1

WEEK 7RADIATION BIOLOGY &

PROTECTION Part 1

FINAL

2

3

Sources of Ionizing Radiation

1. ___________ Radiation

2. ___________Radiation

4

Electromagnetic Spectrum –shows ranges in intensity

5

Background Radiation has been around a long time….

6

7

Radon & Uranium most common sources

8

AVE population exposure= 20 – 30 mrem/year

1. In some places in United States average ________mrem/yr Majority due to _________ gas  

2. Many places on earth receive more than _________ mrem/yr

from radon

9

MEDICAL IMAGING

1. __________________x-rays2. _________________ x-rays

Greatest source of ________ ________radiation

10

11

What is the difference between x-rays and gamma rays????

1. Their______________________

2. X-rays are _______ __________

3. Gamma comes from the ______ of the atom

12

Terminology to cover

1. Units of Measurement

2. ALARA

3. DOSE –1. Cumulative2. Annual

4. Target theory

5. Direct vs. Indirect Hit

6. Somatic vs. genetic

13

UNITS OF RADIATION MEASUREMENT

1. To ______________the amount of radiation

A: Received by _________________ _________________ _________________

14

Conventional vs. SI units

1. British units used since 1920’s

2. United States still uses this system

1. New system developed in 1948

2. System of Units based on Metric measurements developed by International Committee for Weights and Measures

3. 1985- officially adopted

15

Conv. Units SI Units

1. RADS

2. REMS

3. R - ROENTGEN

1. _______

2. _______

3. _______

Not equal in amount

16

Comparsion of Units

17

R - ROENTGENS

RADS –

PATIENT DOSE

REMS

OCCUPATIONAL EXPOSURE

18

Conventional Unit of ROENTGEN (R)

1. SI unit =__________

2. The quantity of radiation exposure in_______________

3. Measures __________of the x-ray tube

4. Does not indicate the actual ________________________________

19

RADIATION ABSORBED DOSE (RAD) SI = GRAY (Gy)

1. Measures the _____________ of energy ___________ by any medium (__________)

2. 1 Gray (Gy) = 100 _______

3. 1/100 Gy = 1 _______

20

RAD to GRAY

1. 100 rad = 1 Gy =1000 mGy

1/100 Gy = 1 rad

2. 10 rad = .1 Gy = = 100 mGy

3. 1000 mRad = 1 rad = .01 Gy = 10 mGy

21

Radiation Equivalent Man

Used for ________

Traditional Unit = _________

SI Unit = ____________ (Sv)

1 Sv = 100 __________

1/100 Sv =1 _________

22

RADIATION EQUIVALENT MAN(REMS) SI UNITS = SIEVERT

1. Different _________ of radiation produce different responses

2. The unit of dose ___________, expressed as

__________________________________

3. Used for ____________(employee) exposures

4. Can be used when for dose of patient

23

QUALITY FACTOR

Qualifies what the damage is from different types of radiation

Example: QF for X-ray is 1 QF for alpha is 20

Alpha is 20 x more damaging to tissue

24

Rad VS. Rem

1. QF of x-ray is 1

2. 1 RAD X QF = 1 REM

3. 1 GRAY X QF = 1 SIEVERT

25

26

27

Why did the bunny die??

BUNNY A

Received 200 rads

BUNNY B

Received 200 rads

28

Why did the bunny die??

BUNNY A 200 rads x 1 for X-RAY = 200 RADS

BUNNY B200 rads x 20 for

alpha = 4000 rads

29

REM to Sievert

1. 100 rem = 1 sV =1000 msv

1. 10 rem = .1 sV = = 100 msv

2. 1000 mRem = 1 rem = .01 sV = 10 msv

30

RADS REMS RADS

GRAYS

Patient absorbed dose

REMS

SIEVERTS

Employee(technologists)

=

31

Cell Response to Radiation

32

Response of cells to radiation

Cell sensitivity is dependant on:

1. Type of cell

2. Type of damage received

3. Type of radiation exposed to

33

Sensitivity to radiation based on sex

34

Which (Male or Female) GONADs are external vs internal?

35

Which gender has gonads from birth?

36

Which gender constantly produces new reproductive cells?

37

Which GENDER is more sensitive to radiation at birth? Why?

38

Dose limits

39

Permissible Occupational Dose

Annual dose :1. 5 Rem/year 50mSv/year2. (5000 mrem)

Cumulative Dose1. 1 rem x age 10mSv x age

40

Allowable DOSE - ANNUAL BRITISH UNIT

5 REMS

SI UNIT

5O mSv

41

OCCUPATIONAL EXPOSURES

1. 5 REMS / YEAR

2. BUT NOT TO EXCEED 1.25 REM/QUARTER

42

Allowable DOSE – TOTALCUMMULATIVE

BRITISH UNIT

Age x 1 rem

Old MPD dose 5(age-18)

SI UNIT

Age x 10msv

43

44

Declared Pregnant Worker

1. ____ badges provided1. 1 worn at collar (___________________exposure)2. 1 worn inside apron at waist level (____ exposure)

2. Under 5 rem – _____________________ risk3. Risk _____________________ above 15 rem4. Recommend ________ (spontaneous) 25 rem

5. (“Baby exposure” approx 1/1000 of ESE)

www.ntc.gov/NRC/RG/08/08-013.html

45

Pregnancy & Embryo

1. Mother __________worker (5 rem)

2. Baby 500_______.5 rem/ year .05 rem/____________ 5______ .5 mSv / ________

46

47

Fetus Exposure

1. Radiation exposure is most harmful during the __________ trimester of pregnancy

2. ______________ Exposure limit 0.05 rem or 0.5 mSv PER MONTH 0.5 rem or 5 mSv total gestation

48

49

Education and Training Exposures

Student’s must never hold patients during exposures

Effective dose limit (Annual) 0.1 rem or 1 mSv (1/50 of Technologist’s dose)

50

PUBLIC EXPOSURE NON MEDICAL EXPOSURE

10 % of Occupational exposure 0.5 rad or 500 mrad or 50mgray

Under age 18 and Students 0.1 rem 10 mrem 1mSv

51

Review

52

Radiation Monitoring

53

Radiation Monitoring

1. Monitors measure the quantity of radiation received.

2. Any radiation worker must be monitored

3. to determine estimated dose exposure

54

Personnel Monitoring Devices

1. Film Badges

2. Thermoluminescent Dosimeters (TLD)

3. Pocket Dosimeters

4. Optically Stimulated Luminescence (OSL Dosimeters)

55

TLD

56

Film Badges – changed monthly

57

POSL

58

59

Field Survey Instruments

Geiger Muller counter

• “Cutie Pie”

Ionization Chamber

60

Q = t x ּת

CUTIE PIE

61

Review

What is the annual allowable dose for a 32 year old Technologist?

62

What is the cummulative allowable dose for a 32 year old Technologist?

63

64

Regulatory Agencies

1. NCRP – National Council on Radiation

Protection

2. NRC – Nuclear Regulatory Committee

65

REGULATORY AGENCIES

1. NCRP - Reviews recommendation for radiation protection & safety.

Distributes information re: radiation awareness

2. NRC Makes LAWS & enforces regulations

66

QUESTIONS ?