di bilik konferens jpd htjs

1. RADIAT
ION
P
ROT CT
E ION IN
DIAGNOST radiology
IC
NURAIN BORHAN
PEGAWAI SAINS (FIZIK)
17 OCTOBER 2013
Page 1

2. CONTENT
Protection to The Public
Source of Radiation Dose to Personnel
Dose Reduction Methods and Techniques
Protection in Mobile X-ray Radiography
Personnel Protective Equipments
Personnel Dose Monitoring
Dose Limits
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3. PROTECTION TO THE PUBLIC
Concern on the x-ray room design
that includes:
1. X-ray room wall and shielding
2. Lead lined door
3. Interlock system
4. Warning sign
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4. X-RAY ROOMS
X-Ray Room Wall
Lead (Pb) is widely used for shielding because
of its high atomic number (Z=82)
Lead is costly. Materials with lead equivalent
property are introduced to substitute lead at
lower cost.
The common lead equivalent materials used
for shielding in diagnostic radiology are barium
gypsum and concrete.
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5. X-RAY ROOMS
Lead Lined Door
• The doors of x-ray rooms should
be lead lined with no radiation
leakage around the edges.
• lead-lined rebates or lead baffles
where appropriate, depending on
whether the door design is
hinged or sliding.
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6. X-RAY ROOMS
Room Interlock System
1. Prevent exposure
unit from before the
door is closed.
2. Turn off the x-ray
beam immediately
when the entrance
door is open.
Page 6

7. X-RAY ROOMS
Warning Sign
 Displayed on each door to
discourage the entry of nonauthorized persons.
 Written in national language and
can be understand by the
personnel and member of the
public.
 The doors should always be
closed during exposure.
 Red light to signify when the xrays are on.
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8. SOURCE OF RADIATION DOSE TO PERSONNEL
3 categories of radiation sources that
contribute dose to the personnel:
i. Primary radiation source
ii. Scattered radiation source
iii. Leakage radiation source
The scattered and leakage radiation
sources are collectively known as
secondary radiation source.
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9. Page 9

10. SOURCE OF RADIATION DOSE TO PERSONNEL
Leakage Radiation Source



x-ray that does not exit from
the collimator opening but
penetrates through protective
tube housing.
Always present whenever xray is produced.
Contributing dose to personnel
and background radiation
within the x-ray room.
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11. Page 11

12. DOSE REDUCTION METHODS & TECHNIQUES
The patient become the source for
scattered radiation.
Scatter however also obeys the ± the
Inverse Square Law, so distance from the
patient improves safety
I1/I2 = D22/D12
Protective lead aprons and shielded barriers
protect personnel from secondary radiation.
In case of fluoroscopy, the time of exposure
should be kept as low as possible.
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13. DOSE REDUCTION METHODS & TECHNIQUES
Proper beam collimation will reduce offaxis Precisely only at the region of
diagnostically interested.
A high-speed image receptor systems
such as film-cassette combination and
intensifying screen.
Repeat radiograph should be avoided or
minimized through effective communication
and correct radiographic techniques.
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14. EXAMPLES OF REJECT FILMS
Page 14

15. PROTECTION IN MOBILE X-RAY RADIOGRAPHY
Mobile radiography is conducted usually in
ward with no specific protection to the
surrounding.
Lead apron, gloves and thyroid shields should
be worn whenever the mobile protective
barrier is unavailable.
Remote control exposure device. The cord
should permit the radiographer to stand at
least 2m from the patient.
.
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16. PERSONNEL PROTECTIVE EQUIPMENTS
Personnel Protective Equipments
(PPE) should be worn by personnel
whenever he/she cannot remain
behind the protective barrier
during exposure.
Lead apron
Thyroid shield
Lead eyeglass
Lead gloves
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17. PERSONNEL PROTECTIVE
EQUIPMENTS
Page 17

18. Page 18

19. PERSONNEL DOSE MONITORING
Film Badges
•Advantages
Permanent exposure record
Good accuracy at higher exposures
•Limitations
Exposure not read immediately
Sensitivity to heat
Less accuracy at lower exposures
The minimum recording level adopted for the film badge
dosemeter is 0.10 mSv and all doses less than 0.10 mSv are
reported as being below the recording level.
Page 19

20. Do not
forget to
change
your film
badge
every
month
before 5th
Page 20

21. DOSE LIMITS
Whole Body
Exposure Dose
Limit (mSv/year)
1
Public
Radiation Workers
20*
Fetus
1
Apprentices and
students
6
* The maximum effective dose on the
worker averaged over a period of 5
consecutive years shall not exceed
20mSv
Page 21

22. Dose limits do not apply to
medical exposures and
natural background radiation
But, that does not mean that
radiation dose to
patient should be ignored!
Page 22

23. Optimization
Trade-offs
between
radiation dose
and
image quality
Page 23

24. Page 24

25. CONCLUSION
The ultimate goal of radiation
protection is optimising radiation
exposures to levels consistent with
the needs and
benefits of humanity and
compatible with the other hazards
to which man is exposed
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