radiation-protec tion.ppt

sf

2. RadiationRadiation

RadiationRadiation: Energy in : Energy in
the form of particles or the form of particles or
electromagnetic waveselectromagnetic waves

Ionizing RadiationIonizing Radiation: :
Radiation with Radiation with
sufficient energy to sufficient energy to
remove an electron remove an electron
from an atom or from an atom or
moleculemolecule..

3. RadioactivityRadioactivity

The process by which The process by which
unstable atoms unstable atoms
spontaneously spontaneously
transform to new transform to new
atoms* and in the atoms* and in the
process emit process emit
radiationradiation..
$
-
* The “new atom” may be the
same atom in a lower energy
state.

4. External Exposure / External Exposure /
IrradiationIrradiation

External irradiation External irradiation
occurs when all or part occurs when all or part
of the body is exposed of the body is exposed
to penetrating to penetrating
radiation from an radiation from an
external source. external source.

During exposure, some During exposure, some
of this radiation is of this radiation is
absorbed by the body absorbed by the body
and some passes and some passes
completely through. completely through.

Following external Following external
exposure, an individual exposure, an individual
is not radioactive.is not radioactive.
s




Local
Partial
Body
Whole
Body


5. Protection from External Protection from External
RadiationRadiation

Time – less time, less dose.Time – less time, less dose.

Distance – more distance, less Distance – more distance, less
dose.dose.

Shielding – more shielding, Shielding – more shielding,
less dose. less dose.

6. Internal ExposureInternal Exposure

Internal exposure is from Internal exposure is from
radioactive materials that radioactive materials that
have been taken into the have been taken into the
body. body.

Radioactive material can Radioactive material can
enter the body through: enter the body through:

InjectionInjection

InhalationInhalation

IngestionIngestion

AbsorptionAbsorption

Once radioactive materials Once radioactive materials
are in the body, they are in the body, they
irradiate body tissues as long irradiate body tissues as long
as they remain in the bodyas they remain in the body
Thyroid
Lung
Liver
Bone

7. Internal ExposureInternal Exposure
•There are two ways for radioactive materials to be There are two ways for radioactive materials to be
removed from the body:removed from the body:

Biological clearance Biological clearance

Radiological decayRadiological decay
•The term “committed dose” refers to the fact that the The term “committed dose” refers to the fact that the
radioactive dose will continue as long as the radioactive dose will continue as long as the
radioactive material is in the bodyradioactive material is in the body
•The amount of radioactivity in the body can be The amount of radioactivity in the body can be
assessed by Bioassay;(measurement of the assessed by Bioassay;(measurement of the
concentration or potency of a substance by its effect concentration or potency of a substance by its effect
on living cells or tissues)on living cells or tissues)

10. -measured in C/kg or
Roentgen(R)
-amount of charge (electrons)
liberated per kilogram of Air
(Ionization)
1R = 2.58x10
-4
C/Kg
C- curie

11. -measured in Gray (Gy) or
Rad
-amount of energy
deposited/ absorbed per
kilogram of tissue
1Gy = 1 Joule/Kg
100 Rad = 1 Joule/Kg
1Rad = 1/100 Gy

12. - measured in Sieverts (Sv) or
Rem
- amount of biological damage
- gives a measure dose as if
received by the whole body
- used to equate dose to risk
1Sv = 1 Joule/Kg
100 Rem= 1 Joule/Kg
1Sv = 1/100 Rem

16. 
More radiosensitive than adults due to sensitive cells More radiosensitive than adults due to sensitive cells
and developing organsand developing organs

Gonad shielding importantGonad shielding important

Radiographic examinations difficult:Radiographic examinations difficult:

Patient movementPatient movement

Exposure technique more critical Exposure technique more critical

Embryo/fetus is rapidly developing so is more sensitive to a Embryo/fetus is rapidly developing so is more sensitive to a
possible radiation effect than an adult.possible radiation effect than an adult.

Effects vary with amount of radiation and stage of development Effects vary with amount of radiation and stage of development
of the embryo/fetus.of the embryo/fetus.

Principal effects are loss of pregnancy, malformations, and Principal effects are loss of pregnancy, malformations, and
mental retardation.mental retardation.

18. Dose Units & Radiation Safety 18
Somatic EffectsSomatic Effects
Damages to cell membranes, mitochondria and cell nuclei result in abnormal cell functions,
affecting their division, growth and general heath.
Organs such as skin, lining of gastrointestinal tract, embryos, and bone marrow, whose cells
proliferate rapidly are easily damaged.
Bone marrow makes blood, and its damage leads to reduction of blood cell counts and
anemia.
Damage to germinal tissues reduces cell division, and induces sterility.

19. 
Genetic mutations occur from incorrect Genetic mutations occur from incorrect
repair of damaged chromosomes in egg or repair of damaged chromosomes in egg or
sperm cells.sperm cells.

Ovaries can repair mild radiation damage.Ovaries can repair mild radiation damage.

Genetic mutations may show up in future Genetic mutations may show up in future
generations.generations.

Radiation-caused genetic mutations have Radiation-caused genetic mutations have
been shown in animal studies at very high been shown in animal studies at very high
radiation doses (>25 rem).radiation doses (>25 rem).
Genetic EffectsGenetic Effects

20. 
cancer

birth defects

genetic effects

21. Photograph of the patient’s
back 6-8 weeks after multiple coronary
angiography and angioplasty procedures.
Photograph of the injury 16-21 weeks after
the procedures. A small ulcerated area is
present.

22. Close-up of the lesion shown in C
Photograph of the patient’s back 18-21 months
after the procedures. Tissue necrosis is evident

23. Photograph of the patient’s
back after Grafting.

25. Summary of Biological Effects of Summary of Biological Effects of
RadiationRadiation

Radiation may…Radiation may…

Deposit Energy in BodyDeposit Energy in Body

Cause DNA DamageCause DNA Damage

Create Ionizations in Body, Leading to Free Create Ionizations in Body, Leading to Free
RadicalsRadicals

Which may lead to biological damageWhich may lead to biological damage

26. Response to radiation depends Response to radiation depends
onon::

Total doseTotal dose

Dose rateDose rate

Radiation qualityRadiation quality

Stage of development at the time of Stage of development at the time of
exposureexposure

27. Radiation exposure of personnelRadiation exposure of personnel
and the general public should be keptand the general public should be kept
As Low As Reasonably Achievable.
A.L.A.R.A. policyA.L.A.R.A. policy
RADIATION RADIATION
PROTECTIONPROTECTION

28. correct exposure factors
correct radiographic technique
appropriate radiation protection
appropriate development/viewing techniques
appropriate radiographic positions for
examination
minimize repeat examinations
continuing education

29. Only a physician or a registeredOnly a physician or a registered
x-ray technologist under the x-ray technologist under the
directdirect
supervision of a physician may supervision of a physician may
perform fluoroscopy.perform fluoroscopy.

30. 
TimeTime

DistanceDistance

ShieldingShielding

Contamination Contamination
ControlControl
4 Basic Categories

31.  Reduce of your exposure
 Increase from the source
 Make use of available
TIMETIME
DISTANCEDISTANCE
SHIELDINGSHIELDING

32. 
minimize time in radiography or fluoroscopy roomsminimize time in radiography or fluoroscopy rooms

minimize time spent with patients who are undergoing minimize time spent with patients who are undergoing
therapy treatment eg. nuclear medicine procedures, therapy treatment eg. nuclear medicine procedures,
radioactive implants radioactive implants

Know Your ProtocolKnow Your Protocol

Read the procedure through carefullyRead the procedure through carefully

Understand the steps clearly orUnderstand the steps clearly or

Have the protocol displayed where you can Have the protocol displayed where you can
see itsee it

Practice the technique beforehandPractice the technique beforehand

33. TimeTime

Radiation is only produced Radiation is only produced
when the beam is on!when the beam is on!

Irradiate only when it is Irradiate only when it is
necessary to observe motion.necessary to observe motion.

Last-image-hold and instant Last-image-hold and instant
replay can usually save dose.replay can usually save dose.

34. The distance between you and the isotope is of
paramount importance for high energy emitters and
penetrating radiations.
The intensity of radiation at different distances is
represented by the formula: law stating that a specified
physical quantity or intensity is inversely proportional to the
square of the distance from the source of that physical quantity.

This is the Inverse Square Law.
I
2
d
1
d
2
I
1
()=
2

36. 
Inverse Square Law - double the Inverse Square Law - double the distance distance
from the source of from the source of radiation - radiation - reduce dose by a reduce dose by a
factor of 4factor of 4

General rule - 3 meters General rule - 3 meters (approximately (approximately
10 ft) from the source 10 ft) from the source of radiation - dose is of radiation - dose is
insignificantinsignificant

Keep the x-ray source (the tube) as far away from Keep the x-ray source (the tube) as far away from
you (the operator) as possible consistent with you (the operator) as possible consistent with
optimal imagingoptimal imaging

37. Radiation Safety PrincipleRadiation Safety Principle

Use the least amount of magnification Use the least amount of magnification
consistent with seeing the object consistent with seeing the object
adequately.adequately.

BIGGER IS NOT ALWAYS BETTER!!BIGGER IS NOT ALWAYS BETTER!!

A larger image means more radiationA larger image means more radiation

If it is necessary for adequate visualization, If it is necessary for adequate visualization,
finefine

If it does not improve procedure safety or If it does not improve procedure safety or
performance, reduce the magnificationperformance, reduce the magnification

38. Fluoro only when viewing monitor
Use pulsed fluoroscopy when possible
Use last image hold

39. Personal shieldingPersonal shielding
 lead aprons - at least 3 - 5mm Pb lead aprons - at least 3 - 5mm Pb
equivalent provide up to 90% equivalent provide up to 90%
shielding.shielding.
 thyroid / eye shielding during thyroid / eye shielding during
fluoroscopyfluoroscopy
 lead glove (5mm + Pb eq.) if hands lead glove (5mm + Pb eq.) if hands
are are likely to be in the beamlikely to be in the beam
 Lead drape on fluoro tower provides Lead drape on fluoro tower provides
an additional 90% protection of the an additional 90% protection of the
remaining remaining 10% from lead aprons 10% from lead aprons
above.above.

40. Protective barriersProtective barriers

lead glass / acrylic for windows, lead sheets lead glass / acrylic for windows, lead sheets
in doors or plaster board walls, brick wallsin doors or plaster board walls, brick walls

minimize directing primary beam at minimize directing primary beam at
widows / doorswidows / doors

best position to be located during x-ray best position to be located during x-ray
exposureexposure

41.  State law requires that, during
fluoroscopy, one badge must be
worn outside the apron at the
collar level.
Some institutions provide
additional badges, usually upon
request during pregnancy

43. Badge readings are
reviewed regularly by the RSO
Institutional investigation
levels are set belowregulatory
limits
Personnel are notified
regularly and badge readings are
posted

45. QuestionsQuestions

How much radiation does it take to How much radiation does it take to
cause a person’s cause a person’s risk for a for a
health effect to increase? to increase?

What are the health effects that can What are the health effects that can
occur if there is enough exposure?occur if there is enough exposure?

Is there a level of radiation that is Is there a level of radiation that is
safe??

46. RiskRisk

Risk from a radiation dose is typically based on Risk from a radiation dose is typically based on
calculations of the “real” effect of the radiation calculations of the “real” effect of the radiation
dose that is absorbed.dose that is absorbed.

These calculations are based onThese calculations are based on: :

The type of radiation.The type of radiation.

Each type of radiation is different and affects tissues differently.Each type of radiation is different and affects tissues differently.

The energy that it leaves in the body.The energy that it leaves in the body.

More energy means a higher probability of an effect.More energy means a higher probability of an effect.

Where in the body the energy remains.Where in the body the energy remains.

Radiation exposure to a nonsensitive area of the body (i.e., wrist) Radiation exposure to a nonsensitive area of the body (i.e., wrist)
really has no actual effect. Radiation exposure to a sensitive area really has no actual effect. Radiation exposure to a sensitive area
of the body (i.e., blood-forming organs) can have an effect if the of the body (i.e., blood-forming organs) can have an effect if the
amount of energy left is high enough.amount of energy left is high enough.