X-rays

ionizing radiation

Radiography, computed tomography, and nuclear medicine all use

radiography, computed tomography, nuclear medicine

what three imaging techiques use ionizing radiation

ionizing radiation

______ is damaging to cells and may cause temporary or long term injury

sound waves, radiofrequency waves and magntic fields

Diagnostic Medical Sonography and Magnetic Resonance Imaging use

Diagnostic Medical Sonography, Magnetic Resonance Imaging

_________ are non-ionizing and are safer than ionizing

Magnetic Resonance Imaging

MRI stands for

stochastic effects

efefcts realized 10-20 years from date of exposure

non-threshold, linear response (no safe level, risk!)

stocastic effects have a __________ response

directly preportional

with radiation, risk is ___________ to dose

true

true or false: there is some risk from background radiation alone

deterministic effects

impacts seen over short periods (often HIGH doses over short time)

threshold NON-linear response (there is a specific dose required to see a response)

deterministic effects have a ________ response

cancer years later, vs immediate burn

example of a stocastic effect vs a deterministic effect

2.0Gy, 3.0Gy, 0.5Gy, 5.0Gy

Known Level of exposure for induction of burns, hair loss, acute cataract induction, and chronic induction

X-rays

radiography uses ____ to produce images

tube boils electons off which interact with metal target and produce x-rays, which penetrate tissue based on composition and provide a shadow gram

how does radiography work?

transmission (good)

no absorption

tissue/bone absorbs rays, good thing

absorption

bad radiation, no data, bad

scatter

energy of x-ray, type of tissue/material being imaged

what impacts x-ray penetration?

bright

high absorption/low penetration tissues appear

dark

less attenuating/high penetration areas appear

Fluoroscopy

________ utilizes continuous x-rays to produce a motion picture of an anatomical area

function (ex. swallowing, hip pinning)

Fluoroscopy images show _______

allows visualization of function, shows tissues not always seen

advantages of contract studies in fluoroscopy

arthrograms, most common in shoulder, knee, wrist

image procedures of the synovial joints

vasculature of UE and LE, look for embolism, aneurism, stricture/occlusion, arterial injury

peripheral angiography/venography show

femoral puncture

most common site for access of arterial system

ionizing radiation, limited soft tissue resolution

main limitations of radiography

Bone Densitometry

Dual energy X-Ray Absorptiometry (DEXA) is most common scan for

Lumbar Spine L1-L4, or Hip (may use wrist with surgery.hardware) or whole body for metabolic

Preferred sites for DEXA

number of standard deviations from the mean value of a 25 year old woman

what is a T-score?

within 1 standard deviation

normal bone is ______ T score (of mean)

between -1 to -2.5 standard deviations

osteopenia is _______ T score (of mean)

less than -2.5 standard deviations

osteoporosis is ______ T score (of mean)

T compares to “best” where z is compared to age group, many older individuals will have low bone density

why is T-score better than Z-score DEXA