Fluoro Final Exam Review Flashcards
3 ways to inject contrast media?
- Indwelling
- Direct
- Intravenously
Which exam requires direct puncture of the biliary ducts?
Percutaneous transhepatic cholangiogram
Functions of the gallbladder?
- store bile
- concentrate bile
- secrete bile
Purpose of an operative cholangiogram?
- investigate patency of biliary ducts
- functionality of sphincter
- presence of stones, stricture, or dilatations
Advantages of laparoscopic surgery over operative cholecystectomy?
- less pain
- faster recovery
- less time in hospital
- smaller incisions
- cost savings
Biliary system exams?
- Endoscopic retrograde cholangiopancreatography
- Percutaneous Trashepatic Cholangiogram
- Operative cholangiography
- Post-operative cholangiography
Purpose of a diagnostic ERCP?
- demonstrate strictures, dilatations, or small lesions within the biliary or pancreatic ducts
- check patency of biliary and pancreatic ducts
- visualize stones or narrow duct
Purpose of a therapeutic ERCP?
- removal of small lesions
- removal of stones
- dilate a blocked or narrowed duct
Contraindications of an ERCP?
- pseudocyst of pancreas
- acute infections of the biliary system (pancreatitis)
- hypersensitivity to contrast
- elevated creatinine or BUN
Dense contrast may obscure ________. What can we do to fix this?
Small stones. Dilute the contrast
Prep for an ERCP?
NPO for at least 1hr prior to prevent aspiration
NPO for 10 hrs post to prevent irritation
Who is a PTC performed by?
Radiologist, tech, and nurse
Indications for a PTC?
- jaundice
- dilated ducts
- unclear as to why there is an obstruction
Possible complications of a PTC?
- pneumothorax
- liver hemorrhage
- peritonitis
Purpose of a PTC
To demonstrate the biliary ducts
What images are taken for a PTC?
AP spot films
What kind of needle is used for a diagnostic PTC?
Chiba
Purpose of a therapeutic PTC?
To remove stones
Purpose of an operative cholangiogram?
- patency of ducts
- functionality of sphincter
- presence of stones
- presence of strictures or dilatations
Exposures taken for an operative cholangiogram?
- AP
- RPO: 15-20 deg
Where is an operative cholangiogram performed?
In the OR by the surgeon, surgical asepsis
Where is a post-operative cholangiogram performed?
In the radiology department
What may be required to fill the intrahepatic ducts with contrast?
Trendelenberg
What exam can be done if patient is contraindicated for an ERCP?
PTC
Which part of the kidney is more posterior?
Superior
How much do the kidneys move between inspiration and expiration?
1-4cm
How much do the kidneys move from supine to upright?
5cm
At what vertebral levels do the kidneys lie?
T12-L3
Urinary system exams?
- KUB
- IVU
- Retrograde urography
- Cystography
- VCUG
- PCN
Indications for a urinary study?
- renal calculi
- chronic urinary tract infections
- urethral strictures
- anatomic evaluation of the renal pelvis, calyces, and ureters
Locations of ureter contrictions?
- Vesicoureteral junction
- Ureteropelvic junctions
- Brim of pelvis
What modality is becoming more common to discover kidney stones? Why?
CT
- safe, less invasive, no contrast used
- accurate
- disadvantage is high dose and not always available
Prep for urinary studies?
- NPO 8hrs prior
- bowel cleansing required to avoid gas and fecal shadows
Purpose of the KUB?
- verify patient prep was successful
- determine exposure factors
- verify position of structures
- detect any abnormalities
Positioning for KUB?
- supine
- CR at crests (L4)
- collimate to ASIS
- include kidneys to symph
- expose on expiration
- male shielding below superior margin of symph
Purpose of an IVU?
- visualize collecting portion of the urinary system
- assess functional ability of the kidneys
- evaluate the urinary system for pathologies or anatomic anomalies
Indications for an IVU?
- abdominal masses
- renal tumour/cysts
- urolithiasis
- pyelonephritis
- hydronephrosis
- trauma
- pre-op evaluation
Contraindications for IVU?
- renal failure
- renal insufficiency
- renal hypertension
- CHF
- prior contrast reaction
- anuria
- sickle cell anemia
- multiple myeloma
- Pheochromocytoma
What medication must be stopped for 48hrs post-contrast?
Glucophage
Routine projections for an IVU?
- 30sec to 1 min AP (nephrogram, kidneys only)
- 5 min AP kidney
- 10 min AP (full)
- 20 min obliques (full)
- Post void
AP kidney positioning
- CR midway between xiphoid and crests (L1)
- bottom of IR at crests (24x30)
- include time marker
Oblique positioning for IVU?
- posterior obliques
- 30 deg rotation on patient
- CR at level of crests, 10 cm lateral to elevated side
- expiration
- time marker
Why do we use compression?
Allows for visualization of the renal pelvis and calyceal filling and proximal ureters
Contraindications of compression?
- stones
- recent surgery
- pelvis mass/tumor
- aneurysms
- trauma
Purpose of retrograde urography?
- to determine location of undetected stones or other obstruction
- to view renal pelvis and calyces for signs of infection or structural defect
Where is retrograde urography performed?
In the OR by a surgeon, surgical asepsis
Images for retrograde urography?
AP, no set time interval, urologist instructions
Indications for bladder exams?
- vesicoureteral reflux
- recurrent UTI
- neurogenic bladder
- bladder trauma
- fistulas
- urethral stricture and posterior urethral valves
Purpose of retrograde cystography?
-rule out tumours, stones, trauma, and inflammatory diseases of the bladder
Where is retrograde cystography performed?
In the x-ray department by a radiologist
What happens if you try to introduce contrast under pressure to the bladder?
It could rupture
Cystogram projections?
- AP axial bladder
- Posterior obliques
- PA axial bladder
- Lateral
AP Axial bladder positioning?
- supine
- 10-15 deg caudad
- CR 5 cm above symph
- expiration
- urinary bladder not superimposed by bones
- distal ureters and proximal portion of urethra demonstrated
PA Axial Bladder
- prone
- 10-15 deg cephalad
- CR 2.5cm distal to tip of coccyx
- expiration
Posterior oblique bladder positioning?
- 40-60 deg patient rotation
- CR 5cm above symph and 5cm medial to elevated ASIS
- expiration
- distal ureters (UV junction on upside), bladder, and proximal portion of urethra demonstrated
Lateral bladder positioning?
- true lateral
- CR 5cm above symph and 5cm posterior to symph
- expiration
- anterior, posterior, and base of bladder
Purpose of a VCUG?
Evaluate patients ability to void
Difference in positioning for a male vs. a female for a VCUG?
Female: AP or slight oblique
Male: 30 deg RPO
Purpose of a Percutaneous catheter nephrostomy?
- drainage
- drug instillation
- instrument insertion
Complications of a PCN?
- infection
- catheter obstruction
- catheter dislodgment
- hemorrhage
What is the follow up of a PCN called?
Nephrostography
Methods of stone removal?
- extracorporeal shock wave lithotripsy
- laser stone fragmentation
- percutaneous nephrolithotomy
Extracorporeal shock wave lothotripsy
- non invasive
- stones must be less than 2mm in size
- uses shock waves from an electrical source to pulverize stone
- ureter must not be obstructed
What are taken before a ESWL?
- prelim abdomen film
- IVU
Where is Laser stone fragmentation performed? What does it entail?
In the urology suite under general anesthetic
-scope in inserted into ureter and laser is blasted at stone
What is percutaneous nephrolithotomy?
- incision made into kidney to remove the stone
- basket extraction to remove small stones
- ultrasonic lithotripter to break up large stones
Purpose of a hysterosalpingogram?
Size, shape, and position of uterus and tubes
Most common indication of a hysterosalpingogram?
Infertility
What is fluoroscopy?
Real-time dynamic viewing of anatomical functions using x-ray
What effect does increasing kVp have on dose?
- decrease dose if mA remains the same because less if absorbed
- increase dose because we have less penetrability and will need to compensate by increasing mA
List come procedures that would utilize fluoroscopy?
- BE
- SBFT
- Esophageal studies
- Arthrograms
- Angiography
- Biliary system exams
- Genitourinary system exams
- OR cases
- Pacemaker insertions
- Hip pinnings
Normal range of kVp used to perform fluoro exams on adults?
75-110 kVp
How does SID affect dose
-increased SID = decreased dose
How does OID affect dose?
-increased OID = increased dose because decreased distance to source
What are quantity and quality?
Quantity: amount of x-ray photons, mA
Quality: strength of x-rays, kVp
How does focal spot affect dose?
It doesn’t
What is the most effective mechanical methods of decreasing patient dose?
Collimation
How does filtration effect dose?
-increased filtration = decreased dose because it absorbs low energy photons
Why can’t we achieve the ideal combo of technical factors?
We have to maintain a balance between dose and image quality
How do grids affect dose?
Grid = increased dose because we have to raise out mA
What are stochastic effects?
“Probabilistic”
- no threshold
- increased chance with increased dose
What are non-stochastic effects?
“Deterministic”
- have a threshold
- increased severity with increased dose
What is a somatic effect?
The effects only take place in the person irradiated
4 main components of the I.I
- Input phosphor: converts radiation to light
- Photocathode: converts light to electrons
- Electrostatic Focusing lenses: direct electrons towards anode
- Anode: attracts electrons emitted from photocathode
- Output phosphor: receives electrons, emits light
- Glass envelope: maintains vacuum
How does mag mode affect dose?
Increased it because the image appears dimmer due to decreased photoelectrons on the output phosphor so we need to increase out mA to compensate
When the I.I is closest to the patient, the dose _______?
Decreases
What are the advantage of digital fluoro over conventional that can be used to decrease dose?
- pulsed fluroscopy
- last image hold
- pulsed progressive fluoro
When is cinefluorography used? Why is it bad?
- cardiology
- neuroradiology
- uses a higher tube voltage and current
Purpose of the I.I?
Increase the brightness on the screen
Benefits of an I.I?
- increased brightness
- rads don’t need to adjust to dark
- improves visual acuity
- reduces technical factors
Advantages of mag mode
- increased spatial resolution
- increased contrast resolution
How does pulsed fluoro work?
When the beam is off the output screen in scanned and the image appears on the monitor, radiation is pulsed back on for the next image
As value increases the I.I flux gain _______?
Decreases
Air kerma exposure rate limitation?
- With ABC: 50mGy/min
- Without ABC: 100mGy/min
Purpose of filtration
To reduce skin dose
Minimum filtration?
2.5mm Al
With I.I, 3.0mm or higher
What is a mandatory function that all units must have as stated in the SC35?
Chronometer
Max entrance skin exposure rate?
-100mGy/min
Intensity at tabletop should not exceed?
-21mGy/min
Units with high level control may have a skin exposure rate of?
-200mGy/min
What is DAP
Dose area product: reflect the dose and area of radiation
DAP increases as field size _______
Increases
What are DRLs used for?
To promote better control of patient exposure, used as a guideline not a limit
DRLs
Abdomen: 20-70Gy/cm
BE: 30-60Gy/cm
Coronary Angriography: 35-75Gy/cm
What is high level fluoro used for?
Interventional procedures: drainage, biopsy, angiography
High level fluoro dose is controlled by?
Frame speed. Lower frame speed = lower dose
To best monitor effects in dose we must be diligent in?
- patient monitoring
- radiation dosimetry
- accurate record keeping of dose levels
Protective barriers?
- Detectors slot cover: 0.25mm Pb
- Protective curtain: 0.25mm Pb
- I.I housing: 2mm of Pb
Occupational dose comes from?
- long exposure times
- failure to use protective curtain
- extensive use of cine as a recording medium
We can reduce tech dose by?
- rotating tech sched
- use lead aprons
- use mobile shields
- use bucky slot shielding devices
- keep hands out of beam
- be aware of body position with respect to beam
- stand behind control booth when possible
Q/C
- Exposure linearity: constant output for various mAs combos, within 10%
- Exposure reproducibility: sequential exposures, within 10%
- Protective apparel testing: cracks, tears, or holes
