All The Things... Flashcards
(228 cards)
1
Q
If kVp is increased without adjusting any other factors, what happens to patient dose?
A
patient dose increases
2
Q
If kVp is increased and there is an accompanying decrease in mAs, what happens to patient dose?
A
patient dose decreases
3
Q
What is the best method of using exposure factors to reduce patient dose?
A
selection of the highest kVp consistent with image quality
4
Q
Decreasing mAs does what to patient dose?
A
decreases patient dose
5
Q
If mAs is increased and kVp is decreased, what happens to patient dose?
A
patient dose increases
6
Q
Which of the following would crease the least amount of patient exposure?
A. 68 kVp @ 25 mAs
B. 80 kVp @ 12.5 mAs
A
B. 15% increase in kVp and cutting mAs in half decreases patient dose
7
Q
The use of specific area shielding is warranted when?
A
any time a radiosensitive organ or tissue is in or near the useful beam (gonadal, breasts)
8
Q
What is the most common area shielded?
A
gonadal
9
Q
What is the most important area to shield?
A
gonadal
10
Q
What are the three rules for gonadal shielding?
A
- should be used on all potentially reproductive aged patients
- used when radiosensitive areas lie in or near the primary beam
- used in accompaniment with collimation and careful positioning
11
Q
What are the two general types of shields?
A
- shadow
2. contact
12
Q
What are some shielding items (protective apparel) used in this field?
A
apron gloves thyroid collar goggles movable walls gonadal shields
13
Q
What are the parameters that are used to determine if a radiosensitive area is close enough to the primary beam to require shielding?
A
within 2 inches or 5 cm of the primary beam
14
Q
When used properly, what two things can beam restriction do?
A
reduce patient dose and improve image quality
15
Q
In what two ways does proper collimation help to reduce patient exposure?
A
- reduces the volume of tissue directly irradiated
2. reduces the amount of scatter radiation
16
Q
What are the 3 types of beam restricting devices?
A
- Aperture diaphragm
- Cones/cylinders
- Collimators
17
Q
What is the most common beam restrictor used?
A
Collimation
18
Q
What is Positive-Beam Limitation (PBL)?
A
when the collimator automatically adjusts the beam to the size of the IR being used
19
Q
Between what years was positive beam limitation required on all equipment?
A
1974-1994
20
Q
The positive-beam limitation (PBL) must be accurate to within what percentage of the SID?
A
2%
21
Q
What are two groups of digital radiography reusable detectors?
A
- Cassette-based (indirect digital-CR)
2. Cassette-less (direct digital-DR)
22
Q
Define photo-stimulable phsophor
A
rigid sheets with several layers that are designed to record and enhance transmission of the image from a beam of ionizing radiation
23
Q
What are the two types of photo-stimulable phosphor imaging plates used in CR cassettes?
A
- turbid phosphor
2. structured phosphor (needle)
24
Q
Cassette-less systems (DR) include a photo-stimulable storage phosphor and what other two things?
A
Flat-panel and CCD (Charged-coupled device)
25
What are the two types of flat panel detectors?
direct and indirect
26
What are flat panel detectors?
an array of millions of detectors that are usually built into the bucky
27
Each square in the matrix of a flat panel detector is called what?
a detector element (DEL)
28
What do the detector elements (DEL) do?
collect the electrons given off by amorphous selenium or silicon
29
Define direct acquisition
directly converts the incoming x-rays into an electronic signal (x-rays to electrons)
30
What do direct capture detectors utilize as a detector?
amorphous selenium
31
Define indirect acquisition
a two-part process that first converts x-rays to light then converts the light into electrons
32
Indirect acquisition requires what two components?
a scintillator and a photodetector
33
What kind of scintillator do indirect acquisition systems utilize to convert x-rays into visible light?
cesium iodide
34
Indirect acquisition systems use what to convert the light into an electronic signal?
amorphous silicon
35
What does a scintillator do?
converts incoming x-ray photons to light
36
What does a photodetector do?
converts light into an electronic signal
37
What is the thin film transistor (TFT)?
a complex circuit device that collects electrons emitted from either amorphous selenium or amorphous silicon
38
PSP plates should be erased how often if they have not been used?
every 48 hours
39
Should electronic collimation be used in place of beam restriction?
Hellz no
40
What does the look-up table (LUT) do?
converts raw data from digital signal to different numbers to determine the contrast in an image
41
Define histogram
they graphically represent a collection of exposure values extracted from the receptor
42
The predetermined values used to create an image are known as what?
the values of interest
43
Automatic rescaling permits what?
the consistent output of image data and image display appearance even when errors in exposure technique are present
44
What are the two classifications of digitized image filters?
high-pass (edge enhancement)
| low-pass (smoothing/noise-suppression)
45
High-pass filtering (edge enhancement) either amplifies or deletes all but what frequencies?
all but the high frequencies
46
Edge enhancement or high-pass filtering is also referred to as what?
sharpening
47
Low-pass filtering (smoothing/noise suppression) either amplifies or deletes all but what frequencies?
all but the low frequencies
48
Contrast in digital radiography is controlled by what?
the look-up table selected from the menu
49
Define ghost image
an image from a previous exposure caused by imaging plate not being completely erased
50
Define banding artifact
alternating light/dark strips caused by transport of the imaging plate through the CR reader in the slow scan direction
51
Define dark noise
the noise on an unexposed image due to improper erasure of the plate reader
52
Define dead pixels
a flat-panel detector that has detectors not functioning correctly
53
What are readout problems
malfunction of the reader due to lack of proper calibration of exposure indicators, laser function, and throughput
54
What are the components of a CR plate reader?
read area
erasure area
plate or light collecting system moves
55
Nasogastric tubes are also called?
NG tubes
56
Nasogastroc tubes are made of what?
silicone or rubber
57
Where are nasogastric tubes inserted?
into the stomach, duodenum, and jejunum
58
What is the purpose of a nasogastric (NG) tube?
to keep the stomach free of gastric contents and air, aids in healing process before and after surgery
59
Nasoenteric tubes are also called?
NE Tubes
60
Nasoenteric tubes are allowed to pass into the small intestine how?
by peristalsis
61
What are nasoenteric tubes used for?
to aid patients who are unable to obtain nourishment or take oral medications
62
What is a gastronomy tube?
a surgical opening into the stomach
63
Where is a gastronomy tube placed?
the tube is attached to the wall of the stomach
64
What is a gastronomy tube used for?
the purpose of feeding the patient
65
What are implanted ports used for?
patients with long term medication administration, frequent blood transfusions or blood draws, and parenteral nutrition
66
What are the two most common types of central venous catheters?
1. Hickmann
| 2. Broviac
67
Central venous catheters are also called?
PIC lines
68
What are central venous catheters used for?
long-term medication or transfusion on patients with a long-term illness
69
Where are central venous catheters planted?
in the top right side of the chest
70
What is a tracheostomy?
an opening in the trachea created surgically to relieve respiratory distress
71
What are endotracheal tubes used for?
to establish or open the airway
72
Where are endotracheal tubes placed?
through the mouth and into the trachea
73
If an endotracheal tube is placed too high, what can happen?
push air into the stomach
74
If an endotracheal tube is placed too low, what can happen?
can cause a lung to collapse
75
When is a chest tube needed?
when there is air in the pleural cavity which can cause a lung to collapse (pneumothorax)
OR
blood of fluid are accumulating in the lung (hemothorax)
76
Where should chest tube containers be placed?
Below the chest at all times
77
What are the 3 most common tissue drains?
1. Hemovac
2. Jackson-Pratt
3. Penrose
78
What are tissue drains used for?
placed at or near a wound site/operative site if a large amount of drainage is expected
79
What are T-tubes used for?
to collect bile
80
How many bones are in the body?
206
81
What does the circulatory system do?
distributes oxygen to the cells and transports waste products from cells
82
What does the digestive system do?
absorption and elimination
83
What does the respiratory system do?
supplies oxygen and eliminates carbon dioxide
84
What does the urinary system do?
Regulates the blood and eliminates waste products
85
What does the nervous system do?
regulates body activities
86
What does the muscular system do?
allows for movement; skeletal, visceral, and cardiac types of muscles
87
What does the endocrine system do?
it is the ductless glands of the body and it regulates the body via hormones
88
What does the integumentary system do?
protects the body and eliminates wastes through perspiration
89
How many bones are in the axial skeleton?
80
90
What bones are included in the axial skeleton?
skull, vertebrae, ribs, sternum
91
How many bones are in the appendicular skeleton?
126
92
What bones are included in the appendicular skeleton?
the limbs, shoulder, and pelvic girdle
93
What are the 4 classifications of bones?
1. long
2. flat
3. short
4. irregular
94
What bones are considered long bones?
the bones of the limbs
95
What bones are considered short bones?
Carpal and tarsal bones
96
What bones are considered flat bones?
ribs, sternum, scapulae
97
What bones are considered irregular bones?
vertebrae, facial bones, pelvic bones
98
What are the 3 structural joint classifications?
1. synovial
2. cartilaginous
3. fibrous
99
What are the 3 functional joint classifications
1. synarthrodial
2. amphiarthrodial
3. diarthrodial
100
What are the 7 movement types of synovial joints?
1. plane (gliding)
2. ginglymus (hinge)
3. trochoid (pivot)
4. ellipsoid (condyloid)
5. sellar (saddle)
6. spheroidal (ball and socket)
7. bicondylar
101
How does the sagittal plane cut the body?
in half left to right
102
How does the coronal (frontal) plane cut the body?
in half front and back
103
How does a horizontal (transverse, axial) plane cut the body?
in top and bottom sections
104
Define ventral surface
anterior surface
105
Define dorsal surface
posterior surface
106
Define filtration
the process of eliminating undesirable low-energy x-ray photons by the insertion of absorbent materials into the primary beam
107
What is the primary reason for the use of filtration?
to eliminate photons that would increase dose to the patient but not enhance the image
108
Filtration is called doing what to the beam?
hardening of the beam
109
What does filtration do to the average beam energy?
increases the beam energy (beam quality and penetrability)
110
Based on NCRP report #102, what is the minimum total filtration level recommended for a machine operating below 50 kVp?
0.5mm Aluminum
111
Based on NCRP report #102, what is the minimum total filtration level recommended for a machine operating between 50 and 70 kVp?
1.5 mm Aluminum
112
Based on NCRP report #102, what is the minimum total filtration level recommended for a machine operating over 70 kVp?
2.5 mm Aluminum
113
AEC stands for what?
automatic exposure control
114
What does AEC do?
eliminates the need for the radiographer to set an exposure time, shuts off the exposure when enough radiation has reached the IR
115
What are a few main ways to help reduce exposure in pediatric patients?
- minimize repeat exposures
- utilize higher speed film/screen combos
- use appropriate shielding
- use immobilization devices and shorter exposure times when possible to reduce motion
116
What does ALARA stand for?
As Low As Reasonably Achievable
117
ALARA follows what type of dose-response relationship?
linear, non-threshold
118
We comply with ALARA because we must always assume what about any dose of radiation?
any dose, regardless of size, produces a response
119
What are 4 important ways ALARA can be achieved?
1. always wear personnel monitoring devices
2. restraint devices when possible vs. us holding
3. close collimation, filtration, minimal repeats, high kVP
4. follow the 3 cardinal principles of radiation protection
120
What are the 3 cardinal principles of radiation protection?
time
distance
shielding
121
What does tomography do?
utilizes the motion of x-ray tube and image receptor to blur unwanted structures above and below the plane of interest
122
What is the fulcrum in tomography?
the pivot point around which the motions of the tube and image receptor are centered
123
What determines the focal plane and section level in tomography?
the fulcrum
124
What is a fixed fulcrum?
when the patient moves up and down to change level
125
What is an adjustable fulcrum?
when the patient is stationary and the machine moves up and down to change level
126
What is the focal plane in tomography?
the area in which the image exhibits satisfactory recorded detail
127
How do objects closer to the fulcrum appear?
less blurred
128
How do objects further from the fulcrum appear?
more blurred
129
The focal plane in tomography may also be referred to as what?
section, section level, layer height, object plane, and depth of focus
130
What is the section thickness in tomography?
the width of the focal plane which is controlled by the exposure angle
131
What is the section interval in tomography?
the distance between fulcrum levels
132
What is the tomographic amplitude?
the total distance that the tube travels, including the travel without exposure
133
What type of relationship is there between the tomographic amplitude and the section thickness?
an inverse relationship
134
What is the exposure amplitude?
the total distance that the tube travels ONLY during the exposure
135
Is the exposure amplitude less, equal to, or more than the tomographic amplitude?
always less or equal to
136
What determines the thickness of the tomographic cut?
the exposure amplitude
137
If there is a wider exposure amplitude (angle, arc), what happens to the cut?
thinner cuts
138
If there is a narrower exposure amplitude (angle, arc), what happens to the cut?
thicker cuts
139
What is the blur in tomography?
the streaking or smearing that results in the loss of nearly all recorded detail of objects outside of the focal plane
140
What are the 5 motions that blurring patterns are determined by?
1. linear
2. circular
3. elliptical
4. hypocycloidal
5. spiral
141
What is the primary use of tomography?
nephrotomography
142
Define luminance
the brightness of a monitor display
143
Define pixel size
measure from side to side of the pixel
144
Define pixel pitch
measure from the center of one pixel to the center of an adjacent pixel
145
What are the two ways to measure pixels?
pixel size and pixel pitch
146
What characteristics affect spatial resolution in cassette based systems?
sampling frequency, receptor size, and phosphor thickness
147
For cassette-less systems, spatial resolution depends on what?
the detector element size? (DEL)
148
DEL stands for what?
detector element size
149
If you increase the DEL size, what happens to the spatial resolution?
it decreases
150
The scale of contrast is referred to as what in digital radiography?
gray scale
151
Is the dynamic range for digital imaging smaller or larger than film?
larger
152
The number of shades of gray reached is determined by what?
gray scale bit depth
153
What is the formula to calculate bit depth?
2^n where "n" is the number of bits
154
8 bits would equal what bit depth/how many shades of gray?
256 shades of gray (2^8)
155
10 bits would equal what bit depth/how many shades of gray?
1,024 shades of gray (2^10)
156
Define window level
describes the digital processing that produces changes in density/brightness
157
Define window width
accurately describes the digital processing that produces changes in gray scale or contrast level
158
What are the 4 main vital signs used?
1. temperature
2. pulse
3. respiration
4. blood pressure
159
What is the average oral temperature of an adult?
98.6 F or 37 C
160
What is the average axillary temperature of an adult?
97.6 F or 36.4 C
161
What is the average rectal temperature of an adult?
99.6 F or 37.5 C
162
What is the average temperature of an infant (3 months to 3 years)?
99 F or 37.2 C
163
What is the average temperature of a child (5 years to 13 years)?
97.8 F (36.7 C) to 98.6 F (37 C)
164
What are the symptoms of a fever?
```
increased pulse and respiratory rate
discomfort and aching
flushed dry skin
chills
loss of appetite
```
165
A person who has a high body temperature above normal limits is said to have what?
pyrexia
166
A person who has a low body temperature below normal limits is said to have what?
hypothermia
167
What is the average pulse rate of an adult?
60 to 90 beats per minute
168
What is the average pulse rate of an infant?
120 beats per minute
169
What is the average pulse rate of a child?
90 to 100 beats per minute
170
What are the 9 most common locations of a pulse?
1. apical (apex of heart)
2. radial (wrist at base of thumb)
3. carotid (front of neck)
4. femoral (femoral artery in groin)
5. popliteal (posterior surface of knee)
6. temporal (in front of ear)
7. dorsalis pedis (top of foot)
8. posterior tibial (inside of ankle)
9. brachial (inside groove above elbow)
171
What is the most common location used for taking the pulse?
The radial artery
172
Define tachycardia
abnormally rapid heart rate (over 100 bpm)
173
Define brachycardia
abnormally slow heart rate (blow 60 bpm)
174
What is the average respiration rate of an adult?
15 to 20 breaths per minute
175
What is the average respiration rate of an infant?
30 to 60 breaths per minute
176
Systolic measurement in the blood pressure measures what?
the amount of blood flow ejected from the left ventricle of the heart
177
Diastolic measurement in the blood pressure measures what?
the amount of resistance the blood meets due to systemic vascular resistance
178
Blood pressure is measured in what?
mm Hg (mm of mercury)
179
What is a pulse oximeter used for?
to measure the oxygen saturation in the patient
180
What is the oxygen saturation level for most patients?
95% or higher
181
What percentage of oxygen saturation indicates that the tissues are not receiving enough oxygen?
85% or lower
182
Three components of analog image receptor film/screen systems include what?
1. Cassette
2. Intensifying screen
3. Film
183
What four properties does an analog image possess?
density, contrast, detail, and distortion
184
Film speed is a measure of what?
the amount of density produced for a given amount of exposure
185
Carlton/Adler states that the second most effective method of reducing patient dose is what?
to use the highest possible film/screen combination
186
Extremity exams would warrant a high resolution/detail and would utilize a higher or lower film screen combination?
Lower (100-200 speed)
187
What are the two groups of digital detectors?
1. cassette-based (CR)
| 2. cassette-less (DR)
188
Speed class refers to what?
the operational exposure level at which a digital imaging system is operated
189
Contrast and dose have what type of relationship in digital imaging?
Contrast is unrelated to dose in digital imaging
190
What is exposure latitude?
the range of under or over exposure that can occur in producing an acceptable image and does not violate ALARA
191
Using a grid (vs non grid) dose what to patient dose?
increases it
192
Using a lower grid ratio while still maintaining the exposure (decreasing kVp or mAs) dose what to dose?
can significantly reduce it
193
It is recommended to use a grid if the body part is thicker than what?
10 cm
194
Source to skin distance must not be less than what for a stationary unit?
15 inches or 38 centimeters
195
Source to skin distance must not be less than what for a mobile unit?
12 inches or 30 centimeters
196
The fluoroscopic image receptor assembly serves as a primary protective barrier and must be what thickness of lead equivalent?
2mm
197
At the normal position for a radiologist or radiologic tech, the exposure rate is approximately what?
300mR/hr
198
By taking just two steps back, the exposure rate for a radiologist or radiologic tech can be reduced to approximately what?
5mR/hr
199
An audible signal must go off when a fluoroscopy unit timer reaches what time?
5 minutes
200
Federal standards have set limits of exposure rates of intensified fluoro units to what?
10R/min or 2.1R/min/mA
201
What is quality assurance?
it consists of activities that provide adequate confidence that a radiology service will render consistently high quality images and services
202
Quality assurance evaluating activities may include what?
```
interpretation of exams
maintenance of equipment
performance of procedures
filing systems
staff development
scheduling of exams
supply lines
```
203
What are the three steps in the quality assurance process?
identifying the problems or potential problem areas
monitoring the problem
resolving the problem
204
What is quality control?
the aspect of quality assurance that monitors technical equipment to maintain quality standards
205
Source-to-image receptor distance indicator must be accurate to within +/- what percentage of the indicated SID?
+/- 2%
206
Collimation error is allowed in +/- what percentage between the primary-beam image and the light field size?
+/- 2%
207
Positive-beam limitation (PBL) must be accurate to within +/- what percentage of the SID?
+/- 2%
208
Central ray alignment must be within +/- what percentage of the light field central ray?
1%
209
Congruency of the light and x-ray field may be tested by using what test?
the penny test
210
Define distortion
the misrepresentation of the size or shape of the structures being examined
211
What are the two types of distortion?
1. size
| 2. shape
212
What two factors affect size distortion?
OID and SID
213
What two main factors affect shape distortion?
Alignment (CR, part, IR) and Angulation (direction, degree)
214
Increasing the SID does what to size distortion?
decreases
215
Decreasing the SID does what to size distortion?
increases
216
Increasing the OID does what to size distortion?
Increases
217
Decreasing the OID does what to size distortion?
decreases
218
Increasing the patient thickness does what to size distortion?
increases
219
Decreasing the patient thickness does what to size distortion?
decreases
220
Improper CR alignment will do what to shape distortion?
increase it
221
improper anatomical alignment will do what to shape distortion?
increase it
222
Improper IR alignment will do what to shape distortion?
increase it
223
Improper direction of the CR angle will do what to shape distortion?
increase it
224
magnification size distortion is minimized by doing what?
increasing the SID
225
What is the formula for determining magnification?
M = SID/SOD
226
Foreshortening and magnification happen due to what?
changes in the anatomical part alignment (body part angled)
227
Elongation and magnification happen due to what?
changes in the IR and CR or IR and part alignment (IR angled)
228
Due to radiographs being considered legal documents, what 4 markings must be included on them?
1. patient's name and/or ID number
2. left or right markers
3. date of the exam
4. name of the institution or office
