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Imaging Quiz 1

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moonlup's version from 2017-09-08 13:46

Section 1

Question Answer
Cathode Chargenegative
Anode Chargepositive
Which way do electrons travel in an xray tube?From negatively charged cathode to positively charged and rotating anode
What controls the amount of electrons released by the cathode?current, controlled by mA. This controls the quantity of radiation
What are the two ways xrays are produced?characteristic/collisional radiation and radiative/Bremsstrahlung radiation
What controls the energy of xrays produced?energy of electrons striking the anode, a function of the kVp
How much of the electron energy striking the anode becomes xrays?10%, the rest becomes heat
What determines effective focal spot?filament size and focal spot angle
mAsmilliAmps seconds, the number of xrays
kVpkiloVoltage peak, the energy of xrays
What determines xray exposure?kVp & mAs
Why collimate?decrease scatter and improve image quality
photoelectric effectejected photoelectrons in tissue can cause ionization
coherent scatterelectrons maintain energy but change direction
Compton scatterelectrons decreased in energy
Grid ratioheight to width of lead strips
Grid FactormAs increase needed to compensate for grid absorption
Inverse Square Lawat twice the distance there is a quarter of the xrays available
Film densitydegree of film blackness
Intensifying Screenphosphor crystals that transform xrays to light, which reduces xrays needed for an image
Fast Screenlow resolution, low exposure
Slow/Detail Screenhigh resolution, high exposure
few shades of greyhigh contrast
many shade of greylow contrast
setting for high contrast imagehigh mAs/low kVp
setting for low contrast imagelow mAs/high kVp
Contrast desired for abdomenhigh contrast
Contrast desired for thoraxlow contrast
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Section 2

Question Answer
Artifactunwanted optical density
how do you minimize motion blurshort exposure times, peak inspiration
Distortionunequal magnification of what you're imaging
How does radiation kill cells?affects H2O and forms radicals that then interact with other molecules and kill the cell
Radiosensitive tissuesrapidly dividing tissues: marrow, GI, Gonads, Lung, Skin/mm, Neuro, fetus, breast, liver, thyroid
Deterministic effectsdose threshold adverse effects, ie radiation induced cataracts
Stochastic effectsrandom adverse effects, ie radiation induced cancer
SI unit for absorbed dose of radiationGray/Gy
1 Gy1 joule / kg of tissue
ICRP radiation limits20 mSv / year
ALARAas low as reasonably achievable
Sources of exposurePrimary, Scattered, and Leaked radiation
How much radiation do lead aprons absorb?90% of scattered
TLDthermoluminescence dosimetry: beta, gamma, xray
OSLoptically stimulated luminance: beta, gamma, xray
pocket dosimetergamma and xray
Lead to concrete blocking ratio1mm Pb/10cm concrete
memorize

Section 3

Question Answer
Xray ID requirementsName, Owner Name, Case No., Date, Subject of Image
Where does the limb marker go?dorso/cranial or lateral aspect
EpiphysisEnd of long bone distal to physis
MetaphysisNeck of long bone proximal of physis
DiaphysisShaft of long bone
PhysisGrowth plate
ApophysisProtuberance of bone
Woven Bonehaphazard bone structure in fetus and bone repair
Lamellar BoneCortical and cancellous/trabecular bone, dense, seen in late repair
Intramembranous ossificationflat bone development, periosteal membrane around diaphysis lays down concentric laminae
Endochondral ossificationcartilage models replaced by bone
Physeal Platethe physis
Centers of Ossification for Long BonesPrimary (midpoint), Secondary (physis), Tertiary (apophysis)
MCPmedial coronoid process
Types of Periosteal reactionSmooth, Lamellar, Brush-border/Palisading, Radiating, Amorphous
Codman Triangleperiosteal reaction seen proximal to bone tumor
distinct vs indistinct/permeative zone of transitionbenign vs malignant
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Section 4

Question Answer
How much mineral content must be lost to be seen on radiographs?30-60%
Generalized pattern of destruction causesSerum Ca levels, hyperparathyroidism, poor nutrition, disuse/atrophy, hyperadrenocorticism, osteopenia, osteomalacia
Localized pattern of destruction causestumor, infection, indicates intact blood supply
How long does it take for bone lysis to be seen?7-10 days after insult
most common bone neoplasiaosteosarcoma (primary monostotic neoplasia), occurs on bone surface of prox humerus/tibia and distal radius/femur, metastasise to lungs
2nd most common malignant bone tumorchondrosarcoma, occurs in flat bones, metastasise to LNs, then lungs
Primary polyostotic neoplasias aremultiple myeloma, bone lymphoma
Malignant transformationneoplasia at previous fracture site, mostly diaphyseal
Rickets/Vit D deficiency results inphyses widening and metaphyses flaring
Metaphyseal bone tissue destruction caused byprimary bone tumor, hypertrophic osteodystrophy, hematogenous bone infection (immature), metastatic bone tumor
Diaphyseal bone tissue destruction caused bymetastatic bone tumor, hematogenous bone infection (mature)
Cortical involvement means what?aggressive bone lesion
Geographic patternsingle area/collection of small areas, clear margins, mb thinned cortex,mb sclerotic borders, usually benign
Moth-eaten patternmultiple varying sizes, less defined, irregular cortex erosion, malignant
Permeative patternnumerous pinpoint lesions, mainly recognized in cortex, irregular cortex erosion, highly aggressive
Panosteitis density increases arefocal, polyostotic
Metastatic tumor density increases aremultifocal, mono/polyostotic
Bone density increase that is focal and monostotic with single lesionhealing fracture or bone infarct
How fast is progression in malignant bone lesions?~3 weeks
memorize

Section 5

Question Answer
When can fracture lines be seen?when parallel to xray beam
Closed vs open/compoundskin broken or not, look for gas
Simple vs comminutedOne break vs 3 or more pieces
Multiplemore than one fracture lines that do not connect
Segmentaltwo or more fracture lines in same bone
Transverse, Oblique, Spiral, Longitudinal, IrregularHorizontal, Diagonal, Curved Diagonal, Vertical
Complete vs IncompleteOne cortex or two, greenstick
Chip Fracture1 articular margin
Slab Fracture2 articulations
Articular vs Non-ArticularIn the joint or not
Avulsion FractureTubercle/Process broken off or SH7
Fatigue/Stress Fractureone cortex only, from repetitive minor trauma
Impaction/Compression FractureSH5
Fracture Sub/LuxationWhere did it move? Proximal/Distal/Medial etc. Describe distal portion.
Salter-Harris FracturesTypes 1-7, Physeal Fractures
Pathological Fracturebone around fracture not normal, fracture secondary to underlying bone pathology
Fracture healing stepsends blur, gap widens, callus forms, gap bridges, callus remodels, gap disappears
Time for fracture healing of clean break<3month animal = 1 month, >1year = 5-12 months
Malunion can lead tonon-anatomic reduction of fracture, atrophic non-union
memorize

Section 6

Question Answer
ectrodactylymissing central digit/s
polydactylyexcess digits
syndactylytwo or more digits fused
panosteitisnew medullary bone, likes nutrient foramen, results in coarse, thickened trabeculae
HODhypertrophic osteodystrophy, aka metaphyseal osteopathy
Hypertrophic osteodystrophy signsearly lytic zone in metaphysis w/ sclerotic band, extracortical cuff forms. Looks like double physis
Osteopetrosisincreased bone opacity, esp medulla. Form of osteodysplasia due to deficient osteoclasts.
Osteochondral dysplasiaepiphysis mineralization is delayed, may be rounded, sclerotic, and flared metaphysis
Scottish Fold Osteochondrodysplasiaautosomal dominant defective cartilage maturation, likes distal joints and ankylosis them
Osteochondromatosisbenign proliferative disease of bone and cartilage (the rib and transverse spine dog). Chondrocytes don't become osteoblasts and proliferate
Retained cartilage Coreseen in distal ulna, cone shaped radiolucency. Can delay ulnar growth if large
Most commonly injured physis in dogsdistal ulnar physis
Distal ulnar physis injury results insevere angular limb deformity
Varus vs valgusmedial vs lateral
Legg-Calve-Perthes diseaseyoung small breed dogs, ischemic aseptic necrosis of subchondral femoral head, usually unilateral
Osteochondrosis/chondritis / dissecansyoung large breed dogs. cartilage necrosis or proliferation with failure to ossify, failure of normal endochondral ossification, seen in weight bearing joint surface of shoulder, stifle, elbow, tarsus. usually bilateral.
OCD Elbowsclerosis of medial humeral condyle
memorize

Section 7

Question Answer
Joint effusionabnormal filling of joint
Periarticular swellingjoint capsule thickening, ST swelling
Joint congruencyarticular surface should be in contact, only separated evenly by ST articular cartilage and synovial fluid
Joint sub/luxationSub is reduced contact area, Lux is no longer in contact
Joint osteophytesbony outgrowth where articular cartilage is worn, defining feature of osteoarthritis
Defining feature of osteoarthritisosteophytes
Joint entheseophytesossification of tendon/ligament/joint capsule attachments
DJDDegenerative Joint Disease, aka osteoarthritis or osteoarthrosis
What happens in DJD?slow progressive disease of synovial joints with joint effusion, osteophytes, subchondral sclerosis, intra-articular mineralization, diminished range of motion
periarticular mineralised bodiesdue to chip fractures, osteochondral fragments, accessory ossification centers, mineralised cartilage etc
elbow dysplasia is due toununited anconeal process (UAP), fragmented medial coronoid process (FCP), OC/OCD
What results in dysplasia?excess joint laxity
Norberg angledogs >105, cats >95
Best view for UAPflexed mediolateral view
Feline rheumatoid-like arthritiserosive feline noninfectious polyarthritis, subchondral and perichondral bone erosion, ligament insertion destruction, subluxation of extremities small joints
Feline periosteal proliferative arthritisfever malaise, periarticular soft tissue swelling and regional lymphadenomegaly, extensive entheseophytes and narrowed joint spaces
memorize