Spom Imaging

Imaging TechniquesImaging Techniques

Utilize Ionizing Utilize Ionizing Don’t Utilize Don’t Utilize Radiation Radiation Ionizing RadiationIonizing Radiation

Plain FilmsPlain Films MRMR

FluoroscopyFluoroscopy USUS

CTCT

Nuclear MedicineNuclear Medicine

MammographyMammography

X-RaysX-Rays

1.1. High energy photonsHigh energy photons

2.2. Similar to visible lightSimilar to visible light

But … have a higher energy and a shorter But … have a higher energy and a shorter wavelengthwavelength

Plain FilmsPlain Films

1.1. X-ray tube shoots high energy electrons at a X-ray tube shoots high energy electrons at a target (Tungsten)target (Tungsten)

2.2. When the electrons go around the nucleus of When the electrons go around the nucleus of the Tungsten atom, the electrons lose energythe Tungsten atom, the electrons lose energy

3.3. This occurs by 2 processes: This occurs by 2 processes: Bremmstrahlung and K shell KnockoutBremmstrahlung and K shell Knockout

4.4. Change in the energy of the electron results Change in the energy of the electron results in radiation and x-ray formationin radiation and x-ray formation

Plain FilmsPlain Films

Finally, x-rays are collected on:Finally, x-rays are collected on: Photosensitive film (permanent)Photosensitive film (permanent) Digital Imaging Plate (permanent)Digital Imaging Plate (permanent) Fluoroscope (temporary)Fluoroscope (temporary)

X-RaysX-Rays

Can’t see the x-rays, only the imagesCan’t see the x-rays, only the images Image seen is that part of the patient that Image seen is that part of the patient that

blocks the x-ray beam.blocks the x-ray beam. The denser the material, the more difficult it is The denser the material, the more difficult it is

for the beam to penetrate the anatomic areafor the beam to penetrate the anatomic area

X-ray ExposureX-ray Exposure

Not all x-rays that enter the body leave it!Not all x-rays that enter the body leave it!

Absorbed x-rays can damage DNA, affecting Absorbed x-rays can damage DNA, affecting future cells, causing mutations or cell deathfuture cells, causing mutations or cell death

Keep in mind, x-rays can be diagnostic or Keep in mind, x-rays can be diagnostic or therapeutictherapeutic

X-ray Exposure continuedX-ray Exposure continued

X-ray exposure is cumulativeX-ray exposure is cumulative

It is important to assess the Risk/Benefit ratioIt is important to assess the Risk/Benefit ratio

1. Does the patient really need the study?1. Does the patient really need the study?

2. Can the study be done with other non-x-ray 2. Can the study be done with other non-x-ray diagnostic studies?diagnostic studies?

3. Can non-vital areas be shielded?3. Can non-vital areas be shielded?

DensitiesDensities

1.1. Air - Lungs, Bowel gasAir - Lungs, Bowel gas

2.2. Fat - OmentumFat - Omentum

3.3. Soft tissue - Muscle, Solid OrgansSoft tissue - Muscle, Solid Organs

4.4. Bone - Skeleton, CalcificationsBone - Skeleton, Calcifications

5.5. Metal - Hardware, ContrastMetal - Hardware, Contrast

Inspiration Expiration

Chest X-Ray FeaturesChest X-Ray Features

1.1. Symmetry - unilateral vs. bilateralSymmetry - unilateral vs. bilateral

2.2. Location - upper, middle, lower, peripheral, Location - upper, middle, lower, peripheral, central, anterior, posteriorcentral, anterior, posterior

3.3. SizeSize

4.4. Number - Single, MultipleNumber - Single, Multiple

5.5. Borders - Smooth, IrregularBorders - Smooth, Irregular

6.6. Density - Solid, Air, or Fluid filled, or Density - Solid, Air, or Fluid filled, or CombinationCombination

FluoroscopyFluoroscopy

Live images obtained while a procedure Live images obtained while a procedure or maneuver is being performed.or maneuver is being performed.

X-ray beamX-ray beam patient patientX-ray strikes X-ray strikes

coupled coupled Fluorescent Plate Fluorescent Plate Image IntensifierImage Intensifier

coupled coupled TV CameraTV Camera

Image

UltrasoundUltrasound

High frequency sound waves sent into High frequency sound waves sent into tissue and the reflected echoes tissue and the reflected echoes create an image.create an image.

Real time images-demonstrate motion Real time images-demonstrate motion –ex. fetal heart beat–ex. fetal heart beat

Doppler images-demonstrate speed Doppler images-demonstrate speed and direction of flow in a vessel – ex. and direction of flow in a vessel – ex. carotid arterycarotid artery

Ultrasound ContinuedUltrasound Continued

Thorax - Heart-wall thickness, Thorax - Heart-wall thickness, motion, valvesmotion, valves

Abdomen - Liver, spleen, pancreas, Abdomen - Liver, spleen, pancreas, kidneys, masses, solid, cystic, stoneskidneys, masses, solid, cystic, stones

Pelvis - Female-Ovaries, uterus, fetus,Pelvis - Female-Ovaries, uterus, fetus,

Male-Prostate, massesMale-Prostate, masses

Vasculature - Aorta-AneurysmsVasculature - Aorta-Aneurysms

Peripheral vessels-DVTPeripheral vessels-DVT

Ultrasound ContinuedUltrasound Continued

Densities:Densities:

Black - anechoic - low density - fluidBlack - anechoic - low density - fluid

Gray - echogenic - medium density - Gray - echogenic - medium density - soft tissuesoft tissue

White - hyperechoic - high density - White - hyperechoic - high density - calciumcalcium

CTCT

In the gantry, there’s a series of small x-ray In the gantry, there’s a series of small x-ray sensors which rotate. They take multiple sensors which rotate. They take multiple x-ray pictures from various angles. x-ray pictures from various angles. Computers interpret the data, compiling Computers interpret the data, compiling the many images obtained. The images the many images obtained. The images appear as cross-sectional slices obtained appear as cross-sectional slices obtained at many levels.at many levels.

CT continuedCT continued

AdvantagesAdvantages

1.1. Almost all anatomic areas visibleAlmost all anatomic areas visible

2.2. Use with or without oral/IV Use with or without oral/IV contrastcontrast

3.3. QuickQuick

4.4. Can differentiate different Can differentiate different densities-air/fluid/soft tissue/bonedensities-air/fluid/soft tissue/bone


DisadvantagesDisadvantages

1.1. Ionizing RadiationIonizing Radiation

2.2. CostCost

3.3. Not available at all institutionsNot available at all institutions

4.4. May be hampered by metal/star May be hampered by metal/star artifactartifact


Densities- Hounsfield UnitsDensities- Hounsfield Units

Low Attenuation - black (air)Low Attenuation - black (air)

High Attenuation - white (bone)High Attenuation - white (bone)

CT/MRCT/MR

Key Features to AssessKey Features to Assess AsymmetryAsymmetry Masses or mass effectMasses or mass effect Midline shiftMidline shift Fluid collectionsFluid collections

CT/MR continuedCT/MR continued CT AdvantagesCT Advantages AvailabilityAvailability SpeedSpeed CostCost Can detect calcium and Can detect calcium and acute bleeds more easilyacute bleeds more easily Accommodates patient Accommodates patient monitoring equipmentmonitoring equipment

MR AdvantagesMR AdvantagesMultiplanar images (axial, Multiplanar images (axial, coronal, sagittal, oblique)coronal, sagittal, oblique)Greater gray/white Greater gray/white differentiationdifferentiationMore detailed anatomyMore detailed anatomyBetter visualization of Better visualization of subacute and chronic subacute and chronic bleeds and spinal cord bleeds and spinal cord compression (trauma or compression (trauma or mets)mets)

MRMR

1.1. MR utilizes a magnetic field and radiofrequency MR utilizes a magnetic field and radiofrequency antennas (coils) to obtain an imageantennas (coils) to obtain an image

2.2. The magnetic field causes all of the protons in the The magnetic field causes all of the protons in the patient’s body to line uppatient’s body to line up

3.3. Then, a high frequency magnetic pulse shifts them Then, a high frequency magnetic pulse shifts them from their straight positionsfrom their straight positions

4.4. A special antenna listens for the resonance signal A special antenna listens for the resonance signal each proton gives offeach proton gives off

5.5. Characteristically, they go back to their original Characteristically, they go back to their original positionspositions

MRMR

TR/TETR/TE

MarrowMarrow

CSF/H20/DiscCSF/H20/Disc

TR - Repetition Time - length of time needed for TR - Repetition Time - length of time needed for protons to realign protons to realign

TE - Echo Time - measure of time for energy absorbed TE - Echo Time - measure of time for energy absorbed from the radiowave pulse to be reabsorbedfrom the radiowave pulse to be reabsorbed

T1T1

ShortShort

BrightBright

DarkDark

T2T2

LongLong

DarkDark

BrightBright

MRMR

Dark ( SI )Dark ( SI )

1.1. AirAir

2.2. Cortical BoneCortical Bone

3.3. Flowing BloodFlowing Blood

4.4. Fibrous TissueFibrous Tissue

5.5. H2O/ Edema (T1)H2O/ Edema (T1)

Bright Bright ( SI )( SI )

1.1. FatFat

2.2. HemorrhageHemorrhage

3.3. H2O/ Edema (T2)H2O/ Edema (T2)

MR PrecautionsMR Precautions

Strong Magnetic Field-Strong Magnetic Field-

Determine whether patients have:Determine whether patients have:

aneurysm clips-headaneurysm clips-head

pacemakerspacemakers

artificial valvesartificial valves

exposure to metal shardsexposure to metal shards

Interventional RadiologyInterventional RadiologyCan be diagnostic or therapeutic Can be diagnostic or therapeutic • Procedures:Procedures:Angiography-vessel visualizationAngiography-vessel visualization

Tube, line, stent, device placementTube, line, stent, device placement

BiopsyBiopsy• Complications:Complications:

Hemorrhage, embolus, infectionHemorrhage, embolus, infection

Interventional Radiology continuedInterventional Radiology continued

Radiopaque dye (absorbs the x-ray beam) is Radiopaque dye (absorbs the x-ray beam) is administered via a catheter. administered via a catheter.

X-ray images reveal the anatomy to be normal X-ray images reveal the anatomy to be normal or abnormal.or abnormal.

Abnormal features include stenosis (blockage), Abnormal features include stenosis (blockage), abnormal vessels (AVM), and Tumor Blushabnormal vessels (AVM), and Tumor Blush

Interventional Radiology continuedInterventional Radiology continued

ContrastContrast

1.1. Same dye used in other x-ray studies, Same dye used in other x-ray studies, IVP’s, CT’sIVP’s, CT’s

2.2. Dye-clearDye-clear

3.3. Metallic tasteMetallic taste

4.4. Warm flush feelingWarm flush feeling

5.5. NauseaNausea

6.6. Ask about prior administration, Ask about prior administration, allergies, and renal functionallergies, and renal function

Nuclear MedicineNuclear Medicine

A small amount of a radioactive isotope is A small amount of a radioactive isotope is administered to the patient – injected administered to the patient – injected intravenously, inhaled or swallowed. These intravenously, inhaled or swallowed. These isotopes attach themselves to certain isotopes attach themselves to certain molecules in the body. Images are obtained to molecules in the body. Images are obtained to determine the abnormality.determine the abnormality.

Nuclear Medicine continuedNuclear Medicine continued

Bone scan Tec 99m – 4 hoursBone scan Tec 99m – 4 hours

Same amount of radiation as a CXRSame amount of radiation as a CXR

Isotope excreted in urineIsotope excreted in urine

Images obtained initially and then 3 hours later. Images obtained initially and then 3 hours later. Actual scanning time 30-40 minutesActual scanning time 30-40 minutes


Bone Scan Bone Scan Increased uptake in:Increased uptake in:

Acute FracturesAcute Fractures

Metastatic DiseaseMetastatic Disease

Growth PlatesGrowth Plates


ScansScansGallium – infectionGallium – infectionHepatobiliary – evaluate liver and gallbladder Hepatobiliary – evaluate liver and gallbladder

function and anatomyfunction and anatomyLiver/Spleen – shape, size, position of organsLiver/Spleen – shape, size, position of organsThyroid scans – special instructions-Thyroid scans – special instructions-

discontinue thyroid medication, discontinue thyroid medication, no I.V. contrast, no seafood or no I.V. contrast, no seafood or Iodine containing productsIodine containing products


V/Q scan evaluate air and blood flow to lungsV/Q scan evaluate air and blood flow to lungs

TC99m-MAA TC99m-MAA injected intravenouslyinjected intravenously

Xenon-133Xenon-133 inhaled via maskinhaled via mask

Test for PE, acute or chronic, pre-op lung Test for PE, acute or chronic, pre-op lung reserves, effects of granulomatous lung reserves, effects of granulomatous lung disease, post-op complications, emphysema, disease, post-op complications, emphysema, heart shunts, congenital abnormalitiesheart shunts, congenital abnormalities

MammographyMammography

1.1. Film/Screen Technique - lower Film/Screen Technique - lower radiation doseradiation dose

2.2. 2 views – craniocaudal, cephalad2 views – craniocaudal, cephalad

3.3. Initial screening at age 40 unless Initial screening at age 40 unless high risk or symptomatichigh risk or symptomatic

4.4. Follow up with Ultrasound, MR (?)Follow up with Ultrasound, MR (?)

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Spom Imaging