Fluoroscopy Flashcards
(190 cards)
1
Q
What is fluoroscopy? What is its purpose?
A
When dynamic/moving images are displayed in real time.
To actively study the motion of organs and the movement of contrast media within anatomic structures in real time
2
Q
3 main components of a fluoroscope
A
- X-ray tube and generator
- Image Intensifier
- Video monitoring system
3
Q
mA range for fluoroscopy
A
0.5-5mA
4
Q
What generators are used for fluoroscopy?
A
High frequency (1%) or three phase (14%)
5
Q
Purpose of the image intensifier
A
Electronically brighten the fluoroscopic image by receiving the image-forming x-ray and converting it into a visible light image of high intensity
6
Q
Primary components of the tube type I.I
A
- glass envelope
- input phosphor
- photocathode
- electrostatic focusing lenses
- anode
- output phosphor
7
Q
What is the purpose of the glass envelope?
A
Allows the free flow of electrons from the photocathode to the anode
8
Q
What is the input phosphor made of and what does it do?
A
- glass or thin aluminum base
- cesium iodide (improved spatial resolution)
- absorbs x-rays and coverts their energy into visible light
9
Q
Purpose of the photocathode
A
- antimony and cesium compounds
- light photons release electrons from the photocathode through photoemission
- # of electrons directly proportional to intensity of light
10
Q
Purpose of electrostatic focusing lenses?
A
- focus electrons towards the output phosphor
- positively charged
11
Q
What is the output phosphor made of? What is its purpose?
A
- glass or aluminum with zinc sulphide (2.54cm)
- receives electrons from photocathode and emits 50-75x more light than what was received by the photocathode
12
Q
How can image brightness be changed by the image intensifier?
A
- minification gain
- flux gain
13
Q
Minification gain and its formula
A
-the image in condensed onto the smaller output phosphor from the larger input phosphor-it appears brighter because it is emitted from a smaller area
-minification gain = d(i)^2 / d(o)^2
(Diameter of input phosphor/diameter of output phosphor)^2
14
Q
What is flux gain and its formula?
A
- increased electron kinetic energy from the high voltage accelerating them releases more light from the output phosphor
- flux gain = # of output light photons / # of input x-ray photons
15
Q
What is brightness gain and its formula?
A
- how bright an image is with an I.I vs. without and I.I
- brightness gain = (minification gain)(flux gain)
16
Q
Does brightness gain increase or decrease with tube age? What can be done to compensate?
A
Decrease, must raise technique
17
Q
Describe the operation of and I.I
A
- x-rays pass through patient
- x-rays absorbed by input fluorescent screen
- a light image is produced (direct viewing possible)
- light photons strike photocathode
- photoelectrons are emitted by photocathode (photoemission)
- electrons are attracted to accelerating anode
- electrons focused onto output fluorescent screen
- electrons strike output fluorescent screen
- light photons emitted from output screen
18
Q
What happens when the electrons cross over at the focal point in the I.I?
A
The image in inverted
-Right becomes left
-Superior becomes inferior
Image is upside down and reversed
19
Q
Why do we use magnification mode?
A
- To enhance the image and increase the capability for a more accurate diagnosis
- moves the focal spot farther from the output phosphor
20
Q
Advantages/Disadvantages of magnification mode?
A
- Increased spatial resolution
- Increased contrast resolution
- Increase patient dose
21
Q
What is the purpose of an I.I coupling device? Two methods of coupling?
A
Connects the output phosphor to the image monitoring system
(CF= TV camera) (DF= CCD)
-Fiber optics
-Lens coupling
22
Q
What is fiber optic coupling? Advantages/disadvantages?
A
A bundle of tiny flexible glass or plastic fibers
- simplest method
- compact
- rugged (can be rough handled)
- inexpensive
- incompatible with auxiliary cameras
23
Q
What is lens coupling? Advantages/Disadvantages?
A
Uses a beam splitting mirror to redirect light from the output phosphor to aux devices and a monitoring system
- large
- must be moved gently (misalignment of mirrors causes blurring)
- enables simultaneous viewing of the image while it is being recorded
- enables connection to Cine and spot camera (aux devices)
24
Q
What is the imaging monitoring system? Two types?
A
Magnifies the image from the output phosphor of the I.I for easier viewing
- Direct: mirror optics
- Indirect: CCTV, TV cameras, CCDs in DF
25
How does direct viewing work?
Image from I.I is projected onto a mirror mounted on the side of the I.I tower.
- field of view is small
- low resolution
26
How does indirect viewing work?
- CCTV (closed-circuit television monitoring) most common
- a tv camera tube is connected to the output phosphor and then connected to a display monitor (tube converts visible light into electronic signal)
- brightness and contrast can be controlled electronically
- dynamic and static images can be recorded
27
What does a TV camera tube do? Types?
Converts visible light into electronic signals for television monitoring
- Orthicon
- Plumbicon
- Vidicon
- CCD (only in DF)
28
CF television monitors
convenience of viewing the image on a TV screen/monitor decreases the quality of the image
- decreases spatial resolution
- requires recording of the image on an alternate device to capture the high resolution from the I.I
29
Types of static recording systems?
- Cassette spot filming
| - Photospot camera
30
Cassette spot filming characteristics
- only capable with lens coupling
- located between patient and I.I
- uses fluoro x-ray tube to create image, not I.I
- slight pre-exposure delay to change to high mA setting
- has multiple modes to display numerous images on one film
- appears as radiograph
31
Characteristics of photospot camera
- only capable with lens coupling
- exposes one frame at a time (up to 12 frames/sec)
- receives image from the output phosphor of the I.I
- less patient dose compared to cassette spot film
- no exposure delay
- appears as live fluoro image
32
Dynamic recording systems
-Cinefluoroscopy
33
Characteristics of cinefluoroscopy
- only capable with les coupling
- similar to photospot (uses videotape to monitor and record images from I.I)
- no exposure delay
- high speed motion picture capture (up to 120frames/sec)
- ideal for cardiac, minimizes image motion, increased patient dose
34
What do all digital fluoroscopy systems have the capability to do?
Pulse fluoroscopy
35
2 methods of DF?
- I.I tube DF systems
| - Flat-panel DF systems
36
Components of DF
- Tube and generator: High frequency
- Image receptors: I.I or flat-panel
- Coupling devices: lens/fiber optic
- CCD
- ADC
- multiple viewing monitors (flat screen)
- operating console: for post-processing
37
What is the difference between CF I.I systems and DF I.I systems?
The I.I connects to a CCD (DF) instead of a vidicon (CF)
38
Flat-panel IR systems (FPIR) characteristics
- replace the I.I and vidicon components
- acts like an radiography IR
- smaller, lighter, easier to move
- unaffected by external magnetic fields
- pulsed mode capabilities where exposure time can be continuously varies, reducing dose to patient
39
What is interrogation time, extinction time, and duty cycle?
Interrogation time: time required for x-ray tube to be switched on and reach the selected kVp and mA
Extinction time: time required for the x-ray tube to be switched off
Duty cycle: period of time when the x-ray tube is energized
40
Advantages of Pulsed fluoroscopy
- decreased quantum mottle
- increased resolution
- increased SNR
- decrease probability of image flicker
41
How does OID affect things in pulsed fluoroscopy?
Decreased OID =
- increased resolution
- decreased dose
- decreased penumbra
42
DF coupling devices purpose and types
- fiber optic
- lens
Connects the I.I to the CCD
43
Purpose of the CCD and advantages.
Converts light to electrical charge
- small
- more sensitive to light (increased DQE)
- crystalline silicon (active component)
- increased contrast resolution
- linear response
- no lag, no warm up period
- ABC
- wide dynamic range
44
Advantages of CCD over vidicon
- increased contrast resolution
- increase spatial resolution
- increased SNR
- no maintenance or warm up
- unlimited lifetime and fast response time (high DQE)
- linear response, no lag time or blooming
- decreased patient dose
- no image distortion or lag
- enables use of an automatic brightness control
45
What is automatic brightness control?
Controls and maintains the brightness of an image by automatically adjusting the exposure factors to adapt to the thickness of the body part
46
Another name for ABC
Automatic brightness stabilization (ABS)
47
2 ways to control the image brightness with automatic brightness control?
- Monitor the current flow between the photocathode & anode: chamber is positioned in front of the output screen
- Monitor the intensity of light at the output phosphor: chamber is places after the output screen
48
ADC
Analog to digital converter
- located between CCD and array computer
- converts electrical signal from CCD to digital signal for computer
49
Why do we use an acquisition computer instead of a microprocessor?
- primary memory of an array processor is faster
- capable of processing thousands of functions at the same time
- applies algorithms to the incoming digital signal
50
DF television monitors compared to CF
- Higher SNR
- display incoming data in progressive mode (sharper image, less flicker)
- Flat panel high definition displays (LCD can replace CRTs)
51
What is the primary limitation of spatial resolution?
Monitors
52
What is image lag?
Persistence of luminescence of the screen after the x-ray stimulation has been terminated
Can occur with rapid movement causing blurred or ghost images on the monitor
53
Automatic gain control
- brightness of the image can be controlled by varying the sensitivity on the monitor
- exposure factors are not affected
- only video signal is adjusted
54
2 methods to control brightness of the displayed image
- ABS: adjusts exposure factors
| - AGC: adjusts video/digital signal, 1st choice better for patient
55
Benefits of DF
- Last image hold: last frame remains on monitor when x-ray beam is shut off
- Image grab/snapshot mode: frame can be saved on static monitor from the live monitor
- both result in reduced dose
56
Components of conventional Fluoro
- tube and generator
- image intensifier
- image distributor (lens coupling)
- aux cameras
- vidicon
- array computer
- console
- table side monitor
57
Components of convention/digital conversion fluoro
- tube and generator
- image intensifier
- image distributor (lens coupling)
- aux cameras
- vidicon
- ADC
- array computer
- console
- table side monitor
58
Components of digital fluoro with I.I and CCD
- tube and generator
- image intensifier
- fiber optics
- CCD
- ADC
- array computer
- console
- table side monitor
59
Components of Digital Flat panel fluoro
- Tube and generator
- direct/indirect detector with CCD
- ADC
- array computer
- console
- table side monitor
60
Digestive system examination
Esophagus: esophogram
Stomach and duodenum: upper gastrointestinal series, UGI, OS&D, barium meal/swallow, modified barium swallow
Small bowel: small bowel follow through, enteroclysis
Large Bowel: single or double contrast enema
61
How is the esophagus positioned in the body?
Anterior to the vertebra, posterior to the trachea and heart
| Passes through the diaphragm at T10
62
Esophagram contraindications and exam prep
Contraindications:
-sensitivity to contrast media used
-change of perforated bowel (mixture might escape into peritoneal cavity)
Exam Prep:
-no prep
-when imaging more than esophagus-nothing by mouth after midnight
63
What kind of contrast is used for an esophagram?
Thick barium: paste or thick powder mixture
64
Projections and positions of the esophagus? Centering for each
- AP or PA: 1" inferior to sternal angle (T5-T6 @MSP)
- Lateral: T5-T6 @MCP
- RAO or LPO (RAO preferred): T5-T6 10-15cm inferior to jugular notch, 5cm lateral to MSP on elevated side
- Optional swimmer's lateral (to see esophagus without superimposition)
65
Which position best demonstrates a barium filled esophagus between the shadows of the heart and vertebral column?
RAO 40 deg
66
What is the most anterior and posterior portion of the stomach?
Fundus
67
Air-Barium distribution in the stomach for each position
Supine: fundus and duodenal bulb barium filled, pylorus air filled
Prone: fundus and duodenal bulb air filled, pylorus barium filled
Erect: fundus is air filled, pylorus is barium filled
68
Stomach and duodenum contraindications and exam prep
- sensitivity to contrast media
- change of perforated bowel (could possibly use a water soluble contrast agent)
- NPO from midnight the night before
- no smoking or chewing gum (increase gastric secretions)
69
Other names for exam of esophagus, stomach, and duodenum?
- Upper GI
- UGI (series)
- OS&D
- Barium swallow
- Barium meal
70
Projections and positions for an upper GI
- RAO
- PA
- Rt Lateral
- LPO
- AP
71
What kind of contrast is used for an upper GI exam?
Usually 2 kinds (positive and negative)
72
How do we coat the walls of the stomach with contrast?
Patient does a 360 deg log roll
73
Upper GI centering for each body habitus
Sthenic: CR at L1 above L3 and midway between spine and upside lateral border of abdomen
Asthenic: CR 5cm below the level of L1
Hypersthenic: CR 5cm above L1 and nearer midline
74
Which is the best image of the pyloric canal and duodenal bulb in profile?
RAO
75
Obliques for body habitus and positions of upper GI
```
RAO:
Sthenic: 45-55 deg
Asthenic: 40 deg
Hypersthenic: 70deg
LPO:
Sthenic:45 deg
Asthenic: 30deg
Hypersthenic: 60deg
```
76
Why do we do a modified barium swallow?
- Performed to assess the patient's ability to swallow
- Patient observed while swallowing foods of various consistencies from thick fluids to thick paste barium
- Patient history usually queries aspiration
77
What is veiling glare?
Loss of contrast due to light, x-ray, or electron scattering within a lens system
78
What is pulse fluoroscopy?
- machine pulses on and off
- decreased patient dose
- exposure time can be manipulated and varied instead of continuous
79
How does a vidicon work?
The target of a television camera tube conducts electrons only when illuminated
Coverts light to electrical signal that is sent to the television monitor where it is reconstructed as an image
80
Contraindications and bowel prep of a small bowel study?
- sensitivity to contrast media used
- chance of perforated bowel
- bowel obstructions
- NPO from midnight the night before
- no smoking or chewing gum
81
What must each film have when taking radiographs during a small bowel follow through?
A time marker
82
What is the "money shot" of a small bowel follow through? How does the radiologist get it?
Image of the terminal ileum going into the cecum
| By using a compression paddle to move away surrounding bowel
83
How long after is the initial image take for a small bowel follow through?
Usually 15 mins after the patient drinks the first cup of barium
84
Will there be air in the stomach during a small bowel follow through?
No
85
Where do you center for a small bowel follow through for the initial image? For other images?
Initial image: 10cm above crests (L4) to include stomach, PA is better
Remainder of images: CR at the level of the crests and MSP, taken every 30 mins
86
Which is better for small bowel follow through images...AP or PA? Why?
PA
- less OID
- less gonadal dose
- compression on front separates bowel loops
87
Average emptying time of a normal stomach? When will the barium reach the ileocecal valve?
Stomach: 2-3 hours
| Ileocecal valve: 4-5 hours
88
If transit time is too long, what can we do?
- give patient something to eat: promote peristalsis
- give patient cold water: flushes it through
- have patient lie on their right side: gravity does its job
89
What is an enteroclysis? What is injected? When would this be done?
- injection of nutrient of medical liquid into the bowel by an NG tube at the duodenojejunal juntion
- barium followed by methylcellulose (adhered to and distends bowel, can see mucosa well)
- if patient has inflammatory bowel or Crohn's: can see better than if barium was swallowed
90
Disadvantages of enteroclysis compared to SBFT? Indications to perform an enterocysis?
- increased patient discomfort
- possibility of perforation
- potential of high radiation dose
- clinical history of small bowel obstructions or Crohn's
- evaluation of small bowel tumors
91
Upper GI pathologies
- Esophageal Achalasia
- Esophageal Varicies
- Esophageal Atresia
- Esophageal Cancer
- Peptic Ulcer
- Hiatal Hernia
- Gastric Cancer
- Crohn's Disease
- Small Bowel Obstruction
92
Radiographer's responsibilities for an esophageal, upper GI, or small bowel follow through study?
1. Prepare fluoro room
2. Prepare contrast media
3. Introduce yourself and obtain clinical history. Confirm DLMP for female patients
4. Confirm patient has prepared for exam (NPO 8hrs prior, no smoking or chewing gum)
5. Explain procedure
6. Introduce the patient to the radiologist and assist the radiologist
7. Assist the patient during the procedure
93
Routine esophagus
RAO 35-40 deg
Lateral
AP (PA)
94
Routine stomach
```
RAO
PA
Right lateral
LPO
AP
```
95
What are the 3 ways barium can be administered for a small bowel exam?
1. Orally
2. Reflux filling via large volume barium enema
3. Direct injection via a tube placed in the small bowel (enteroclysis)
96
Why do we center higher on the initial image on a small bowel series?
To get the stomach
97
Indications for a barium enema?
- Colitis
- Ulcerative colitis
- Diverticulosis/Diverticulitis
- Intussusception
- Neoplasms
- Volvulus
98
Bowel prep and contraindications for a barium enema?
- possible perforation
- possible obstruction
- 2day diet of clear liquids
- laxatives or a cleansing enema
- NPO from midnight the day before
99
Is a barium enema single or double contrast?
Can be single or double
100
What is an important question to ask when interviewing a patient for a barium enema?
Diabetic?
101
Types of enema tips?
- Plastic disposable (no balloon)
- Plastic disposable with retention (balloon)
- Plastic disposable air-contrast retention (balloon)
102
Tip insertion steps for a barium enema
- be sure there is little to no air in enema tube
- place patient in Sim's position on left side with knees bent
- inform patient the tip will be cold and wet from lubrication (breathing instructions)
- re-enforce tip security through instructions, tape, and additional equipment
- total insertion should not exceed 4 inches
103
What 2 medications are used to relax peristaltic action of the bowel? How are they administered?
Glucagon or Buscopan
| IV or IM
104
Single contrast routine projections/views for a barium enema?
- AP or PA
- LPO
- RPO
- Sigmoid/axial
- Lateral rectum
- Post Evac
105
Double contrast projections/views for barium enema?
- AP or PA
- R and L Lateral decubitus
- Obliques
- Sigmoid/axial
- Lateral rectum
- Post Evac
106
What do the RAO/LPO obliques for barium enema demonstrate?
Best demonstrate the hepatic (right colic) flexure
107
What do the LAO/RPO obliques for barium enema demonstrate?
Best demonstrate splenic (left colic) flexure
108
Where do you center for barium enema obliques? How much rotation?
Center at L4
2.5cm lateral to up side of MSP (for posterior obliques)
2.5cm left or right of MSP depending which oblique (anterior obliques)
Patient rotated 35-45 degree
109
Where do we center for left and right lateral decubitus for barium enemas? What part of the large bowel do they deomstrate?
Center at the level of the crests
LLD: ascending colon
RLD: descending colon
110
Where do we center for AP or PA views of the large bowel? What structured are demonstrated?
- center at the crests
- PA: transverse is barium filled
- AP: transverse in air filled
111
Where do we center for a lateral rectum?
-center at the ASIS and MCP
112
Where do we center for a PA or AP axial sigmoid? How do we angle our tube for each?
- PA: 30-40 deg caudad, CR to exit at ASIS
| - AP: 30-40deg cephalad, 5cm below ASIS
113
Where do we center for a post evac for the large bowel?
-CR at the level of the crests
114
3 types of contrast?
- Barium: positive, comes in powder, liquid, or gas
- Air or Gas: negative, pill or granule form, carbon dioxide or nitrogen also used
- Water soluble: positive, liquid, used when there is a suspected perforation or patient is going for surgery
115
Common "name brand" water soluble agents used for exams include:
- Gastrografin
- Hypaque
- Telebrix
- Conray
116
Average emptying time of the stomach? How long for substance to reach rectum?
2-3hrs to empty stomach
| 24hrs to get to rectum
117
Indications to perform a single or a double contrast enema exam?
- Patient mobility
- Patient ability
- Patient history and pathology
- Unable to tolerate prep
118
Routes of contrast administration for the biliary system?
- Intravenously
- Direct injection
- Indwelling
119
Exams for the biliary system?
- Endoscopic Retrograde Cholangiopancreatography
- Percutaneous Retrograde Cholangiography
- Intraoperative Cholangiography
120
What is an ERCP?
- gastroenterologist puts endoscope down throat to duodenum
- located ampula of vater and inserts a cannula
- injects contrast into the common bile duct
- "clean procedure" not sterile
121
Indications/contraindications of an ERCP
Indications:
-performed when clinical and radiologic findings indicate abnormalities
Contraindications:
-acute infections of biliary system (pancreatitis)
-pseudocyst of pancreas
-elevated creatinine or BUN levels
-possible sensitivity to contrast
122
ERCP: How is the patient laying when the endoscope is inserted? What position is the patient moved to once the cannula is inserted?
- LAO
| - Sim's position
123
ERCP: dense contrast may obscure ________. To fix this problem you should _________?
- small stones
| - dilute contrast
124
Therapeutic ERCPs include the following procedures:
1. Stent placement
2. Stone removal
3. Expand stenosis/narrowing of ducts: a cut can be made to open distal end of a duct
125
Indications for a PTC?
- jaundice
- dilated ducts
- unclear as to why there is an obstruction
- if ERCP contraindicated
126
What is a PTC?
- Contrast injected by radiologist through a chiba needle into biliary ducts
- tech monitors vital signs and patient care
- AP spot films taken after ducts filled with contrast
127
What is a therapeutic PTC? When is it performed?
Performed if dilated ducts are identified by a diagnostic PTC
- a drainage catheter is placed for drainage of excess bile from biliary ducts
- or stone extraction
128
Risks and complications of a PTC?
- Pneumothorax:
- Liver hemorrhage: hemorrhage internally or bile may escape
- Peritonitis: bile may escape into peritoneal cavity leading to inflammation
129
Risks of an ERCP?
-perforation
130
What is an Operative Cholangiogram? Who is it performed by?
- Performed in the OR by the surgeon
- Investigates patency of biliary ducts, functionality of sphincter and ampulla, presence of stones, and dilatations of the ducts
- Water soluble contrast injected directly into CBD
- T-tube (post-operative) (can inject contrast and remove stones through here)
131
What images do we take for an operative cholangiogram?
-AP
-RAO (15-20 deg)
Trendelenburg may be required to fill intrahepatic ducts
132
Prefixes for the genitourinary system: URO, CYSTO, NEPHRO, CYSTOURETHRO, PYELOGRAPHY, URETHRO
```
URO: entire urinary tract
CYSTO: bladder
NEPHRO: kidney
CYSTOURETHRO: bladder and urethra
PYELOGRAPHY: renal pelvis and calyces
URETHRO: urethra
```
133
How do the kidneys sit in the body?How do the kidneys lie in relation to the detector in posterior obliques?
Rotated 30 degrees anteriorly towards the aorta
The lower kidney is perpendicular to the IR
The elevated kidney is parallel to the IR
134
How do the ureters sit in the body?
Each ureter initially curves forward and then curves backward on entering the pelvis/bladder
135
How much do the kidneys move between inspiration and expiration? When are they lower? At which vertebral level do they sit at?
Move between 1-4cm, lower on inspiration
Right kidney is normally lower because of liver
T12-L3
136
Urinary system exams
- KUB
- IVU
- Retrograde Urography
- Cystography
- Voiding Cystourethography
- Percutaneous Catheter Nephrostomy
137
Indications for urinary studies?
- renal caluli are most common
- chronic urinary tract infections
- urethral strictures
- anatomic evaluation of renal pelvis, calyces, and ureters
138
Exam prep for urinary studies?
- cleansing of bowel to avoid gas or fecal shadows that could obscure structures of interest
- NPO 8hrs before exam
139
Purpose of a KUB?
- verify patient prep
- determine acceptable exposure factors
- verify position of structures
- detect any abnormalities prior to contrast given (renal calculi or lesions)
140
KUB positioning
- supine
- 35x43
- CR at iliac crests
- Collimate to ASIS
- include kidneys to symph
- Expose on expiration to move diaphragm
141
Purpose of an IVU
- visualize the collecting portion of the urinary system
- assess functional ability of the kidneys
- evaluate the urinary system for pathology or anatomic anomalies
142
Indications and contraindications of a IVU?
Indications:
-abdominal masses, renal tumours/cysts, urolithiasis, pyelonephritis, hydronephrosis, trauma, pre-op evaluation
Contraindications:
-renal failure, diabetes with renal insufficiency, renal hypertension, congestive heart failure, prior contrast reaction
143
Lab tests for kidney function
- GFR
- Creatinine
- BUN
144
Which drug needs to be withheld for 48hrs after an exam requiring contrast?
Glucophage (metformin)
145
Before injection of contrast we....
- collect history and explain how long study will take (clinical history, LMP, allergies, blood chemistry)
- have patient fill out contrast consent form
- have patient void prior to exam
- draw up contrast
146
General IVU procedure
- scout KUB taken and shown to radiologist
- clamp any urinary catheters
- inject contrast
- note time injection started
- observe patient for any signs of reactions
147
Basic imaging routine for an IVU
* *time markers must be used on each image
1. 30 sec or 1 min AP (just kidneys-nephrogram)
2. 5 min AP (just kidney or full KUB)
3. 10 min AP (full length, entire system)
4. 20 min obliques (30 deg)
5. Post void (PA or erect AP)
148
AP kidney positioning and centering
- include time marker
- CR midway between xiphoid and crests
- angle of ribs at L1
- bottom of IR at iliac crests: 24x30
- usually 30 sec and 5 mins taken
149
Posterior oblique positioning for an IVU
- rotate patient 30 deg
- CR at crests, 10cm lateral towards upside
- Full length
- expose on expiration
150
Why would we apply compression to the distal ureters at level of ASIS? Contraindications of this?
Allows for enhanced visualization of renal pelvis and calyceal filling of proximal ureters
-stones, recent surgery, pelvis mass/tumour, aneurysms, or trauma
151
Purpose of retrograde urography? Where is it performed?
- non-functional exam
- determine location of undetected calculi or other obstruction
- view renal pelvis and calyces for signs of infection or structural defect
- performed in the OR with SURGICAL ASEPSIS
152
Procedure of retrograde urography?
- using a ureterocystoscope, the urologist finds opening to ureter and injects water soluble contrast directly into kidneys
- preliminary film performed before contrast
- images done AP using x-ray or fluoroscopy
- ensure markers are on, no set time interval for images
- can also do stent insertion/removal or stone removal
153
Previous name for retrograde urography?
Retrograde pyelogram
154
Indications for bladder examinations?
- vesicoureteral reflux
- recurrent UTIs
- neurogenic bladder
- bladder trauma
- fistulae
- urethral stricture and posterior urethral valves
155
Retrograde cystography
- performed to rule out tumours, calculi, trauma, and inflammatory disease of the bladder
- non-functional exam
- performed in x-ray department by radiologist
- contrast administered by urinary catheter (gravity only)
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Cystogram projections
1. AP axial bladder: 10-15 deg caudad, distal ureters, proximal urethra, and entire bladder
2. Posterior oblique: 40-60 deg rotation, 5cm superior to symph, 5cm medial to elevated ASIS, UV junction of upside
3. PA axial bladder: not common, 10-15 cephalad, MSP
4. Lateral: anterior and posterior walls of bladder, trigone, 5cm superior and posterior to symph at MCP
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Retrograde Cystography vs. Voiding Cystrography: why we perform these exams?
RC: performed to evaluate size, shape, and location of bladder and abnormalities
VC: performed to evaluate patient's ability to urinate or void, functional exam
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What is the radiologist looking for while the patient is voiding?
Reflux
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What is Percutaneous Catheter Nephrostomy Tube Insertion? Purpose?
Invasive, therapeutic procedure, establishes an opening between the renal pelvis and the patient's skin
- SURGICAL ASEPSIS
- done in interventional suite
- temporary
- drainage, drug administration, or instrument insertion (to removed stone, biopsy brush, balloon catheter)
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PCN procedure
- kidney localized with U/S
- long, fine bore needle is inserted into kidney
- guide wire is inserted through needle into calyces
- needle is removed and dilators are used to expand opening
- catheter is threaded over guide wire into position
- catheter is secured to surface of skin with sutured and a drainage bag is attached
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Complications of a PCN?
- infection
- catheter dislodgement
- catheter obstruction
- hemorrhage (kidneys are vascular)
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Follow up procedure of a PCN?
- drainage bad is removed
- syringe of contrast is connected to catheter with extension
- radiologist will take images of the area of concern
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Methods of stone removal?
- Extracorporeal Shock Wave Lithotripsy: shock waves from electrical source pulverize calculi (>2mm), pass down ureter
- Laser Stone Fragmentation: guidewire inserted into ureter to kidney, scope inserted, stone is disintegrated with laser, fragments extracted or flushed out
- Percutaneous Nephrolithotomy: incisions into kidney for removal of calculi, basket extraction or ultrasonic lithotripter
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Where is Laser stone fragmentation performed?
In the urology suite under general anesthetic
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What is a hysterosalpingography?
- contrast injected into uterus and fallopian tubes
- indicated by infertility
- size, shape, position, patency of uterus and tubes
- lesions, masses, and fistulas
- MUST NOT BE PREGNANT
- performed by genycologist in radiology department
- lithotomy position
- we will NOT see ovaries
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What is fluoroscopy?
Real-time dynamic viewing of anatomical features using x-ray
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Exams performed using fluoro?
- barium studies
- barium enema
- small bowel follow through
- stomach and duodenum
- esophageal studies
- arthrograms
- angiography
- biliary system exams
- genitourinary system
- OR cases
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What is cinefluorography?
"Movie-style" imaging that uses film or digital frame imaging
- used in cardiology or neuroradiology
- produces highest patient dose
- uses higher x-ray tube voltage and current
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3 rules of radiation protection?
1. Time
2. Distance
3. Shielding
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True or false? Fluoro procedures produce the greatest patient radiation exposure rate in digital radiography?
True
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Regarding II and tube positioning, how do we reduce patient dose?
- keep x-ray tube as far away as possible
| - keep I.I as close as possible
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Purpose of the I.I? Benefits?
- used to increase brightness on the screen = can lower mA
- increased brightness
- radiologist no longer needs to adapt to the dark
- improves visual activity
- reduces technical factors
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What problem occurs with magnification mode?
Vignetting
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True or false? In magnification mode we get increased spatial and contrast resolution?
True
175
Benefits of pulsed fluoroscopy?
- decreases dose to patient and to tech
- less exposure time
- helps extend the life of the tube
176
Air kerma exposure limitations?
With ABC: 100mGy/min
| Without ABC: 50mGy/min
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Usual kVp used for adults?
75-110 kVp
178
________ is a mandatory function that all fluoro units must have?
Cumulative timing device: records total amount of tube on time
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Maximum ESE?
100mGy/min or 10R/min
180
Intensity at the table top should not exceed?
21mGy/min or 2.1R/min
181
Units with high level control may have a skin exposure rate of?
200mGy/min or 20R/min
182
What is the dose area product?
Reflects the dose and the area of radiation
183
What happens to DAP as the field size increases?
It increases even if the dose remains unchanged because more tissue exposed = higher DAP
184
What are diagnostic reference levels?
not limits, but guidelines
- related to the clinical purpose of the exam
- 20-70Gy/cm for an abdomen
- 30-60Gy/cm for a barium enema
- 35-75Gy/cm for a coronary angiography
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What is high level control fluoro used for?
-drainage
-biopsy
-angiography
To allow visualization of small, low contrast anatomy
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Protective barriers?
- detector slot cover: 0.25mm Pb
- protective curtain: 0.25mm Pb
- I.I housing: 2mm Pb equivalent
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Occupational dose comes from?
- long exposure times
- failure to use protective curtain
- extensive use of cine as a recording medium
188
We can reduce occupational dose by?
- have a rotating tech schedule
- using lead aprons, thyroid shield, glasses, gloves
- utilizing movable shields
- using bucky slot shielding devices
- stand behind the control booth when possible
- keep hands out of beam
- be aware of body position with respect to beam
189
How to minimize the dose to patients?
- use proper technical factors
- maximize SID
- minimize OID
- limit the use of mag
- control fluoro time
- use last image hold
- reduce field size
- minimize field overlap
- use pulse fluoro when possible
- use low frame rates
- document dose
190
Quality control tests?
1. Exposure linearity: tests for constant output for various mA and exposure times (within 10%)
2. Exposure Reproducibility: tests sequential exposures (+/-5%)
3. Protective Apparel Testing: check for cracks, tears, or holes
