Final Flashcards
Xrays
- Electromagnetic radiation
- Electrons interact
- Invisible
- Can’t be felt
- Ionizes atoms
- Penetrates matter
Has particles and waves
xray beams are - charge
Absorbtion
- Atomic number
- Density of object
- energy of xray
Cathode (filament): -
- Coiled tungsten
- High Melting point
- High Atomic #
- mA heats filament
Anode (target): +
- Tungsten with copper base
- Stationary (dental) or Rotating
1% are xrays, 99% are heat
Wilhelm Conrad Roentgen - father of xrays
Xray Damages
Ionization vs Excitation
Somatic vs Genetic
Ionization: Displaces electrons
Excitation: strikes electrons to higher orbit
Somatic: Damage over a person’s lifetime.
- Cancer
- Catarats
- Anemia
Genetic: Damage to DNA/Choromosomes
- Birth defects
Xray Safety
Dosimetry
maintain Distance
wear 0.5mm lead apron/gloves
Collimate
Use good technique chart and technique
Use 2.5 mm aluminum filters
Xray labels
Patient name
Vet hospital
Dr name
Date of radiograph
Patient ID (age, sex, breed)
Technique Chart
Extremity/Skull
Thoracic
Abdomen
Pelvis/Spine
Avian/Exotic
Xray Density vs Contrast
Density: Degree of darkness (mAs)
- high Penetrating power
- longer develepment time
- longer development temp
- increase in mAs
- Increase KVP
- High # of xrays reaching film
Contrast: brightness b/t 2 areas (kVp)
- High Contrast = Short Scale (bones)
- Low Contrast = Long Scale (lots of grays - abdomen)
Increase mAs 50%
- cast
- obses
Decrease mAs 50%
- neonates
Photons
Bundles of energy
Has no electrical charge
Has no mass
wavelength vs frequency
Wavelength: Distance
Frequency: Cycle per second
Short wavelength = More Energy = Travels further
High frequencey = More penetration = Travels deeper
Elecrtromagnetic Spectrum
Radiowaves
Microwaves
Infradwaves
Visible light
UV
Xrays
Gamma rays
Heel Effect
Focal Spot
SID
Grid
Backscatter
Heel Effect: Decrease in xray intensity on anode side due to an anode target angle
- Place thickest body part under cathode side
Focal Spot - where the electrons hit the target
- small spot = sharper image
- too small = overheats
SID - Distance b/t focal spot and film. 40
- Short distance = decrease sharpness
Grid - Prevents scatter radiation. Placed b/t patient and film
Backscatter - Radiation scatter reflected from behind image plane to image
Xray Distortions
Geometric Distortion
- object is not parallel to film
Foreshortening
- 2 objects are not parallel to each other
Magnification
- Object is further from film
- Looks fuzzier
Elongation
- Object is not directly under radiation source
Films
- Silver halide film -> metallic silver (exposed)
- Or Silver bromide
- has fluroescent plastic
- has phosphor crystals
- 95% light is emitted from screen
- 5% directly from xrays
- Discard after 7 years or artifactual
Unexposed film & Processed: Clear
Exposed & Processed: Black
Exposed & Unprocessed: Purple
Film Processing
Development
- 5-7 min. half the time of fixer
- 68-72 temp
- Converts silver halide into black metallic silver
- Replace developer when green
Rinse (Stop bath)
- 30 sec.
- acetic acid
- 68-72 temp
- stops developing process
- Clears contaminants
Fix
- 10 mins. Double the time of developer
- clears unexposed crystals
- film is viewable after 1 min
- Replace if clearingtime >2-3 min or over/under exposed
Wash bath
- 20-30 mins
- crucial - film will fade
- prevents spots and streaks
Dry
- prevents dust/dirt
Silver Recovery
Metallic Replacement - pass fixer in steel wool to replace silver with steel
Electrolyte Replacement - pass fixer b/t anode and cathode.
Chemical Precipitate - chemcially causes silver to precipitate out in a sludge
Film Postioning
VD/DV: head up
Lateral: Head is facing left with dorsal side up
Extremities: Toes down
Screens vs Non Screens
Latent Image
Speed
Screens
- Lower mAs
- Lower radiation
- Lower exposure time
- reduce motion
- rare-earth lanthanides for better light conversion
Latent Image - converts xrays to visible light
Non Screens
- Good for dental/bone
- No loss of detail
- longer exposure time
- Responds directly to xrays
Speed
Large Crystals
- Faster
- Less detail
- Penetrates thick tissue
- Greater light emission
Smaller Crystals
- Slower
- Better detail
- more radiation needed
Fluoroscopy
Real time
Radiography
Screen is above table
Xray tube is below table
less resolution
Uses Cadium sufide screens
Ultrasound
Things that can’t be identified on xrays
Motility
no radiation
Free fluid = good detail
Free gas = poor detail
Uses soundwaves (2mhz-10mhz)
Sound travels faster in solids, slower in gases
best in soft tissue
poor detail of bone and lungs
Ultrasound gel = eliminates air
Transducer: sound, electric energy to sound waves to electric energy
Phased Array - common transducer in vet meds
Echogenicity
Indicates liquid or solid by intensity of reflected echo
Hyperechoic - Bright
Hypoechoic - Dark
Anechoic - non echoic
Red: blood is flowing towards you
Blue: Blood is flowing away from you
C.T
Computerized Tomography
Uses radiation
fixed kVp 120
Brain, Spinal Cord, Nervous system, spine, obscure mass
Rotating xray tube. 360
Good contrast in bone
Cross sectional images
MRI
Magnetic Resonance Imaging
Good Contrast for soft tissue
Scintigraphy
Not a diagnotis tool
Need radioactive material (IV)
Low radiation
Physiology of organs
Identify lesions
Thyroid, Bone, Liver
Musculoskeletal Diseases
- Muscles
- Ligament
- Connective tissues
- Bone/Cartilage
Legg-Calve Perthes
- Necrosis of femoral head
- Blood to bone interruption
- Small dogs
- <12 months age
Panosteitis
- Patchy apperance to bone
- Inflammatory condition
- Large Dogs
- 5-14 months
Arthritis
- Inflammation in joint
- Infectious: caused by an infection
- Immune Mediated
- Erosive - Small breeds (rheumatoid)
- Nonerrosive - Large breeds
Spondylosis Deformans
- Osteophytes b/t disc columns
- too much vitamin A
Osteochondrosis Dessicans (OCD)
- Piece of Cartliage sticks out into joint
- Cartilage dies and tries to make fibrous
- Cartilage joint thickens and stops bloodsupply
- Medium-Large breeds
- 6-9 months
Hip Dysplasia
- Malformation of coxofemoral Joints
- Large dogs
- Heredity
- PennHip or OFA organization
Patellar Luxation
- displacement of patella
- Small dogs
Fibrosarcoma
- Cancer starts of in soft tissue and spreads to bone
Long bone Anatomy
Fractures
Simple Fractures
- bone splits into 2
Comminuted Fractures
- Bone splits into multiple pieces
Compound Fractures
- Open fracture
Incomplete Fractures
- aka greenstick fracture
- bone is cracked on one side
Multiple Fractures
- fractures on more than 1 sites
Joint Mouse
- Fragment of bone is joint space
Stable
- Fragments interlock
Unstale
- Fragments do not interlock
Impacted
- Fragments are pushed together shortening the bone
Condylar Fracture
- Joint fracture
Avulsion
- Bone displaced from muscle/ligament/tendon
Crepitus
- crackling sound/feel
Healing
Malformation
Deformity
Osteophytes
- Periosteal Reaction - 1st stage
- Callus Formation - 2nd stage
Malformation: Defect that occurs while bone is growing
Deformity: Abnormal alternations from previous bone
Osteophytes - bony projections aka bone spurs
Contrast
Enhances visualization
+ Contrast
- Barium or Iodinated
- Radiopaque = White
- Increase kVp 10%
- Contrast
- Gas/Air
- Radiolucent = Black
- Decrease kVp 10%
Double Contrast
- and - Contrast
- Uric acid cystoliths
Contrast Studies
Esophagram
- Esophagus ~ Stomach
- Barium orally
- Pic. during and after swallow
Upper GI Series
- Stomach, Small/Large Intestine
- 4-8mL/kg of 30-60% contrast
- Fast animal 12 hours
- 4 views at 0
- 2 views (rt & vd) at 15, 30,60,90 mins
Barium Enema
- Rectum, Colon, Cecum
- 10-15ml/kg rectally
Cystogram
- Bladder, Iodinated
Pneumocystogram
- Bladder, co2
Double Contrast Pneumocystogram
- Bladder, both
Urethrogram
- Kidney, ureter, bladder, iodinated
Excretory Urogram
- Kidney & collection system
- IV injection - iodinated or triiodinated
- Nephrogram - phase 1
- Pyelogram - phase 2
Myleography
- Spine
- Iodinated contrast
Planes
Frontal Plane: Dorsal/Ventral
Saggital Plane: Left/Right sides
Transverse: Cranial/Caudal
Median Plane: Lt./Rt. Halves
Animal Postioning
Abdomen
- Expiratory phase
- B.C.& measure: 13th rib
- Diaphram ~ femoral head
Pelvis
- FOV: part of lumbar ~ femur
- Lateral view
- VD view (Frog leg)
- Extended Projection
Cervical Spine
- FOV: Base of Skull~1st few thoracic
- DV
Thoracic Spine
- FOV: C7~L1
- BC: T7
- Measure: 7th rib
Lumbar Spine
- FOV: T13~Sacrum for lateral
- FOV: L6~Illiac crest for VD
Thorax
- Inspiratory phase
- Lookfor metastasis
- Low mAs, high kVP
- FOV 1st rib ~13th rib (VD/DV)
- FOV: manubrium~L1 (Lateral)
Skull
- FOV: tip of nose ~ base of skull
Dental
Dogs
3142
3143
Cats
3131
3121
Right Maxillary: 1
Left Maxillary: 2
Left Mandible: 3
Right Mandible: 4
Incisors: 01
Canine: 04
Premolars: 08 (Last premolar)
Molar: 09 (1st molar)
Dental machine
Non screen
Good detail
SID 16” or less
- Parallel technique
- Bisecting Technique
