BASIC CONCEPTS How much do you already know?

????QUESTIONS??? n MATTER n Occupies_____________ n is a material substance n Has________and shape n Building blocks of matter are_______and __________.

????QUESTIONS??? n MATTER n The primary characteristic of matter is _____________ n Mass is the quantity or quality of an object? n ANSWER…QUANTITY n Does mass change when matter changes? n Give an example of a change of matter.

????QUESTIONS??? n WEIGHT n is the mass of matter in an object in ? n Why do we weigh less on the moon than on earth?

Types of energy (joules or eV) n Potential n Kinetic n Chemical n Electrical n Thermal n Nuclear n Electromagnetic

RADIATION n ENERGY EMITTED AND TRANSFERRED THROUGH SPACE n PIANO STRING=RADIATE SOUND n RIPPLES OR WAVES=WAVES RADIATE

IONIZING RADIATION(AGAIN!!!) n Removes orbital electron from atom n this electron can disrupt surrounding atoms by transferring energy to them. n This renegade(free) electron- negative ion n The atom that lost the electron- positive ion n negative ion & positive ion = ion pair

What two forms of electromagnetic radiation ionize matter? X-rays Gamma rays

What two particulate forms of radiation ionize matter? alpha beta

SOURCES OF RADIATION HARMFUL TO HUMANS n Natural – Cosmic – Terrestrial – Naturally occurring radionucleides in the human body n Manmade – medical x-rays – nuclear power plants – industrial sources – watch dials* – smoke detectors* – TV* – Airport surveillance systems*

DID YOU KNOW? n Naturally + man-made radiation occurring radiation contributes 360 mrads to the average absorbed dose to humans. n Diagnostic x-rays make up the largest source of man-made radiation (39 mrem per year-50 mrem per year)

IN THE EARLY YEARS OF USING X-RAYS n Skin damage (erythema) n loss of hair (alopecia) n low red blood cell counts(anemia) n INJURIES DUE TO n low energy radiation n looooonnnngggg exposure times (30 minutes!!!!!!!!!!!!!!!)

REDUCTION TO RADIATION EXPOSURE n Coolidge tube (Hot-cathode x-ray tube) – vacuum tube – intensity and energy to be selected (1913) Snook transformer High voltage power, induction coils (1910) Potter-bucky grid (1921)

PROTECTIVE APPAREL WAS DEVELOPED WHEN IT WAS NOTED THAT RADIOLOGISTS WERE DEVELOPING AT A HIGH RATE OF LEUKEMIA AND APLASTIC ANEMIA

Effects of radiation n Early blood changes decreased sperm count n Latent cancer changes possible genetic effects

REGULATION HISTORY n ICRP developed ALARA Radiation must have a benefit Dose should not exceed limits for specific circumstances

REGULATION HISTORY n NCRP established limits for radiation exposures for radiation workers and non-radiation workers limits were to minimize potential harm

CARDINAL PRINCIPLES OF RADIATION PROTECTION TDSTDS

DEVICES FOR MINIMIZING RADIATION TO PT/WORKER n Filtration n collimation n Intensifying screen n Protective barriers n Protective apparel n Technical factors (Highest optimal kVp, shortest time)

“The risk of radiation exposure in diagnostic imaging departments is minimal. Radiography is now considered a radiation safe occupation.” RADIOLOGIC SCIENCE FOR TECHNOLOGISTS,Stewart Bushong, 1997 Page 7