Intro To radiology

Microwaves ultrasounds, Mri, uses?

nonionizing rays

ionizing vs nonionzing

ionizing knocks electrons out of atoms

low voltage circuit

• filament circuit

• supplies current to heat filament

• step down transformer lowers voltage

• releases electrons

high voltage circuit

• tube current

• accelerates electrons to produce x rays

• step up transofmer increases voltage

alumunin filter

blocks or absorbs X rays = safer beam

controlling factors in radiation production

• voltage: kVp: quality

• Tube current: quanitity

• exposure time

tube current

mA

• Flow / amt of electrons thru tube from cathode to anode

• MA * time (s) = MAS

• increase in MAS, increase in density = more black

Tube voltage peak

• energy of electrons (penetrating power)

• amount of KV applied to focusing cup and target

• increase = beam quality of photons and speed of electrons

best KVP for imaging teeth

• 60-70 KVP

MA is set to what at marquette? How manipulate?

7/8, time

main type of x ray radiation produced in tube

Bremsstrahlung

characteristic radiation

amount of radiation releases corresponds to specific target elements binding energy

• tungesten target: 70 kvp

• monoenergetic

X ray radiations with matter (3)

• compton radiation: most common

  • outer shell interaction → scattered photon + fog

• Coherent radiation: low energy, changes direction, no inionization, minimal impact

• Photoelectric effect

  • Inner shell interaction, full energy absorption, = great energy contrast

attentuation

where different tissues absorb x rays, at different rates, affecting image contrast

number one safety concern (most detrimental)

Scatter radiation

factors that boost scatter (4)

• higher kVp or MAS

• larger field size

• thicker body parts

• high atomic number