Chapter 4 - RADIATION QUANTITIES & UNITS

Question 1

Who discovered x-ray and when?

Answer 1

Wilhelm Conrad Roentgen
November 8, 1895

Question 2

Who was the first reported fatality due to radiation induced cancer? & when ?

Answer 2

Clarence Dally
- assisted Thomas Edison

1904

Question 3

Types of occupational exposure injuries and early radiation injuries

Answer 3

somatic
-radiodermatitis- tissue necrosis, lesions, redness
-blood disorders-apastic anemia, results from loss of bone marrow , leukemia,

Question 4

Early unit for measuring radiation exposure, range of years it was used, and why it was replaced

Answer 4

skin erythema dose
1900-1930
it was inaccurate - differs per individual- and a dose producing visual skin evidence indicates a high exposure level.

Question 5

In what year did the second International Congress of Radiology meet in Sweeden, and what was decided?

Answer 5

1928
Roentgen (R) was accepted as a unit of exposure, but not adequately defined

• ICRU was charged to define

Question 6

What was the concept of tolerance dose and what was it later replaced by?

Answer 6

a way to focus on minimizing risk in the 1930’s
- later replaced with MPD (Maximum Permissible Dose) in the 1950’s

Question 7

Early Tissue Reactions

Answer 7

early tissue effects withing minutes/ hours/ days/ weeks

-nausea
-fatigue
-skin redness
-loss of hair
-fever
-blood disorders

Question 8

Late Tissue Reactions

Answer 8

Months or years after exposure
- cataracts, fibrosis, organ atrophy, reduced fertility, sterility

Question 9

Stochastic Effects

Answer 9

cancer, genetics (hereditary)

Question 10

In what year was Roentgen internationally accepted as the unit of measurement for exposure to x radiation and gamma radiation?

Answer 10

1937

Question 11

Maximum permissible dose

Answer 11

MPD
1950’s
- no dose is safe-

Question 12

Exposure
SI unit:
traditional unit:

Answer 12

(X)
amount of radiation responsible for ionization of air
-intensity of radiation to a specific area (skin surface)
measures equipment output
SI unit: C/kg
traditional unit: Roentgen

Question 13

Air Kerma

Answer 13

“kinetic energy released per unit mass”
SI quantity used to express how energy is transferred from BEAM of radiation to material SKIN.
entrance dose
Gy /

Question 14

Absorbed Dose
SI unit:
traditional unit:

Answer 14

(D)
amount of energy per mass unit absorbed by an irradiated object
** patient dose
SI unit: Gy
traditional unit: Rad
1Gy= 100 Rad

Question 15

Quality Factor

Answer 15

dose equivalence takes into account varied biologic impact by using a specific modifying factor

Question 16

LET

Answer 16

Linear Energy Transfer

amount of energy transferred on average by incident radiation to an object per unit length of a track through an object

• helps explain need for quality factor
  -how deeply penetrating radiation is to tissue

Question 17

Equivalent dose
SI unit:
traditional unit:

Answer 17

EqD = D x Wt

average absorbed dose in tissue or organ
**radiation worker dose

SI unit: Sv
traditional unit: Rem

Question 18

Effective dose
SI unit:
traditional unit:

Answer 18

EfD = D x Wr x Wt
overall risk of exposure

SI unit: Sv
traditional unit: Rem

Question 19

Collective Effective Dose
SI unit:
traditional unit:

Answer 19

ColEfD
describes radiation exposure of a population or group from low doses of different sources of ionizing radiation - internal & external

SI unit: person - sievert
traditional unit: man-rem

Question 20

TEDE

Answer 20

Total Effective Dose Equivalent
a radiation dosimetry quantity that was defined by the NRC to monitor and control human exposure to ionizing radiation

measured annually - 0.05Sv
(general population 0.001 Sv)