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Flashcards in Radiation Protection Deck (62)
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1
Q

radiation that has the ability to make an atom a charged particle

A

ionizing radiation

2
Q

has to have mass

doesn’t travel far

A

particulate radiation

3
Q

what do we treat superficial with?

A

electrons

4
Q

how do we treat deeper?

A

photons

5
Q

energy and wavelength are ___ proportional

A

inversely

6
Q

two major groups of radiation in rad therapy

A

external beam

brachytherapy

7
Q

External beam:

A

linear accelerators/cobalt 60 machines

produce x-rays, gamma rays, and electrons

8
Q

Brachytherapy sources:

A

137Cs, 192Ir, 125I

emit gamma rays, x-rays, alpha particles, and beta particles

9
Q

example of alpha particles

A

helium nuclei

2 protons, 2 neutrons

10
Q

alpha particles have a ___ LET

A

high

11
Q

How do alpha particles do damage?

A

They have to get inside of you

12
Q

how are alpha particles emitted?

A

from unstable nuclei
comes from nucleus
ex) radium or radon

13
Q

where are beta particles edited from?

A

the nucleus

14
Q

beta particles can be _____ or ______ charged

A

negative, positive

15
Q

What is the rest mass of an electron?

A

.511 MeV

rest mass of an electron

16
Q

how are beta particles best shielded?

A

plastic or glass

17
Q

what equation is the photoelectric effect dependent on

A

z^3/e^3

18
Q

what is the difference in x-rays and gamma rays?

A

gamma rays- nucleus

x-rays- orbitals

19
Q

what percent of X-ray interaction is brems?

A

85%

20
Q

what percent of x-ray interactions is characteristic?

A

15%

21
Q

What are the sources of radiation?

A
  • natural background

- man made

22
Q

What are the natural background sources of radiation?

A
  • cosmic: from space
  • terrestrial: from ground
  • internal exposure: radioactive material in body
23
Q

What is an ex. of terrestrial radiation?

A

radon

2nd most common for lung cancer

24
Q

Units for exposure

A

traditional: roentgen
SI: coulomb/ Kg of air

25
Q

Units for absorbed dose

A

traditional: rad
SI: Gray

26
Q

Unit for dose equivalent

** Quality Factor**

A

traditional: rem
SI: sievert

27
Q

Unit for activity
brachytherapy
1 disintegration/sec

A

traditional: curie
SI: bequerel

28
Q

1 roentgen= ? Coulomb/Kg of air

A

2.58x10^-4

29
Q

quality factor of:

x-rays, gamma rays, and electrons

A

1

30
Q

quality factor of:

thermal neutrons

A

5

31
Q

quality factor of:

neutrons, heavy particles

A

20

32
Q

Types of measurement devices:

A
  • gas filled detectors
  • TLD
  • Film
  • Pocket ionization chambers
  • neutron detectors
33
Q

types of gas filled detectors

-calibrated within 2%

A
  • ionization chamber (pocket dosimeter)

- geiger muller detector (very sensitive, measures presence of radiation)

34
Q

TLD

A
thermoluminescent dosimeter
lithium fluoride, dose can be stored for days
anneling process
1 hour: 400 degree C
24 hours: 80 degree C
35
Q

pocket ionization chambers

A

immediate readout
initially expensive
for infrequently exposed
has to be charged to zero it out

36
Q

neutron detectors

A

“rascal”
BF3 or Argon
bubble counters

37
Q

OSL

A

optically stimulated
light in relation to dose
Al2 O3

38
Q

rascal neutron detector

boriated polyethylene

A

above 10

our range 6-20

39
Q

Regulatory Agencies:

National Council on Radiation Protection and Measurement

A

NCRP

set exposure levels

40
Q

Regulatory Agencies:

International Commission on Radiation Protection

A

ICRP

set exposure levels

41
Q

Regulatory Agencies:

Nuclear Regulatory Commission

A

NRC

isotope usage

42
Q

Regulatory Agencies:

Food and Drug administration

A

FDA

linac license

43
Q

Regulatory Agencies:

Department of Transportation

A

DOT

Transporting isotopes

44
Q

Non stochastic effects

deterministic

A

threshold

45
Q

stochastic

A

non threshold

46
Q

dose response curves

linear and quadratic

A

probability increases with dose, not sensitivity

47
Q

Somatic effects

A

in exposed individual

carcinogenesis

48
Q

genetic effects

A

occurring in future children

mutagenesis

49
Q

developmental effects

A

develop while in eutero
teratogenesis
embryologic

50
Q

ALARA

A

as low as reasonably achievable

51
Q

comparable risk

A

it shouldn’t be more dangerous to work in our field than any other

52
Q

genetically significant dose

A

GSD take into account all radiation types

measurement of genetic rise to an entire population

53
Q

3 major rules of radiation

A
  1. time
  2. distance
  3. shielding
54
Q

In cobalt machines, exposure must be less than ____ at any point ___ m from the source

A

10 mR/ hour

1 m

55
Q

if average radiation reads ___ then it is outside the range of reading

A

2 mR/ hr

56
Q

What are the shielding factors?

B=pd^2/WUT

A
w- workload
u-use factor
t- occupancy factor
d- distance
b- transmission factor
p- point of interest dose
57
Q

Safety equipment

examples of quality assurance testing

A
  • warning signs
  • warning lights
  • door interlocks
  • visual and aural communication (should be able to see and hear pt)
  • beam on monitors
  • emergency off controls (if not working, go straight to circuit breaker)
  • QA
58
Q

Brachytherapy

A
  • must have license from NRC
  • keep a log of sources in/out
  • use shielded carriers
  • post patient room
  • personnel monitor
  • warning signs and survey
  • leak tests
  • HDR (High Dose Rate)
59
Q

Inventory:
removing
returning

A

removing- take inventory
sources removed, sources remaining
returning- sources remaining, complete inventory

60
Q

administrative requirements and roles

A
ALARA
RSO- implement radiation protection program
RSC- oversee the use of the material
written procedure- 
written directive- prescription
61
Q

Medical event:

A

recordable event
misadministration
180-200 cGy per fraction

62
Q

Disposal of radioactive waste

A
  • facility dependent
  • usually separated by half life
  • must decay 10 half lives
  • can be in different forms
  • ** All falls under NRC**