UNIT 6UNIT 6Introduction to Radiation Introduction to Radiation

ProtectionProtection

Goal of Radiation Goal of Radiation Protection:Protection:

To minimize exposure to To minimize exposure to the patient and the the patient and the

operator operator ALARA ConceptALARA Concept

What is radiation?What is radiation?Radiation is a form of energy; Radiation is a form of energy;

“Electromagnetic radiation”.“Electromagnetic radiation”.More specifically, it is a form of More specifically, it is a form of

radiant energyradiant energy..Ionizing radiation (IR) has the Ionizing radiation (IR) has the

ability to cause chemical and ability to cause chemical and biological changes through biological changes through ionization.ionization.

Electromagnetic SpectrumElectromagnetic Spectrum

These are the different types of electromagnetic radiation. Cosmic radiation has the most energy on the spectrum; Infrared has the least energy. The more energy the radiation has, the more its ability to penetrate matter.

Types of RadiationTypes of Radiation

Type Type Charge Symbol Charge Symbol

Alpha (particulate)+2 Alpha (particulate)+2 chargechargeBeta (particulate) -1 chargeBeta (particulate) -1 chargeGamma (e-m) no chargeGamma (e-m) no chargeX-Ray (e-m) no charge XX-Ray (e-m) no charge X

Characteristics of Characteristics of X-RaysX-Rays

InvisibleInvisible

Highly penetratingHighly penetrating

Ability to ionize matterAbility to ionize matter

Travel in straight linesTravel in straight lines

Travel at the speed of light in a vacuumTravel at the speed of light in a vacuum

Cause chemical and biological changes Cause chemical and biological changes (due to ionization)(due to ionization)

Produce scattered/secondary radiationProduce scattered/secondary radiation

Sources of RadiationSources of Radiation

Natural Natural Background Background RadiationRadiation

Manmade Manmade RadiationRadiation

3 Types of Natural Background 3 Types of Natural Background RadiationRadiation

Cosmic Cosmic radiation from the sun & starsradiation from the sun & stars

Terrestrial Terrestrial radiation from radioactive radiation from radioactive elements in the earthelements in the earth

Internal Internal radiation from inside the bodyradiation from inside the body

Manmade Radiation from...Manmade Radiation from...

Medical and Dental Medical and Dental X-RaysX-Rays

Nuclear ReactorsNuclear Reactors

Radioactive FalloutRadioactive Fallout

Percent exposure to various types of Percent exposure to various types of ionizing radiationionizing radiation

Most radiosensitive organsMost radiosensitive organs

Lens of the eyesLens of the eyes

Bone marrowBone marrow

GonadsGonads

ThyroidThyroid

Main Principles of ProtectionMain Principles of Protection

TimeTime

DistanceDistance

ShieldingShielding

Devices/Methods to Reduce Devices/Methods to Reduce Operator ExposureOperator Exposure

Reduce time of exposureReduce time of exposure

Don’t hold patients during exposure Don’t hold patients during exposure

Get it right the first time! Reduce Get it right the first time! Reduce repeats!repeats!

Operator ProtectionOperator Protection

Utilize Shielding Utilize Shielding AvailableAvailable

Lead Aprons, Lead Aprons, Gloves, Thyroid Gloves, Thyroid Shields, Pb GogglesShields, Pb Goggles

Stand behindStand behind Pb Pb Control Booth Control Booth during exposuresduring exposures

Operator ProtectionOperator ProtectionDistance yourself from the source of Radiation Distance yourself from the source of Radiation (ie. The tube or the patient)(ie. The tube or the patient)

Distance yourself from the patient during exposures. Distance yourself from the patient during exposures. Patient is the greatest source of scatter-Patient is the greatest source of scatter- (Fluoroscopy and Mobile)(Fluoroscopy and Mobile)

Distance yourself from the X-Ray Tube Distance yourself from the X-Ray Tube (source of x-rays)(source of x-rays)

Wear personnel monitoring device correctly to Wear personnel monitoring device correctly to develop and awareness of exposure you receive. develop and awareness of exposure you receive. (at the collar level & outside the Pb apron when one is (at the collar level & outside the Pb apron when one is worn)worn)

Devices/Methods to Reduce Patient Devices/Methods to Reduce Patient ExposureExposure

Use ofUse of Beam Beam Limitation Limitation -- Cones Cones, , CollimatorsCollimators, , DiaphragmsDiaphragms, , PBL PBL (Positive Beam (Positive Beam Limitation)Limitation)

This reduces patient This reduces patient exposure and exposure and scattered radiationscattered radiation

Devices/Methods to Reduce Patient Devices/Methods to Reduce Patient ExposureExposure

Use of Use of Filtration Filtration - - Al (Aluminum) Al (Aluminum) filters protect filters protect patient skin patient skin exposureexposure

2.5 mm Al filtration 2.5 mm Al filtration is required for is required for equipment using equipment using 70 kVp or higher70 kVp or higher

Devices/Methods to Reduce Devices/Methods to Reduce Patient ExposurePatient Exposure

High KvP / Low mAs High KvP / Low mAs exposures are best for exposures are best for the patient.the patient.

mAs is mAs is directly directly proportionalproportional to the to the amount of exposure the amount of exposure the patient receives.patient receives.

Use of higher kVp Use of higher kVp increases penetration increases penetration thus reduces absorption.thus reduces absorption.

Patient ProtectionPatient Protection

For conventional systems, use of high For conventional systems, use of high speed film/screen systems reduce the speed film/screen systems reduce the amount of exposure required.amount of exposure required.

ReduceReduce repeats repeats ie: use short exposure ie: use short exposure times which eliminate motion (blurry times which eliminate motion (blurry pictures), Use pictures), Use immobilization devices immobilization devices to to prevent patient movement.prevent patient movement.

UseUse gonad shielding gonad shielding (when indicated)(when indicated) toto reduce patient gonad dose.reduce patient gonad dose.

Measurement of RadiationMeasurement of RadiationTraditional Traditional

UnitUnit

SI UnitSI Unit DefinitionDefinition

Exposure Exposure

in Air in Air

Roentgen Roentgen

““R”R”Coulombs/kGCoulombs/kG

(C/kG)(C/kG)

1.08X101.08X1099 ion ion pairs/ccpairs/cc

Absorbed Absorbed

DoseDose

Radiation Radiation Absorbed DoseAbsorbed Dose

““Rad”Rad”

Gray (Gy)Gray (Gy) 100 ergs/gm100 ergs/gm

Dose Dose EquivalentEquivalent

Radiation Radiation Equivalent ManEquivalent Man

““Rem”Rem”

Sievert (Sv)Sievert (Sv) Rad x QFRad x QF

RadioactivityRadioactivity CurieCurie

(Ci)(Ci)

BecquerelBecquerel

(Bq)(Bq)

3.7X103.7X101010dpsdps

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