Exam 2 - Nuclear Imaging Modalities

what do nuclear scans use to see structures and functions inside your body

radioactive substances

what kind of camera do nuclear scans use to detect radioactivity

gamma camera

nuclear imaging uses radioactive materials combined with a ___ molecule called radio_____ or radio_____

carrier, radiopharmaceuticals, radiotracers

what does nuclear imaging focus on

processes within the body such as metabolism and osteoBLASTIC activity

how are radiotracers usually given? what are some alternate administrative routes?

injection

oral, inhaled

a the radiotracer decays or gets metabolized, what does it release?

gamma ray

what classifies a finding as critical when using nuclear imaging

asymmetrical pattern

what are the more common radiotracers

technetium-99m

FDG-18

what radiotracer is used to detect cancer cells? why?

FDG-18, cancer cells uptake a lot of glucose

which radiotracers are tagged onto white blood cells within the patient to detect areas of inflammation and infection

technetium-99 and indium-111

what radiotracer is used to assess thyroid function

iodine-123 or iodine-131

what are the 3 types of nuclear imaging

bone scan

VQ scan

PET scan

what is the nuclear imaging form that has the highest sensitivity, specificity, and accuracy for detecting skeletal metastatic disease

FDG PET/CT

what are benefits of nuclear imgaing

very sensitive, cellular level function, find disease in early stages, target tx to specific cells, monitor response to tx

what are risks of nuclear imaging

1. slight pain and redness from injection

2. damage to cells or tissue from radiation

3. transmission of radiation through breastmilk to infant

what is the aka of bone scan

skeletal scintigraphy

what is a bone scan assessing

bone cellular activity

NOT DENSITY

what radiotracer is used by a bone scan

technetium-99m

which radiotracer is used in 80% of nuclear medicine procedures worldwide

technetium-99

in a bone scan, what are the areas of greater intensity called? what does this mean in relation to metabolic activity?

hot spots

highly metabolic, lots of uptake of the radiotracer

in a bone scan, what are the areas of lower intensity called? what does this mean in relation to metabolic activity?

cold spots

avascular regions, low metabolic activity

does technetium-99 assess osteoclastic or osteoblastic activity

osteoblastic

is osteoblastic activity associated with lytic or blastic growth

blastic

what are some common indications for the use of a bone scan

1. metastatic disease

2. differentiation btwn osteomyelitis and cellulitis

3. determination of bone variability, infxn, avascular necrosis

4. evaluation of fractures, prosthetic joints

5. biopsy site determination

6. bone pain

what are the radiotracer kinetic phases

1. flow phase

2. blood pool phase

3. delayed phase

4. delayed/delayed phase

what occurs in the flow phase

1 minutes after injection demonstrates perfusion/bld flow

what occurs in blood pool phase

5 minutes after injection

demonstrates blood pool (balance btwn plasma and interstitium)

what occurs in the delayed phase

obtained 2-4 hours later

degree of uptake depends on blood flow and rate of new bone formation

what occurs in delayed/delayed phase

obtained 24 hours after injection

static image

what is a VQ scan

ventilation perfusion

examination of the lungs and pulmonary vasculature

ventilation is ___% greater at the base of the lung than at the apex of the lungs

50

what radiotracers are utilized in a VQ scan

aerosols - tech-99, DTPA

in a VQ scan, the patient is imaged in the upright position in 3 phases, what are these phases?

initial breath

equilibrium

washout

what anatomy is assessed with a VQ scan

cardiovascular - pulmonary circulation, alveolar capillaries

respiratory system - alveoli, alveolar sacs, alveolar ducts, respiratory bronchioles

what does a VQ scan evaluate

airflow and blood flow in the lungs

what are VQ scans used for

1. diagnosis of a suspected pulmonary embolus

2. assessment of regional lung function

3. quantify right to left shunts

what does PET stand for

position emission tomography

what can PET scan reveal that other imaging tests cannot

function of an organ or tissue

what is the radiotracer used for PET scans

f-18 FDG

F-18 FDG is a glucose analogue, will this be an issue for diabetic patients?

no, it will not spike blood sugar

why is F-18 FDG a particularly good tracer

stays trapped within metabolically active cells

normal uptake of F-18 FDG is found in what organs

brain, heart, liver, and renal system

what imaging is often combined with PET and SPECT scans

CT

combination of PET/SPECT and CT allow a correlation between ____ and ____ imaging also known as hybrid imaging

functional, anatomical

what are some general benefits of hybrid imaging

increased diagnostic accuracy

individualized tx

precise monitoring of interventions

clinical indications for PET scan of the brain include identification of ___ associated with epileptic seizures and evaluation of suspected _____

foci, alzheimer dementia

clinical indications for PET scan of whole body include evaluation of patients with ____ and cancer staging and surveillance most likely of the ___ type

fever of unknown origin, lytic

clinical indications for PET scan of cardiac system includes identification of viable and ischemic ___

myocardium