1. Ionizing
radiation...Effects
and Safety
what every physician must know
Dr/Ahmed bahnassy
Consultant radiologist
PSMMC

3. Aims of lecture
• To become familiar
with the mechanisms
& biological effects
following exposure to
ionizing radiation.
• To be aware of the
risks of ionizing
radiation .
• To know main safety
issues of protection.

4. RADIATION:-
Radiation is the energy that comes from a source and
travels through some material or space as waves or
photons.
IONIZING RATIATION:-
This kind of radiation on interaction with matter produce
charged particles called ions.
This type of radiation has enough energy to break
chemical bonds.
NON-IONIZING RATIATION:-
Radiation that does not have enough energy to break
chemical bonds but can vibrate atom. It cannot produce
ions.

5. SOURCES OF RADIATION

7. UNITS OF RADIATION:-
1) Roentgen (R):- Radiaton exposure in a volume of air.
2) Rad:-
It is the unit of absorbed dose.
The SI unit of absorbed dose is Gray (Gy)
1 Gy=100 rad
3) Rem:-
It is the unit of effective dose.
Used only in radiation protection.
The SI unit is Sievert
1 Sv= 100 rem
1 mSv = 0.001 Sv.

8. 0.01 mSv
0.5 Chest
X-ray.
0.02mSv
1 CXR
0.07 mSv
3.5 CXR
1.3mSv
65 CXR
0.7mSv 1.0mSv 2.5mSv 3.0mSv 7.0mSv
35 CXR 50 CXR 125CXR 150CXR 350CXR

9. 2.3mSv 8.0mSv 10mSv
115 Chest 400 CXR 500 CXR
X-rays.

10. 15 mSv
750 CXR
4 mSv
200 CXR
6 mSv
300 CXR

11. THYROID SCAN RENAL SCAN LUNG PERFUSION
1.0 mSv 1.0 mSv 1.0 mSv
50 CXR 50 CXR 50 CXR
BONE SCAN PET HEAD (FDG) CARDIAC GATED
4.0 mSv 5.0 mSv 6.0 mSv
200 CXR 250 CXR 300 CXR

12. IIoonniizziinngg RRaaddiiaattiioonn....HHooww
eeffffeeccttss aarree pprroodduucceedd
IIoonniizziinngg RRaaddiiaattiioonn iiss tthhee
rreemmoovvaall ooff aann eelleeccttrroonn
ffrroomm aann aattoomm lleeaavviinngg aann
uunnssttaabbllee mmoolleeccuullee wwhhiicchh
mmaayy tthheenn bbrreeaakk aappaarrtt ttoo
ffoorrmm ffrreeee rraaddiiccaallss..
The weapon
http://www.paradigmlink.com/ionrad.shtml

13. LLiinneeaarr EEnneerrggyy TTrraannssffeerr ((LLEETT))
TThhee aavveerraaggee eenneerrggyy ddeeppoossiitteedd ppeerr uunniitt
lleennggtthh ooff ttrraacckk..
MMeeaassuurreedd iinn kkiillooeelleeccttrroonn vvoollttss ppeerr mmiiccrroonn
((1100--66 mm))

14. LLooww LLEETT // HHiigghh LLEETT
 LLooww LLEETT
LLooww mmaassss,, iinnccrreeaasseedd
ttrraavveell ddiissttaannccee ((ggaammmmaa rraayyss,, xx--
rraayyss))..
SSppaarrsseellyy iioonniizziinngg wwiitthh
rraannddoomm iinntteerraaccttiioonnss..
CCaauusseess ddaammaaggee pprriimmaarriillyy
tthhrroouugghh iinnddiirreecctt aaccttiioonn oorr
mmaayy ccaauussee ssiinnggllee ssttrraanndd
bbrreeaakkss ((wwhhiicchh aarree rreeppaaiirraabbllee))..
e-
http://staff.jccc.net/PDECELL/biochemistry/dna.gif

15. LLooww LLEETT // HHiigghh LLEETT
HHiigghh LLEETT
– LLaarrggee mmaassss,, ddeeccrreeaasseedd
ttrraavveell ddiissttaannccee ((aallpphhaa
ppaarrttiicclleess,, pprroottoonnss,, llooww
eenneerrggyy nneeuuttrroonnss))..
– CCaauusseess ddeennssee iioonniizzaattiioonn
aalloonngg iittss ppaatthh wwiitthh aa hhiigghh
pprroobbaabbiilliittyy ooff iinntteerraaccttiinngg
ddiirreeccttllyy wwiitthh DDNNAA..
α++
http://staff.jccc.net/PDECELL/biochemistry/dna.gif

16. IIoonniizziinngg RRaaddiiaattiioonn
The injury mechanism
TThhee rreeaaccttiioonnss ccaauusseedd bbyy iioonniizziinngg rraaddiiaattiioonn
ooccccuurr rraappiiddllyy,, tthheeyy aarree nnoonnsseelleeccttiivvee aanndd
rraannddoomm..
TThhee mmaajjoorriittyy ooff ddaammaaggee ccaauusseedd bbyy
rraaddiiaattiioonn iiss dduuee ttoo cchheemmiiccaall rreeaaccttiioonnss wwiitthh
wwaatteerr wwiitthhiinn tthhee cceellll..

17. H2O
HOH+
H+
OH*
Positively charged
water molecule
H* OH
-
e- + H2O
HOH-water
negatively charged
water molecule
Hydrogen
ion
Hydroxyl
electron radical water
hydrogen
radical
Hydroxyl
ion
The negatively charged
water molecule dissociates
into a hydrogen radical
and a hydroxyl ion.

18. RReeaaccttiioonnss
TThhee pprreevviioouuss rreeaaccttiioonnss pprroodduuccee ffrreeee
eelleeccttrroonnss ((ee--)),, tthhee iioonnss HH-- aanndd OOHH--,,
tthhee ffrreeee rraaddiiccaallss HH** aanndd OOHH**..
TThhee ffaattee ooff tthheessee pprroodduuccttss aarree…………..

19. FFrreeee RRaaddiiccaallss
AA ffrreeee rraaddiiccaall iiss aann aattoomm oorr
mmoolleeccuullee tthhaatt hhaass aann uunnppaaiirreedd
eelleeccttrroonn iinn iittss vvaalleennccee sshheellll..
TThheessee ffrreeee rraaddiiccaallss aarree
nnoonn--sseelleeccttiivvee wwhheenn ppaaiirriinngg uupp
wwiitthh eelleeccttrroonnss ffrroomm ootthheerr
aattoommss,, iinncclluuddiinngg tthhoossee tthhaatt
mmaakkee uupp tthhee DDNNAA mmoolleeccuullee..

20. DDiirreecctt AAccttiioonn // IInnddiirreecctt AAccttiioonn
DDiirreecctt AAccttiioonn
CCaauusseess ddaammaaggee ddiirreeccttllyy ttoo DDNNAA oorr ootthheerr iimmppoorrttaanntt
mmoolleeccuulleess iinn tthhee cceellll..
MMoorree lliikkeellyy wwhheenn tthhee bbeeaamm ooff cchhaarrggeedd ppaarrttiicclleess
ccoonnssiisstt ooff aallpphhaa ppaarrttiicclleess,, pprroottoonnss,, oorr eelleeccttrroonnss
IInnddiirreecctt AAccttiioonn
CCaauusseess ddaammaaggee bbyy iinntteerraaccttiinngg wwiitthh tthhee cceelllluullaarr
mmeeddiiuumm pprroodduucciinngg ffrreeee rraaddiiccaallss wwhhiicchh tthheenn ddaammaaggee
tthhee DDNNAA mmoolleeccuullee..
MMoorree lliikkeellyy wwhheenn xx--rraayyss oorr ggaammmmaa--rraayyss ccoommppoossee tthhee
bbeeaamm..

21. DDiirreecctt AAccttiioonn // IInnddiirreecctt AAccttiioonn

22. DDNNAA DDaammaaggee
 TThhee aarrrraannggeemmeenntt ooff nniittrrooggeennoouuss bbaasseess
pprroovviiddee aa bblluueepprriinntt ffoorr DDNNAA ffoorr tthhee ssyynntthheessiiss
ooff ssppeecciiffiicc pprrootteeiinnss nneecceessssaarryy ffoorr iinnddiivviidduuaall
cceellll ffuunnccttiioonn..
 IInn tthhee eevveenntt ooff aa lloossss oorr cchhaannggee ooff oonnee oorr
mmoorree ooff tthhee nniittrrooggeennoouuss bbaasseess........bbaassee
sseeqquueennccee aanndd nnoorrmmaall ffuunnccttiioonniinngg ooff tthhee cceellll
iiss aalltteerreedd..
 AAnnootthheerr ffoorrmm ooff DDNNAA ddaammaaggee dduuee ttoo
rraaddiiaattiioonn iinnvvoollvveess aa bbrreeaakk iinn tthhee hhyyddrrooggeenn
bboonnddss bbeettwweeeenn tthhee AAddeenniinnee –– TThhyymmiinnee aanndd
CCyyttoossiinnee –– GGuuaanniinnee bbaassee ppaaiirrss.. TThheessee
bboonnddss ffuunnccttiioonn ttoo kkeeeepp tthhee DDNNAA ssttrraannddss
ttooggeetthheerr
 BBoonnddss ccaann aallssoo bbrreeaakk bbeettwweeeenn ddeeooxxyyrriibboossee
ssuuggaarr aanndd tthhee pphhoosspphhaattee ggrroouuppss wwhhiicchh ccaann
lleeaadd ttoo ccrroossss--lliinnkkiinngg ooff DDNNAA
The target

23. CChhrroommoossoommee AAbbeerrrraattiioonnss
 IIff tthhee cchhrroommoossoommee ffrraaggmmeennttss aarree
nneeaarr oonnee aannootthheerr tthheeyy hhaavvee aa hhiigghh
cchhaannccee ooff rreeaattttaacchhiinngg iinn tthheeiirr
oorriiggiinnaall ppoossiittiioonn –– ccaauussiinngg nnoo ffuuttuurree
ddaammaaggee ttoo tthhee cceellll..AA pprroocceessss kknnoowwnn
aass rreessttiittuuttiioonn..
 IInn ttrraannssllooccaattiioonnss aanndd iinnvveerrssiioonnss,, nnoo
ggeenneettiicc iinnffoorrmmaattiioonn iiss lloosstt,, bbuutt tthhee
rreeaarrrraannggeemmeenntt ooff ggeennee sseeqquueennccee
wwiillll aalltteerr pprrootteeiinn ssyynntthheessiiss..
 IInn aa ddeelleettiioonn,, aa cchhrroommoossoommee
ffrraaggmmeenntt iiss nnoott rreepplliiccaatteedd dduurriinngg tthhee
nneexxtt mmiittoossiiss,, tthhee ggeenneettiicc iinnffoorrmmaattiioonn
iiss lloosstt.. TThhee eeffffeeccttss tthhiiss hhaass oonn tthhee
cceellll ddeeppeennddss oonn tthhee aammoouunntt aanndd
ttyyppee ooff iinnffoorrmmaattiioonn lloosstt..
The effects
Inversion
Translocation
Deletion

24. Chromosome deletion
Chromosome translocation

25. Outcomes after cell exposure
DAMAGE
REPAIRED
DAMAGE TO DNA
CELL DEATH
(APOPTOSIS)
TRANSFORMED
CELL
IAEA 3 : Biological effects of ionizing radiation

26. DNA Mutation
Mutation
repaired
Cell survives
but mutated
Viable Cell
Cancer ?
Cell death
Unviable Cell

27. Repair of DNA damage
• RADIOBIOLOGISTS
ASSUME THAT THE
REPAIR SYSTEM IS
NOT 100%
EFFECTIVE.
IAEA 3 : Biological effects of ionizing radiation

28. CCaanncceerr iinniittiiaattiioonn

29. NORMAL TISSUE

30. CELL INITIATION
An initiating event
creates a mutation in
one of the basal cells

31. DYSPLASIA
More mutations occurred.
The initiated cell has
gained proliferative
advantages.
Rapidly dividing cells
begin to accumulate
within the epithelium.

32. BENIGN TUMOR
More changes within
the proliferative cell line lead
to full tumor development.

33. MALIGNANT TUMOR
The tumor breaks trough
the basal lamina.
The cells are irregularly
shaped and the cell line is
immortal. They have an increased
mobility and invasiveness.

34. METASTASIS
Cancer cells break through
the wall of a lymphatic
vessel or blood capillary.
They can now migrate
throughout the body and
potentially seed new tumors.

35. A simple generalized scheme for multistage oncogenesis
Damage to chromosomal DNA
of a normal target cell
Failure to correct
DNA repair
Appearance of specific
neoplasia-initiating mutation
Promotional growth
of pre-neoplasm
Conversion to overtly
malignant phenotype
Malignant progression
and tumour spread

36. RRaaddiioosseennssiittiivviittyy
AAccttiivveellyy rreepprroodduucciinngg cceellllss aarree mmoorree
rraaddiioosseennssiittiivvee tthhaann mmaattuurree cceellllss..
DDuurriinngg mmiittoossiiss,, tthhee cceellll iiss iinn aa ssttrreesssseedd
ssttaattee aanndd sshhoowwss aann iinnccrreeaassee iinn ddaammaaggee
ccaauusseedd bbyy rraaddiiaattiioonn..
CCeellllss tthhaatt hhaavvee ddeeccrreeaasseedd lleevveellss ooff
ddiiffffeerreennttiiaattiioonn aarree mmoorree rraaddiioosseennssiittiivvee
tthhaann ssppeecciiaalliizzeedd cceellllss..

37. The Cell Cycle
 An ordered set of events,
culminating in cell growth and
division into two daughter
cells
 Tc, full mitotic cycle
G2
(2nd gap)
M
(mitosis)
S
(DNA Synthesis phase)
G1
(1st gap)
Cells that
cease
division

38. Radiosensitivity & Mitotic Cycle
 Cell cycle components
 M, G1, S, G2
 Cell cycles times vary largely due to G1
 crypt cells, 9 - 10 hours
 stem cells (mouse skin) 200 hr
 Sensitivity
 Cells most sensitive close to mitosis
 Resistance greatest in latter part of S
 For long G1’s, there is an early resistance period followed by
sensitive one at the end of G1
 G2 ~ M in sensitivity

39. Radiosensitivity
High RS Medium RS Low RS
Muscle
Bones
Nervous
system
Skin
Mesoderm
organs (liver,
heart, lungs…)
Bone Marrow
Spleen
Thymus
Lymphatic
nodes
Gonads
Eye lens
Lymphocytes
(exception to the RS laws)
IAEA 3 : Biological effects of ionizing radiation

40. FFrraaccttiioonnaattiioonn iinn rraaddiiootthheerraappyy
 IInnsstteeaadd ooff aa ssiinnggllee ttrreeaattmmeenntt
ccoonnssiissttiinngg ooff aa hhiigghh ddoossee,,
ffrraaccttiioonnaattiioonn ddiivviiddeess tthhee ddoossee ttoo
bbee ddeelliivveerreedd oovveerr aa ppeerriioodd ooff ttiimmee,,
uussuuaallllyy 66--88 wweeeekkss..
 AAtt llooww ddoosseess ooff rraaddiiaattiioonn,,
nnoorrmmaall cceellllss hhaavvee aann iinnccrreeaasseedd
ssuurrvviivvaall rraattee bbeeccaauussee ooff tthheeiirr
aabbiilliittyy ttoo rreeppaaiirr ssuubblleetthhaall
ddaammaaggee bbeeffoorree tthhee nneexxtt ffrraaccttiioonn ooff
rraaddiiaattiioonn iiss ddeelliivveerreedd..
 TTuummoorr cceellllss ddoo nnoott ppoosssseessss tthhee
rreeppaaiirr eennzzyymmeess nneecceessssaarryy ttoo
kkeeeepp uupp wwiitthh tthhee rreeppaaiirrss aanndd
aass aa rreessuulltt tthhee cceellll iiss
oovveerrwwhheellmmeedd aanndd iiss ddeessttrrooyyeedd..
http://www.usoncology.com/CompanyInfo/PhotoLibrary.asp

41. Dose-Response Relationships
 Two effects of radiation
exposure:
 deterministic (threshold)
 stochastic: cancer
 Radiation Standards
 set below threshold
 set to limit stochastic risk

42. Non-Stochastic (Deterministic) Effects
 Occurs above threshold
dose
 Severity increases with
dose
 Alopecia (hair loss)
 Cataracts
 Erythema (skin reddening)
 Radiation Sickness
 Temporary Sterility

43. Stochastic (Probabilistic) Effects
 Occurs by chance
 Probability increases with dose
 Carcinogenesis
 Mutagenesis
 Teratogenesis

44. Radiation health effects
CELL DEATH
DETERMINISTIC
Somatic
Clinically attributable
in the exposed
individual
STOCHASTIC
somatic & hereditary
epidemiologically
attributable in large
populations
ANTENATAL
somatic and
hereditary expressed
in the foetus, in the live
born or descendants
IAEA 3 : Biological effects of ionizing radiation
BOTH
TYPE
OF
EFFECTS
CELL TRANSFORMATION

45. Radiation effects and
Syndromes

46. Injury
Threshold
Dose to
Skin (Sv)
Weeks to
Onset
Early transient erythema 2 <<1
Temporary epilation 3 3
Main erythema 6 1.5
Permanent epilation 7 3
Dry desquamation 10 4
Invasive fibrosis 10
Dermal atrophy 11 >14
Telangiectasis 12 >52
Moist desquamation 15 4
Late erythema 15 6-10
Dermal necrosis 18 >10
Secondary ulceration 20 >6
IAEA 3 : Biological effects of ionizing radiation
Skin damage
from prolonged
fluoroscopic
exposure
Skin reactions

47. Skin injuries
IAEA 3 : Biological effects of ionizing radiation

48. Effects in eye
• Eye lens is highly RS.
• Coagulation of proteins
occur with doses
greater than 2 Gy.
• There are 2 basic
effects:
Histologic view of eye:
From “Atlas de Histologia...”. J. Boya
Detectable 0.5-2.0 > 0.1
opacities
Eye lens is highly RS,
moreover, it is surrounded by
highly RS cuboid cells. 5.0 > 0.15
Visual
impairment
(cataract)
IAEA 3 : Biological effects of ionizing radiation
Sv/year for
many years
Sv single brief
exposure
Effect

49. Whole body response: adult
Acute irradiation
syndrome Chronic irradiation
syndrome
Steps:
1. Prodromic
(onset of
disease)
2. Latency
3. Manifestation
Lethal dose 50 / 30
IAEA 3 : Biological effects of ionizing radiation 49
Survival time
Dose
BONE
MARROW GASTRO
INTESTINA
L CNS
(central nervous
system)
1-10 Gy
10 - 50 Gy
> 50 Gy
•Mechanism:
Neurovegetative
disorder
•Similar to a sick
feeling
•Quite frequent in
fractionated
radiotherapy

50. Threshold Doses for Deterministic
Effects
• Cataracts of the lens of the
eye 2-10 Gy
• Permanent sterility
• males 3.5-6 Gy
• females 2.5-6 Gy
• Temporary sterility
• males 0.15 Gy
• females 0.6 Gy
Severity of
effect
dose
threshold

51. Symptoms of Acute Radiation Sickness
 Three categories (E. Hall, 1994)
 Hemopoietic: 3-8 Gy LD50/60
 radiation damages precursors to red/white blood cells &
platelets
 prodromal may occur immediately
 symptoms: septicemia,
 survival mixed
 examples include Chernobyl personnel (203 exhibited
symptoms, 13 died)

52. Symptoms, continued
 Gastrointestinal : >10 Gy
 radiation depopulates GI epithelium (crypt cells)
 abdominal pain/fever, diarrhea, dehydration
 death 3 to 10 days (no record of human survivors above 10
Gy)
 examples include Chernobyl firefighters
 Cerebrovascular : > 100 Gy
 death in minutes to hours

53. Delayed Effects
 SOMATIC: they affect the health of the
irradiated person. They are mainly different
kinds of cancer (leukemia is the most
common, with a delay period of 2-5 years,
but also colon, lung, stomach cancer…)
 GENETIC: they affect the health of the
offspring of the irradiated person. They are
mutations that cause malformation of any
kind (such as mongolism)

55. RADIATION PROTECTION
Based on two components.
A) JUSTIFICATION.
B) OPTIMIZATION.
JUSTIFICATION:-
Applications of ionising radiation are only justified
when they provide a net benefit with minimization of
risks of radiation for people.

56. GUIDELINES FOR REFERRING PHYSICIANS:-
1) Repeating investigations which have already been
done:
For example at other hospital, in an outpatient department,
or in an accident and emergency department.
HAS IT BEEN DONE ALREADY? Every attempt should be made
to get previous films.
2) Investigation when results are unlikely to affect
patient management:
The anticipated 'positive' finding is usually irrelevant, e.g.
degenerative spinal disease (as 'normal' as white hairs in old
age) or because a positive finding is so unlikely. DO I NEED
IT?

57. 3) Investigating too often:-
i.e. before the disease could have progressed or resolved or
before the results could influence treatment. DO I NEED IT
NOW? Or some clinicians tend to rely on investigations more
than others. ARE TOO MANY INVESTIGATIONS BEING
PERFORMED?
4) Doing the wrong investigation:-
Imaging techniques are developing rapidly. It is often helpful to
discuss an investigation with a specialist in clinical radiology or
nuclear medicine before it is requested. IS THIS THE BEST
INVESTIGATION?
5) Failing to provide appropriate clinical information &
questions that imaging Investigation should answer.
Deficiencies here may lead to the wrong technique being used
(e.g. the omission of an essential view). HAVE I EXPLAINED THE
PROBLEM?

58. OPTIMIZATION:-
Once a practice is
justified, the exposure to
ionising radiation should
be kept as low as
reasonably achievable
(ALARA).

59. FUNDAMENTAL
PRINCIPLES OF
RADIATION
PROTECTION:
1. Distance.
2. Exposure time.
3. Barriers & Shielding.

60. DISTANCE
INVERSE SQUARE LAW:
Intensity of radiation is inversely proportional to
the square of the distance from the source of radiation.
In equation form:
For Example: If the
dose is 9 R at 3
feet, stepping back
to a distance of
6 feet will cause
the dose to
decrease to 2.25 R.

61. 57cm from x-ray source 50cm from x-ray source

62. EXPOSURE TIME
 The amount of radiation received is proportional to
the length of the exposure time.
 Minimized by conducting
procedures as quickly as possible.
 For Example, using short
bursts of fluoroscopy.
Employing image intensifiers &
Intensifying screens.
Using high kVp , low maS
techniques.

63. BARRIERS & SHIELDING
 The most commonly used protective material is lead.
It has a double advantage of high density and high
atomic number.
 Lead equivalent: it is the thickness of lead which
provide the same degree of protection as the material.
ROOM SHIELDING:
 Should be located as far as away from areas of high
occupancy and general traffic.
 Wall on which primary beam falls should not be less
than 35 cm thick brick or equivalent.
 Shielding of 1.7mm lead (23 cm brick) in front of doors
& windows of x-ray room.

64. X-RAY CONTROL
ROOM:
Walls & viewing
windows of control
booth should have lead
equivalent of 1.5 mm.
Distance between
control panel & X-ray
unit / chest
stand should be
minimum 3 meters.

65. PATIENT WAITING ROOM:
 Provided outside X-ray room a proper warning signal
when unit is in use.
 Warning devices may include audible and visual
signs.

66. LEAD APRON:-
 Typically thickness of 0.5
mm lead equivalent is
used.
 Weight ranges from 2.5 to
7 kg.
 Should cover much of red
bone marrow & breast.
LEAD GLOVES:
 Lead salts or metallic lead
are added to rubber or
plastic.
 Lead equivalent of these
is about ¼ mm.

67. LEAD GLASS:
 Made by adding lead salts to silicates , in the
manufacturing of glass.
 It is acceptably transparent and a better protective
material.
 Contains 60% of lead by weight.
GONADAL SHIELDING:
 Must be 0.5 mm of lead.
 Must be used when gonads will lie within 5 cm of the
collimated area.
 Separate male vs. female shielding available.

68. LEAD GLOVES
LEAD GLASSES

69. OVARIAN PROTECTION
THYROID COLLER
MALE GONADAL
SHIELD

70.  Have standard projections for specific indications.
 Additional views - on a case-by-case basis
 Use PA projections, where practical, for chest and spine
radiographs.
 Avoid repeating exposures.
 Use safe exposure factors – high KVp and low mAs
technique.
Never stand in the primary beam.
Always wear protective apparel when not behind a
protective barrier.
Always wear a radiation monitor and position it outside the
protective apron at collar level.
The person holding the patient must wear protective apron
and if possible gloves.
Always collimate to smallest field size appropriate to
examination.

71. RADIATION MONITORING DEVICES
Non-Self Reading Devices:
1) FILM BADGES:
 Consist of a small dental–sized film wrapped in light proof
paper and mounted in a holder filled with metallic filters of
different thicknesses.
2) THERMOLUMINESCENT DOSIMETERS (TLD):
 They are used to measure external
individual whole body doses from
X-rays , beta rays & gamma radiation.
 It consists of a TLD card loaded in a
cassette (card holder ) having suitable
metallic & plastic filters.

72. TLD Ring or Finger badges:
 Ring or finger badges are worn by fluoroscopists &
interventional radiologists who usually receive high
doses to their extremities.
 The ring dosimeter contains a small radiation-sensitive
lithium fluoride crystal.

73. SELF READING DEVICES:
Real time dose information available
Needs frequent Calibration checks
Can be taken from hospital to hospital.
Good for visiting consultants
surgeons, anesthetists,
urologists, gastroenterologists
etc.

74. Summary
 Ionizing radiation use should be only used
when benefit outweighs possible risks.
 Every examination should be justified.
 Optimized protocols for lowering patient dose
without affecting accurate diagnosis should
be done.
 Use all kinds of radiation protection during
work...It's your life.!

75. Where to Get More Information (1)
• The 2007 Recommendations of the International
Commission on Radiological Protection, ICRP 103,
Annals of the ICRP 37(2-4):1-332 (2007)
• UNSCEAR 2008 Report to the General Assembly,
with scientific annexes, United Nations Scientific
Committee on the Effects of Atomic Radiation,
United Nations, Vienna, Austria, 2008
• Avoidance of radiation injuries from medical
interventional procedures. ICRP Publication 85.
Ann ICRP 2000;30 (2). Elsevier
IAEA 3 : Biological effects of ionizing radiation 75