Imaging Highlights

PROJECTION Refers to the path the beam takes through part Anteroposterior projection (AP) Beam enters the front surface and exits the back surface of the part Posteroanterior projection (PA) Beam enters the back and exits the front of the part AP projection in supine position PA projection in prone position

L lateral erect position R to L lateral projection Lateral Projections Normally the positioning terminology is used rather than projection torso and head Right to left lateral projection Left to right lateral projection extremities Mediolateral projection Lateromedial projection L lateral erect position R to L lateral projection

Oblique Projections Normally the positioning terminology is used example RPO position = right anterior to right posterior projection (oblique AP)

Radiographpy vs Nuclear Medicine Radiography – source of radiation is external. Gamma rays pass through body and form radiograph Nuclear Medicine – source of radiation is radiopharmaceutical taken internally. X-rays pass out of body and form scan image.

Ionization Ability of x-rays to change substances thru which they pass Used to make radiographs and treat cancer May cause cell damage and even death

Nuclear Scan Can give picture of both structure and function Use radiopharma-ceutical to produce image

Common Scans Bone – fractures, tumors, inflammation, bone growth Brain – tumors, blood flow Liver – cirrhosis, hepatitis, tumors, cysts, abscesses Lung – blood clots, tumors Thyroid – function, tumors

Radioimmunoassay Mix blood with radioactive substance to determine specific blood protein concentrations Find antibodies and antigens (titers)

Radiation Therapy Treatment of CA with external radiation Stereotactic – focusing multiple beams at the same spot

Teletherapy vs Bradytherapy Teletherapy – radiation source is external Bradytherapy – radiation source is internal

Tomography Imaging method that produces tomes (cross sections) of body along any plane

CAT vs PET CAT – 2D tomes are reconstructed to show 3D images of structure PET – radiopharmecuticals are used to give 2D and 3D images of function

Magnetic Resonance Imaging Media – radio waves and a strong magnetic field Gives good image of soft tissues Cannot use if metal is implanted in body

Sonogram Media – sound waves Gives image of deep structures Only imaging procedure safe for fetus

Thermogram Media – infrared camera captures surface body heat Newer forms relate metabolic activity (function) to heat given off

Contrast Medium Radio-opaque substance used to make hard-to-see structure show up on image Used in CAT scans and fluoroscopy

Radio-opaque vs Radiolucent Block x-rays Shows up as light color Radiolucent – Passes x-rays thru’ Shows up as dark color

Fluoroscopy Visualization of moving structures Used with radio-opaque substances