regular basis
2.the results from all the tests must be recorded using consistent format
3.documentation should indicate whether the tested parameter is within specified guidelines

74
Q

quality control phantoms

A

-line pair phantom: used to measure spatial resolution directly. Usually done MONTHLY
-phantom with objects of varying sizes that have a small density difference between their background is used for contrast resolution: usually done MONTHLY
-slice thickness: phantom contains includes a ramp, spiral and wedge.done SEMIANNUALLY
-laser light accuracy: done SEMIANNUALLY
-image noise: water phantom is used” done WEEKLY
-cross field uniformity: the ability of the CT scanner to yield the same CT number in a homogeneous object. several ROIS are placed around the phantom and are expected to have the same measurement. done WEEKLY
-linearity refers to the relationship between CT numbers and their liner attenuation values of the scanned object at a designated kVp value.daily calibrations help reduce fluctuations
-linearity a phantom with objects of known densities is scanned and the objects are measured. done SEMIANNUALLY

75
Q

image artifacts

A

-can be classified as:
-physics based-physical process associated with data acquisition
-patient based
-equipment induced
-beam hardening artifacts: result when lower energy photons are absorbed leaving the higher energy photons to strike the detector
-occurs more with dense objects
-cupping or streak artifact
- to avoid beam hardening best thing is to select to correct SFOV
-partial volume artifact: dense object lines to the edge of the FOV. causes shading, can be reduced by using thinner slices
-undersampling: occurs when there is not enough information collected during acquisition- results in aliasing artifact which is stripes come form a dense object
-can be reduced by increasing scan time or by reducing helical pitch
-edge gradient: streak artifact arising from irregular shaped object that have a different density then surroundings
-patient motion artifact: shading, streaking, blurring or ghosting
-out of field artifacts: caused by anatomy that extends outside the selected SFOV
-ring artifacts: mostly with third generation scanners, appear as a ring or multiple rings, caused by faulty or miscalibrated detector elements
-tube arcing: caused by an electrical current surge, slight streaks that are barley noticeable or opposite that the image is useless
-windmill artifacts: appear on MDCT helical system the beam becomes more coned shaped, streaks or brightness and dark shading near large density difference areas

76
Q

retrospective reconstruction

A

-reconstructing raw data to create images only done from he operators console
-DFOV,image center and reconstruction algorithm can be changed retrospectively

77
Q

image reformation

A

-aka image rendering
-in order to reformat all the source images must have identical DFOV, image center, gantry tilt, and must be contiguous
-only uses image data
-the thinner the original slice step better the reformatted image

78
Q

multiplanar reformation(MPR)

A

-reformations done to show anatomy in various panes
-2D
-can be created in coronal, sagittal or oblique planes
-scanner created MPRs are programmed into the system to be generated automatically
-manual MPR require the operator to input the criteria
-if MPRs are to be created form PACS the thinnest possible slices must be used

79
Q

3D reformation

A

-attempts to represent the scan volume in a single image
-can be done on independent consoles
-draw an imaginary line from the viewer through the data volume

80
Q

surface rendering

A

-aka shaded surface display(SSD)
-creates the outline or shell of a structure
-useful for examining tubular structures like airways, colon and blood vessels

81
Q

Maximum intensity projection(MIP)

A

-selects only the highest value voxel from the data set for display

82
Q

Minimum intensity projection(MinIP)

A

-selects the minimum value voxels for display

83
Q

volume rendering

A

-3D transparent representation of the imaged structure
-all voxels contribute to the image

84
Q

end-liminal imaging

A

-form of VR that is specifically designed to look inside the lumen os a structure
-aka virtual endoscopy

85
Q

Region of interest Editing

A

-process of selectively removing or isolating information from the data set
-aka segmentation
-purpose is to better demonstrate the area of interest by removing obscuring structures

86
Q

HIE

A

Health Information Exchange
-allows healthcare providers and patients to appropriately access and securely share a patients vital medical information

87
Q

Informatics

A

-the collection, classification, retrieval and dissemination of recorded information
-HIS hospital information system: focus on administrative issues such as patient demographic data, financial data, patient location within the hospital
-CIS clinical information system: keep track of clinical data
-CPOE:computerized physician order entry: systems electronically transmit clinician orders to radiology and other departments
-EHR: digital record electronic health record
-EMR:electronic medical records
-RIS: used for scheduling patients, string reports, patient tracking, protocoling exams, and billing
-PACS: rings of technologies necessary for the storage, retrieval, distribution and display of images
-

88
Q

two key components form the information infrastructure in the radiology department

A

1.RIS:radiology Information System
2.PACS:picture archive communication system

89
Q

what form must images be in to be included in PACS

A

digital format
digital format also known as soft copy

90
Q

networking

A

-networking is a group of two or more computers linked together
-LAN: local area network, computer networks that are close together(in the same building)
-WAN:wide are networks, farther apart and connected by telephone lines, cables or radio waves
-“wired”-are those linked by physical connection
-“wireless”-use radio waves to transmit data between computers
-servers essential to the functioning of PACS are called core servers
-bandwidth: is the capacity of the network connection
-lossless: compressing image data with no image data lost during the process
-lossy: compressing image data but artifacts are introduced

91
Q

DICOM

A

-Digital Imaging Communication in Medicine

92
Q

workstation monitors

A

-in 19990 all monitors were CRT(cathode ray tube)
-recently LCD(liquid crystal display) is used
-LCD cost 2-3 times more than CRT, but they have a longer life span and consume less energy
-quality assurance is simpler with LCD

93
Q

how many patient identifiers are required

A

at least 2

93
Q

Data storage

A

-classified as online:when images are instantly accessible
-classified as near line: when images are automatically retrieved from a storage system
-offline: when image devices must be located and manually loaded into the system
-optical jukebox; robotic storage systems that automatically load and unload the optical discs

94
Q

pre exam questions

A

-questions about renal function, allergies or hyperthyroidism should be asked by the technologist prior to the exam to ensure the patient is safe to receive contrast

95
Q

lab values for CT

A

-eGFR(glomerular filtration function)
-serum creatinine
-blood urea nitrogen(BUN
-provide information about a patients kidney function
-normal eGFR is greater than 60mL/min/1.73m^2
-normal range for BUN is 7-25mg/dL
-normal range for serum creatinine is 0.6 to 1.7mg/dL

96
Q

lab values for biopsies

A

-prothrombin time(PT)
-partial thromboplastin time(PTT)
-platelet count
-normal PT is 11-14 seconds
-normal PTTis 25-35 seconds
-normal platelet count is 150,000 to 400,000

97
Q

patient education and consent

A

-at a minimum the technologist should describe:
-how the procedure is carried out
-the approximate time the procedure will take
-if there is contrast given
-what is expected of the patients
-if there is any necessary follow up

98
Q

consent

A

-basic consent is explaining to the patient what you are going to do and asking if they agree
-many times a consent form is signed by the patient especially when contrast is given
-consent form must be signed by the patient before any pain medications or sedatives are given that can alter there state of mind
-paediatric patients a parent or legal guardian can sign the consent form

99
Q

immobilization devices

A

-used for patient safety and to improve image quality
-when possible basic consent should be given to use the devices
-when restraining devices are used must adhere to:
-patient must be Allowed as much mobility as is safe
-the areas of which the body are immobilized must be padded to prevent injury
-normal anatomic position must be maintained
-knots that become tighter when moved are prohibited
-immobilzer must be easy to remove quickly
-circulation or respiration cannot be impaired
-if leg immobilizers are used wrist ones must be used al well to prevent them removing them

100
Q

vital signs

A

-body temperature
-pulse
-respirations
-blood pressure

101
Q

body temperature

A

-can be taken by placing thermometer in mouth, ear(tympanic), axilla or rectum
-oral, rectal and tympanic are higher than axilla
-temporal artery sweep a small scanner across the forehead then behind the patient ear

normal oral:96.8-100.4F, average 98.7F
normal rectal: 97.2-100.8F, average 99.1F
normal axillary: 95.8-99.4F, average97.7F
temporla artery: 97.2-100.8F, average 99.1F

102
Q

pulse locations

A

common places to feel pulse
-temporal pulse:just anterior to ear: superficial temporal artery
-facial pulse:lower margin of mandible, about 1/3 anterior to angle (facial artery)
-carotid pulse: along anterior aspect of neck(carotid artery)
-radial pulse: at the thumb side of wrist)radial artery)
-brachial pulse: on medial side of elbow cavity between the biceps and triceps muscle(brachial artery)
-femoral pulse:in the groin(femoral artery)
-popliteal pulse: behind the knee(popliteal artery)
-pedal pulse:posterior ankle, behind medial malleolus(tibias posterior artery)
-pedal pulse; top of foot(dorsals pedis artery)

103
Q

average pulse

A

-adult 60-100 beats pe rminute
-athletic adults 45-60 beats per minute
-child 95-110 beats per minute
-infants 100-160 beats per minute

104
Q

respirations

A

-number of breaths a person takes per minute
-adults:14-20
-adolescent youth:18-22
-children: 22-28
-infants: 30 or more

105
Q

blood pressure

A

-measured by a sphygmomanometer in mmHg
-systolic is peak pressure top number
-diastolic is lowest pressure bottom number
-healthy adult: 120/80
-hypertension: blood pressure that is abnormally high
-hypotension: blood pressure that is abnormally low
-normal range for adults: 90-140/60-90
-normal range for children: 65-130/45/85

106
Q

Sinuses CT

A

-intended as an inexpensive accurate and low radiation dose method for confirming the presence of inflammatory synodal disease
-can be done with IV or without
-reoccurring sinuits is done without

107
Q

Head CT
Brain

A

begin at the base of the skull and continue superiorly

108
Q

temporal bones

A

-organs of hearing and balance are located in the petrous ridges of the temporal bones
-thin slices are used as these organs are tiny
-coronal and axial planes

109
Q

neck CT

A

-usually done with IV contrast unless contraindicated
-often times artifacts caused by dental work obscure the surrounding structures

110
Q

Spine CT

A

-usually done without Iv contrast

111
Q

chest CT

A

-routine chest protocol includes both soft tissue and lung windows
-apices to under the diaphragm

112
Q

abdomen pelvis CT

A

-include the entire liver and other organs

113
Q

wrist

A

-the orientation when doing, elbows, wrist, forearms and hands can become confusing so often times a marker is used to help

114
Q

knee

A

most Ct of the knee extend from the distal femur to beyond tibial plateau
-both knees are included in the scan field of view only the targeted knee is included in the display field of view

115
Q
A

Semester 7 (4 decks)

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