This document discusses radiation protection. It states that ionizing radiation can potentially harm biological tissues by changing the normal structure and function of tissue atoms. While any level of exposure may cause damage, repair is usually possible from low-level exposures. Natural sources, such as cosmic rays and radon, account for about 83% of radiation exposure, while man-made sources like medical procedures and consumer products make up the remaining 17%. The concepts of limiting exposure as much as reasonably achievable and weighing the risks versus benefits of exposure are discussed. Standards and guidelines aim to appropriately limit risk of bodily injury from radiation.

2. Radiation ProtectionRadiation Protection

3. Unit II 3
Background InformationBackground Information
• Potentially harmful to biologic tissuesPotentially harmful to biologic tissues
• Ionization of tissue atoms can changeIonization of tissue atoms can change
the normal structure & functionthe normal structure & function
• Any level of exposure may causeAny level of exposure may cause
damagedamage
• Repair is possible to the damageRepair is possible to the damage
from low levels of exposurefrom low levels of exposure
most of timemost of time

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SOURCES OF IONIZING RADIATIONSOURCES OF IONIZING RADIATION
 Natural sources:Natural sources: ~83%~83%
External-15%External-15%
– cosmic (from space)cosmic (from space)
– terrestrial (from earth)terrestrial (from earth)
InternalInternal (in the body)(in the body)
– radon (radioactive gas)radon (radioactive gas)
 Manmade sources: ~17%Manmade sources: ~17%
– diagnostic x-ray proceduresdiagnostic x-ray procedures
– nuclear medicine proceduresnuclear medicine procedures
– consumer productsconsumer products
– otherother

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Concepts of Radiation ProtectionConcepts of Radiation Protection
 limiting ionizing radiation exposurelimiting ionizing radiation exposure
Uses ALARA conceptUses ALARA concept
– AAss LLowow AAss RReasonablyeasonably AAchievablechievable
ALARP-ALARP- AAss LLowow AAss RReasonablyeasonably PPracticableracticable
 Use of radiation in terms ofUse of radiation in terms of RISKRISK vs.vs.
BENEFITBENEFIT
 Provides Standards and Guidelines (S&G)Provides Standards and Guidelines (S&G)
for appropriate use of radiationfor appropriate use of radiation

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ALARAALARA
 GOAL:GOAL: decrease exposure wheneverdecrease exposure whenever
possiblepossible
 doesdoes notnot eliminate radiationeliminate radiation
exposureexposure
 providesprovides guidelinesguidelines toto limit the risklimit the risk
of bodily injuryof bodily injury

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RISK vs. BENEFITRISK vs. BENEFIT
 all exposure hasall exposure has "potential""potential" for harmfor harm
 BenefitBenefit must outweigh Rmust outweigh Riskisk
BENEFIT:BENEFIT: improvement in the person’s lifeimprovement in the person’s life
RISK:RISK: a possible harmful effecta possible harmful effect
(perceived or actual)(perceived or actual)
 requires use of good judgmentrequires use of good judgment

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Common RisksCommon Risks
AccidentAccident
FatalityFatality
risk/yearrisk/year
Motor vehicleMotor vehicle 1:4,0001:4,000
FallFall 1:10,0001:10,000
FireFire 1:25,0001:25,000
LighteningLightening 1:1,000,0001:1,000,000
RadiationRadiation 1:300,000,0001:300,000,000

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Standards & Guidelines (S&G)Standards & Guidelines (S&G)
set by the scientific communityset by the scientific community
Central & state legislation basedCentral & state legislation based
on S&Gon S&G

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DOSEDOSE LIMITATIONSLIMITATIONS
 Maximum permissible doseMaximum permissible dose (MPD(MPD))
established by NCRPestablished by NCRP
– doses with andoses with an acceptably small riskacceptably small risk toto
the individual & societythe individual & society
– doesdoes notnot include exposure from naturalinclude exposure from natural
sources (background) of radiationsources (background) of radiation
– providesprovides upper limitsupper limits of acceptableof acceptable
exposureexposure
MPD for general public – 1mSvMPD for general public – 1mSv
MPD for operator-6 mSvMPD for operator-6 mSv

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Radiation ProtectionRadiation Protection
 OperatorOperator
 PatientPatient
 PublicPublic

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Protection -- OperatorProtection -- Operator
 Never hold the film for the patient duringNever hold the film for the patient during
exposureexposure
 Never stabilize the x ray tube duringNever stabilize the x ray tube during
exposureexposure
 Never stand in the path of primary radiationNever stand in the path of primary radiation
 Should stand 6 feet away from the primaryShould stand 6 feet away from the primary
beam, at an angle of 90 to 135 degreebeam, at an angle of 90 to 135 degree
 Should stand behind the lead barrier havingShould stand behind the lead barrier having
0.5 mm lead equivalent or leave the room0.5 mm lead equivalent or leave the room
during exposure.during exposure.

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 Keep accurate occupational exposureKeep accurate occupational exposure
recordsrecords
– always wear your exposure badgealways wear your exposure badge
– change your badge at the appropriate timechange your badge at the appropriate time
– check the exposure report monthlycheck the exposure report monthly
 wear lead gloves if your hands comewear lead gloves if your hands come
near the direct beam and patientnear the direct beam and patient

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Patient ProtectionPatient Protection
 Radiograph taken only if it is neededRadiograph taken only if it is needed
 Good and properly maintained machine should beGood and properly maintained machine should be
usedused
 ALARA principle should be followedALARA principle should be followed
 High speed film should be usedHigh speed film should be used
 Adequate training in radiographic techniques to avoidAdequate training in radiographic techniques to avoid
poor quality radiographspoor quality radiographs
 Proper maintenance of the processing solutions,Proper maintenance of the processing solutions,
processor and dark roomprocessor and dark room
 Restriction of beam by Rectangular collimatorsRestriction of beam by Rectangular collimators
 Long cone machines should be usedLong cone machines should be used

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 Adequate thickness Aluminum filters should beAdequate thickness Aluminum filters should be
used.used.
 Lead aprons 0.25mm, thyroid collars can be usedLead aprons 0.25mm, thyroid collars can be used
 Use intensifying screens for extra oral radiographyUse intensifying screens for extra oral radiography
 Use film holders for placing the film.Use film holders for placing the film.
 Use beam withUse beam with↑↑kVp andkVp and ↓↓mAmA
 Set exposure time correctly.Set exposure time correctly.

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Pregnancy PrecautionsPregnancy Precautions
 always askalways ask
 Avoid taking radiographsAvoid taking radiographs
 Shield pelvic areaShield pelvic area

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Protection for publicProtection for public
 Never allow other people in the controlled areaNever allow other people in the controlled area
 X ray beam to be directed towards outside wallX ray beam to be directed towards outside wall
and not to corridors or occupied roomsand not to corridors or occupied rooms
 Hazard light and sign on the doorHazard light and sign on the door
 Walls of the room should be coated with bariumWalls of the room should be coated with barium
plaster or lined with lead or should haveplaster or lined with lead or should have
adequate thicknessadequate thickness
 Radiation exposure to the room should beRadiation exposure to the room should be
monitored.monitored.

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F speedF speed 25% reduction than E25% reduction than E
DigitalDigital 40% reduction than F40% reduction than F
Rare earth IntensifyingRare earth Intensifying
screenscreen
55% reduction than55% reduction than
normal ISnormal IS
Long focal spotLong focal spot 32% reduction32% reduction
Rectangular collimatorRectangular collimator 60% reduction over60% reduction over
circularcircular
Filtration with 3mm AlFiltration with 3mm Al 20% reduction than no20% reduction than no
filtrationfiltration
Lead apronLead apron 98% reduction to gonads98% reduction to gonads
Thyroid collarsThyroid collars 92% reduction to thyroid92% reduction to thyroid
↑↑kVp,kVp, ↓↓mAmA ↓↓ ExposureExposure

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Methods of monitoring & measuringMethods of monitoring & measuring
radiation doseradiation dose
 Film BadgeFilm Badge
 Thermoluminescent dosimetersThermoluminescent dosimeters
 Ionization chamberIonization chamber

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Film badgeFilm badge
 Plastic frame with a variety of differentPlastic frame with a variety of different
metal filters and a small radiographic filmmetal filters and a small radiographic film
which reacts to radiationwhich reacts to radiation

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Thermoluminescent dosimetersThermoluminescent dosimeters
 They contain materials like lithiumThey contain materials like lithium
fluoride which absorb radiation and thenfluoride which absorb radiation and then
release the energy in the form of lightrelease the energy in the form of light
 The intensity of the emitted light isThe intensity of the emitted light is
proportional to the radiation energyproportional to the radiation energy
absorbedabsorbed
 It is reusableIt is reusable

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Ionization chambersIonization chambers
 Radiation produces ionization of airRadiation produces ionization of air
molecules inside the closed chamber,molecules inside the closed chamber,
which results in a measurable dischargewhich results in a measurable discharge
 Most accurate methodMost accurate method

23. Thank youThank you