Radiation Safety and Physics

what is ALARA

as low as reasonably achievable, maintain exposures to ionizing radiation as far below dose limits as practical

how do we accomplish ALARA

shielding

distance

time

what type of radiation is lead PPE mean to protect from

scatter

doubling distance away from beam will reduce exposure by a factor of

4

what is collimation

how narrow the machine is set for the primary beam

what is dosimeter badge used for

to monitor how well the occupational radiation safety program is followed

worn in workplace

what are some properties of X-rays

no charge, no mass

travel at speed of light

invisible, cannot be felt

travel in straight line

part of spectrum of electromagnetic radiation

how are x-rays made

electric current passed through filament to start

cathode is negatively charged and sends electrons surging toward rotating anode

number of electrons produced influenced by amount of electric current passed through filament

what do we adjust to get best xrays

adjust mA(s) and kVp

adjusting mAs is helpful for

increasing control

increases quantity of xray produced

increasing kVp will

increase energy AND number of xrays produced

kVp and mAs will be set up based on patient

size and body part that needs to be obtained

how is grey scale made

different parts of the body appear different on radiograph

grid helps to

filter out scatter radiation and allow a better image to be recorded