Introduction to Radiologic and Imaging Sciences and Patient Care: Basic Radiation Protection and Radiobiology Flashcards


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1

Results in ionization of atoms.

Loss of electrons

2

___________ must outweigh the ________ of any x-ray diagnostic study.

Benefits risks

3

Two sources of ionizing radiation

natural and manmade

4

_____________ and __________ x-ray examinations make up the largest portion of human-made radiation exposure.

Medical and dental

5

Conditions necessary for x-ray production.

Source of electrons (Cathode filament)(negative) Means of accelerating electrons/high-speed motion (Voltage) Mechanism stopping electrons abruptly/deceleration (Target/Anode)(positive)

6

Energy of beam is expressed in __________.

Kiloelectron volts (keV)

7

Three possible paths an x-ray beam can undergo.

Total absorption Pass through with no energy loss Scattering/secondary interaction with loss of energy

8

Five types of x-ray interactions with matter.

Classic coherent scattering Photoelectric interactions Compton scattering Pair production Photodisintegration

9

Who does photoelectric interactions expose?

Patient

10

Who does compton scattering expose?

Radiographer/Tech

11

Involves very-low energy x-rays. No ionization occurs.

Classic Coherent Scattering (Thompson scattering)

12

What does coherent scattering do to an atom?

Atom becomes excited and emits x-ray with same energy.

13

Classic Coherent Scattering occurs when x-rays possess energy levels below what keV?

10 keV

14

Occurs within the diagnostic x-ray energy range

Photoelectric effect Compton scattering

15

Incoming x-ray photon is completely absorbed by collision with inner-shell(k-shell) electron.

Photoelectric effect

16

What does Photoelectric effect do to an atom?

-Electron (photoelectron) leaves atom, creating an ion pair. -Free electron eventually unites with other matter. -Secondary radiations created as a result of electron cascade from outer shells to inner shells.

17

In the Photoelectric effect, which electron produces an x-ray with energy high enough to impact your image?

The electron that drops in to the hole in the k-shell

18

Radiation interaction responsible for most hazard to patients. Why?

Photoelectric effect Because there is complete absorption in the patient

19

Incoming photon collides with outershell electron

Compton Scattering

20

What does Compton Scattering do to an atom?

-Incoming photon collides with outershell electron, creating a free Compton electron (recoil) and an ion pair. -Incoming photon loses some of its energy through collision, scatters off in a random direction (scatter angle), and undergoes other interactions until its energy is gone. -The electron vacancy is filled nearly instantly.

21

Reaction with matter that requires very high energy photons.

Pair Production

22

For the pair production to occur, the energy of the incoming x-ray photon must be at least:

1.02 MeV

23

What does Pair Production do to an atom?

-The incoming photon interacts with the force field around the nucleus then disappears. -Two particles reappear, each with equal energy (0.51 mEv). -The positron collides with a free electron and creates an annihilation reaction. -Annihilation reaction creates two photons at opposites angles to each other.

24

Reaction with matter that requires the energy of the photon to be extremely high.

Photodisintegration

25

What does Photodisintegration do to an atom?

-Incoming photon interacts with nucleus of atom, creating nuclear instability. -Nuclear fragment is given off as nucleus seeks stability

26

Common interaction in the nuclear industry

Photodisintegration

27

Measures exposure in air and is not used to express absorbed dose to individuals. A measure of ionization in air as a result of exposure to x-rays or gamma rays

Roentgen (Coulombs per Kilogram)

28

Measures the amount of energy absorbed in any medium, defined as 100 ergs of energy absorbed in 1 g of absorbing material

Radiation absorbed dose(rad) (Gray)

29

___ Gy = _____ rad

1 Gy = 100 rad

30

Unit of dose equivalence. Accounts for different types of radiation and their biologic effects

Radiation equivalent man (rem) (Sievert)

31

formula for rem

rem = rad × QF(quality factor)

32

Used to measure energy transferred from radiation to a material

Air Kerma

33

What is KERMA?

"kinetic energy released in matter"

34

Measures the activity of a radioactive material (radionuclide) Used in nuclear medicine and radiation therapy

Curie (Becquerel)

35

What is curie equal to?

1 Ci = 3.7 × 10^10Bq

36

Who regulates the Standards of Exposure?

FDA and its Center for Devices and Radiological Health (CDRH).

37

ALARA

As Low As Reasonably Achievable

38

Dose equivalent for radiation workers is based on radiation received from what source?

Occupational exposure

39

The annual whole-body effective dose limit for the occupational worker is ____ mSv (____ rem).

50 mSv (5 rem)

40

Two major parts of a cell.

Nucleus Cytoplasm

41

____% of cell content is water

80%

42

Two classes of human cells.

Somatic (any cell that is not a genetic cell) Genetic (will affect future generations)

43

Perform all the body's functions

Somatic Cells

44

How many chromosomes does a somatic cell posses?

46 (23 pairs)

45

Reproductive cells of an organism. Very radiosensitive.

Germ cells

46

How many chromosomes does a germ cell possess?

23

47

Two theories of cellular irradiation damage exist.

Direct-hit theory Indirect-hit theory

48

According to the law of Bergonie and Tribondeau, cells are more radiosensitive if they are __________.

Highly mitotic Primitive in structure

49

Cells are most sensitive to radiation during __________.

Active division (More immature/rapidly dividing)

50

Results of radiation to a cell

Cellular death Delayed mitosis Altered mitotic rate

51

Acute radiation syndrome stages. Requires large amounts of total body exposure.

Prodromal stage Latent period Manifest stage Recovery or death

52

Radiation Syndromes

Bone marrow syndrome Gastrointestinal syndrome Central nervous system syndrome -Results in eventual death.

53

Cardinal rules of protection of patient.

Time (lowest possible) Distance Shielding

54

Three popular monitoring technologies

Pocket dosimeter Optically stimulated luminescence dosimeter(OSL) Thermoluminescent dosimeter (TLD)

55

Personal radiation monitor that will provide a near immediate reading of radiation exposure.

Pocket dosimeter

56

Occupational Personnel Monitoring Rules

Worn at the collar level Worn outside of lead apron Device should face forward. Pregnant radiographers may have a second device worn at waist level and under the lead apron

57

Monthly equivalent dose to fetus should not exceed _____mSv (____ rem)

0.5 mSv (0.05 rem)