lesson 1 Flashcards
- they design the equipment that emits radiation
- they always check for radiation
- Developed administrative protocols (rules)
- Practice ALARA
Health physicists or radiation scientist
The more you give radiation to the patient the more higher the side effects to the patient
Linear threshold
benefits over the risk
Justification
what are the limitation
time/distance/shielding
Three cardinal principles of radiation
protection
- develop for nuclear activities
- useful application in diagnostic radiology
- by observing the ff. Radiation exposure can
be minimized
keep as short as possible
Time
maintain a large BLANK b/n
the source of radiation and the exposed
person
Distance
for the area that is no need for
exposure for the other body parts
Shielding
Minimize time benefits
- to reduce motion blur
- to reduce patient and personnel exposure
Equation exposure =
exposure rate X Exposure time
sequencing on off rather than continuous
on during examination ( repeated up and
down motion - high-quality examination
and reduce patient exposure
Fluoroscopic foot switch/ dead man
switch
<5 mins
Fluoro procedure-
> 5mins
Interventional radiology procedure
Best method to reduce radiation
distance between source of rad and the
person increase = decrease radiation
exposure
x ray tube target is the?
Point source
like scatter radiation na
galing sa patient
Extended source
FFD
other term sa SID focal point to film
distance
Inverse square law
Distance increase dose will decrease
Formula for inverse square law
intensity 1/ intensity 2 =
distance 2^2/ Distance 1^2
lines that represent positions of equal
radiation exposure in the fluoroscopy room
Iso exposure lines
Used to estimate the amount that a protective barrier reduces radiation intensity
1TVL= 3.3 HVL constant value
is the thickness of absorbing material to
reduce the radiation intensity to half of its
original value
Half value layer- filtration
thickness of material that will reduce the radiation intensity to one-tenth of its original
value
Tenth- value layer
thickness of a protective apron
0.5mm Pb thickness
Is the maximum dose of radiation in
light present knowledge produces no
significant radiation effects.
Maximum permissible dose (MPD)
no somatic
or genetic responses should occur
Radiation dose below MPD
risk is small but not zero
Doses at level of MPD
- regardless of dose, there is an effect
- considered the level of exposure acceptable as an occupational hazard
- model for rad protection
linear non threshold
Students under 18 yrs old MPD
0.1rem(100mrem/yr)(1mSv/yr)
Non-occupational exposure MPD
0.5rem (500mrem)(5mSv)
Pregnant RT MPD
- Not exceed 0.5rem (500mrem)(5mSv) yearly
- If per month:50mrem(0.5mSv)
0.5rem (500mrem)
(5msv)
Fetus MPD
Radiation dose units
- Gyt
- rad
- energy
absorbed of patient
Radiation exposure units
- Gya
- roentengen
- intensity in air
Public and occupational exposure units
- rem
- radiation (roentgen) equivalent
man
