Radiation Safety Training for Radiation Safety Training for Medical Imaging StudentsMedical Imaging Students

Deputy Radiation Safety Officer:Deputy Radiation Safety Officer:Michael “Ike” Hall, CHP, CSPEmory University Hospital

404-712-7867

TopicsTopics

Fundamentals of RadiationFundamentals of Radiation Radiation Limits and DosimetryRadiation Limits and Dosimetry Biological Effects of RadiationBiological Effects of Radiation Radiation and PregnancyRadiation and Pregnancy Fluoroscopy and Patient InjuriesFluoroscopy and Patient Injuries Worker ProtectionWorker Protection

What is radiation?What is radiation?

Radiation is energy emitted from Radiation is energy emitted from unstable atoms. Radiation can be in unstable atoms. Radiation can be in the form of subatomic particles (alpha the form of subatomic particles (alpha or beta particles) or electromagnetic or beta particles) or electromagnetic radiation (X and gamma rays). radiation (X and gamma rays). Radiation that is energetic enough to Radiation that is energetic enough to change the chemistry of a target is change the chemistry of a target is called ionizing radiation, and that will called ionizing radiation, and that will be the focus of this training.be the focus of this training.

Ionizing RadiationIonizing Radiation

Ion: atom with a positive or negative Ion: atom with a positive or negative charge (i.e., too few or too many charge (i.e., too few or too many electrons)electrons)

Radiation that is energetic enough Radiation that is energetic enough can strip electrons and create ionscan strip electrons and create ions

Ionization can change molecular Ionization can change molecular chemistry or break apart moleculeschemistry or break apart molecules

Radiation BiologyRadiation Biologyin a nutshellin a nutshell

Ionizing radiation harms biological systems by two means:

Indirectly - Production of Free Radicals

Directly - DNA damage

Four Possible OutcomesFour Possible Outcomes

Cells are undamaged by the doseCells are undamaged by the dose Cells are damaged, repair the Cells are damaged, repair the

damage and operate normallydamage and operate normally Cells are damaged, repair the Cells are damaged, repair the

damage and operate abnormallydamage and operate abnormally Cells die as a result of the damageCells die as a result of the damage

Measuring RadiationMeasuring Radiation

Exposure: measure of ionization in Exposure: measure of ionization in air (roentgen, or R)air (roentgen, or R)

Absorbed dose: energy deposited in Absorbed dose: energy deposited in material per unit mass (Gray or rad)material per unit mass (Gray or rad)

1 Gray = 1 Joule/kg = 100 rad1 Gray = 1 Joule/kg = 100 rad

Measuring RadiationMeasuring Radiation

Equivalent dose: measure of the Equivalent dose: measure of the biological effect of a specific kind of biological effect of a specific kind of radiation on humans (Sieverts or rem)radiation on humans (Sieverts or rem)

For x-rays, dose and dose equivalent For x-rays, dose and dose equivalent are equal. Dose equivalence may be are equal. Dose equivalence may be different for some radioactive particles.different for some radioactive particles.

1 Gray = 1 Sievert = 100 rem1 Gray = 1 Sievert = 100 rem

How much radiation is harmful?How much radiation is harmful?

Radiogenic health effects (primarily Radiogenic health effects (primarily cancer) are observed in humans only cancer) are observed in humans only at doses in excess of 10 rem at doses in excess of 10 rem delivered at high dose rates. Below delivered at high dose rates. Below this dose, estimation of adverse this dose, estimation of adverse health effect is speculative.health effect is speculative.

““Radiation Risk in Perspective”Radiation Risk in Perspective”Health Physics SocietyHealth Physics Society

How much radiation is in the How much radiation is in the environment?environment?

People are exposed to background People are exposed to background radiation continuously.radiation continuously.

The average dose due to background The average dose due to background exposure is around 350 millirem per exposure is around 350 millirem per year in the United States.year in the United States.

Background exposure can vary with Background exposure can vary with altitude, soil, and medical usage.altitude, soil, and medical usage.

Background Radiation Background Radiation SourcesSources

55%

27%

2%

15%1%

Radon (198 millirem)

Cosmic, terrestrial, internal (97millirem)

Consumer products (7 millirem)

Medical (54 millirem)

Other (4 millirem)

Terrestrial RadiationTerrestrial Radiation

units in mGy/yearTerrestrial radiation only

Even the highest known levels of background radiation have not proven to increase the risk to residents.

Even the highest known levels of background radiation have not proven to increase the risk to residents.

Radiation Safety PrinciplesRadiation Safety Principles

The Radiation Safety program, The Radiation Safety program, including training, monitoring, and including training, monitoring, and contamination control, is designed to contamination control, is designed to ensure that no worker receives a ensure that no worker receives a radiation dose in excess of regulatory radiation dose in excess of regulatory limits, and that each worker generally limits, and that each worker generally receives only as much exposure as receives only as much exposure as necessary to do one's job.necessary to do one's job.

Radiation Safety PrinciplesRadiation Safety Principles

TimeTime

DistanceDistance

ShieldingShielding

ContainmentContainment

TimeTime

Dose is directly proportional to the time Dose is directly proportional to the time spent near radiation and radioactive spent near radiation and radioactive materialsmaterials

Minimize time near radiation producing Minimize time near radiation producing machines and radioactive materials or machines and radioactive materials or patients whenever possiblepatients whenever possible

Plan work activities so as to spend less Plan work activities so as to spend less time handling radioactive materialtime handling radioactive material

DistanceDistance

Inverse square law: radiation Inverse square law: radiation exposure is inversely proportional to exposure is inversely proportional to the square of the distancethe square of the distance

DistanceDistance

Maximize your distance from Maximize your distance from radiation-producing machines and radiation-producing machines and radioactive materials or patientsradioactive materials or patients

Use tongs or other tools to handle Use tongs or other tools to handle radioactive sourcesradioactive sources

Move radioactive materials using a Move radioactive materials using a cart or portable lead “pig”cart or portable lead “pig”

ShieldingShielding

Use the right kind of shielding for the Use the right kind of shielding for the radiation in questionradiation in question Beta radiation: PlexiglasBeta radiation: Plexiglas Gamma and x-ray: Lead or other high-Gamma and x-ray: Lead or other high-

density materialdensity material Use sufficient shielding for the taskUse sufficient shielding for the task

ShieldingShielding

Engineering controls: leaded walls, Engineering controls: leaded walls, windows, movable barriers, bricks, windows, movable barriers, bricks, shipping and storage containers shipping and storage containers

PPE: Lead aprons, thyroid collars, PPE: Lead aprons, thyroid collars, and glasses for radiation-producing and glasses for radiation-producing equipmentequipment

ContainmentContainment

Engineering controls: Sealed sources, Engineering controls: Sealed sources, syringe caps, ventilation syringe caps, ventilation

PPE: Disposable gloves, lab coats, PPE: Disposable gloves, lab coats, isolation gowns, booties, goggles, isolation gowns, booties, goggles, face shields, coveralls, respiratorsface shields, coveralls, respirators

Routine contamination monitoring is Routine contamination monitoring is essential to verify proper essential to verify proper containment of radioactive materialscontainment of radioactive materials

Annual Occupational LimitsAnnual Occupational Limits

5000 mrem whole body5000 mrem whole body

15,000 mrem to lens of eye15,000 mrem to lens of eye

50,000 mrem to extremities50,000 mrem to extremities

Set by federal government based Set by federal government based on advice from scientific on advice from scientific committeescommittees

Are these limits safe?Are these limits safe?

The annual radiation limits have been The annual radiation limits have been established to ensure that the long-established to ensure that the long-term risks of radiation exposure are term risks of radiation exposure are minimized. There has been no minimized. There has been no evidence that occupational doses evidence that occupational doses within these limits pose any risk. Due within these limits pose any risk. Due to potential uncertainties in dose to potential uncertainties in dose measurement, the limits are set measurement, the limits are set conservatively.conservatively.

Other Dose LimitsOther Dose Limits

Members of public limited to 100 Members of public limited to 100 mrem per year from licensed mrem per year from licensed activities, 500 mrem per year from activities, 500 mrem per year from exposure to Nuclear Medicine therapy exposure to Nuclear Medicine therapy patientspatients

Employees under 18 limited to 10% of Employees under 18 limited to 10% of permissible adult dose limit (500 permissible adult dose limit (500 mrem annually)mrem annually)

Declared Pregnant WorkersDeclared Pregnant Workers

500 mrem/term limit to fetus (50 500 mrem/term limit to fetus (50 mrem/month)mrem/month)

Limit is extremely conservative Limit is extremely conservative with respect to riskwith respect to risk

Contact supervisor and Radiation Contact supervisor and Radiation Safety Officer to declare pregnancySafety Officer to declare pregnancy

Monthly fetal badge assignedMonthly fetal badge assigned

Who gets radiation badges?Who gets radiation badges?

Radiation badges are required for Radiation badges are required for workers who are likely to receive workers who are likely to receive more than 10% of the annual more than 10% of the annual occupational radiation limits. occupational radiation limits.

In practice, almost everyone who In practice, almost everyone who routinely works with radioactive routinely works with radioactive materials or radiation-producing materials or radiation-producing machines gets one or more machines gets one or more badges.badges.

How do I request a badge?How do I request a badge?

Ask your supervisor or the Radiation Ask your supervisor or the Radiation Safety Officer for a Personnel History Safety Officer for a Personnel History Form. You may also find the form Form. You may also find the form onlineonline..

Radiation Safety Training is required Radiation Safety Training is required to get a badge. Please ask your to get a badge. Please ask your supervisor or the RSO. Training may supervisor or the RSO. Training may be provided as an orientation packet, be provided as an orientation packet, an inservice, or online.an inservice, or online.

DosimetryDosimetry

Wear chest badge Wear chest badge underunder lead lead apron on chestapron on chest

Wear collar badge Wear collar badge outsideoutside lead lead apronapron

Extremity dosimetry (rings and Extremity dosimetry (rings and wrist badges) must conform to wrist badges) must conform to Infection Control requirementsInfection Control requirements

Proper Care of BadgesProper Care of Badges

Actually take them out of the Actually take them out of the package and wear thempackage and wear them

Take care not to reverse chest and Take care not to reverse chest and collar badgescollar badges

Do not leave badges on your apron Do not leave badges on your apron or in the suiteor in the suite

Exchange badges promptly at the Exchange badges promptly at the beginning of each month or pay $20beginning of each month or pay $20

How does the badge work?How does the badge work?

The Luxel dosimeter has a thin strip of The Luxel dosimeter has a thin strip of specially formulated aluminum oxide (Alspecially formulated aluminum oxide (Al22OO33) ) crystalline material. Filters of various thickness crystalline material. Filters of various thickness simulate radiation doses to different tissues. simulate radiation doses to different tissues. During analysis, the strip is stimulated with During analysis, the strip is stimulated with laser light, causing it to luminesce in proportion laser light, causing it to luminesce in proportion to the amount of radiation exposure.to the amount of radiation exposure.

Annual Occupational LimitsAnnual Occupational Limits

5000 mrem whole body5000 mrem whole body

15,000 mrem to lens of eye15,000 mrem to lens of eye

50,000 mrem to extremities50,000 mrem to extremities

Set by federal government based Set by federal government based on advice from scientific on advice from scientific committeescommittees

Other Dose LimitsOther Dose Limits

Members of public limited to 100 Members of public limited to 100 mrem per year from licensed mrem per year from licensed activities, 500 mrem per year from activities, 500 mrem per year from exposure to Nuclear Medicine therapy exposure to Nuclear Medicine therapy patientspatients

Employees under 18 limited to 10% of Employees under 18 limited to 10% of permissible adult dose limit (500 permissible adult dose limit (500 mrem annually)mrem annually)

Dosimetry ReportsDosimetry Reports

Dosimetry reports provided monthly Dosimetry reports provided monthly to departmental contactto departmental contact

Emory maintains permanent record, Emory maintains permanent record, department maintains for 3 yearsdepartment maintains for 3 years

Review and initial dosimetry reportsReview and initial dosimetry reports Report dosimetry problems to Report dosimetry problems to

supervisor or Radiation Safety Officersupervisor or Radiation Safety Officer

So, how do I read one of these things?So, how do I read one of these things?

Your name and participant number are listed in the first column. The date of the badges on the report is shown above.

Your name and participant number are listed in the first column. The date of the badges on the report is shown above.

The badge types on the report are listed here. Most Radiology workers have chest and collar badges.

The badge types on the report are listed here. Most Radiology workers have chest and collar badges.

The first number is the deep dose, the dose to the whole body from penetrating radiation (1 cm tissue depth)

The first number is the deep dose, the dose to the whole body from penetrating radiation (1 cm tissue depth)

The next number is the eye dose, the dose to the lens of the eye (0.3 cm tissue depth)

The next number is the eye dose, the dose to the lens of the eye (0.3 cm tissue depth)

The last number is the shallow dose, the dose to the dermal layer (0.007 cm tissue depth)

The last number is the shallow dose, the dose to the dermal layer (0.007 cm tissue depth)

The report also has quarterly, annual, and lifetime accumulated totals.The report also has quarterly, annual, and lifetime accumulated totals.

Dose DeterminationDose Determination

For workers with chest and collar For workers with chest and collar badges, assigned dose is a badges, assigned dose is a combination of readings:combination of readings: Whole body dose from a combination Whole body dose from a combination

of chest and collar badgesof chest and collar badges Eye dose from lens-equivalent area of Eye dose from lens-equivalent area of

collar badgecollar badge Shallow dose from skin-equivalent Shallow dose from skin-equivalent

area of collar badgearea of collar badge

Quarterly ALARA ReportsQuarterly ALARA Reports

Workers exceeding the doses on the Workers exceeding the doses on the following table are added to the following table are added to the ALARA reportALARA report

ALARA Level 2 doses are investigated ALARA Level 2 doses are investigated by the Radiation Safety Officerby the Radiation Safety Officer

Work activity may be restricted if Work activity may be restricted if corrective actions not takencorrective actions not taken

Quarterly ALARA LevelsQuarterly ALARA Levels

DoseDose Level 1Level 1 Level 2Level 2

Whole BodyWhole Body 125 mrem125 mrem 375 mrem375 mrem

CollarCollar 400 mrem400 mrem 1200 mrem1200 mrem

Lens of EyeLens of Eye 375 mrem375 mrem 1125 mrem1125 mrem

SkinSkin 1250 mrem1250 mrem 3750 mrem3750 mrem

ExtremitiesExtremities 1250 mrem1250 mrem 3750 mrem3750 mrem

What are the effects of high What are the effects of high doses of radiation?doses of radiation?

Acute radiation exposure, however rare, may Acute radiation exposure, however rare, may result in severe clinical effects or even death:result in severe clinical effects or even death: Exposures of minutes to hours while handling Exposures of minutes to hours while handling

highly radioactive sourceshighly radioactive sources Laboratory and manufacturing accidentsLaboratory and manufacturing accidents Intentional and accidental high medical dosesIntentional and accidental high medical doses

Radiation controls are in place to ensure that Radiation controls are in place to ensure that these kinds of exposures do not happen!these kinds of exposures do not happen!

Category of EffectsCategory of Effects

DeterministicDeterministic effects occur with acute effects occur with acute doses and result from cell deathdoses and result from cell death Characterized by threshold dose (below a given Characterized by threshold dose (below a given

dose, no effect)dose, no effect) StochasticStochastic effects may occur at chronic effects may occur at chronic

dosesdoses Affects the probability of all-or-none Affects the probability of all-or-none

phenomena such as carcinogenesisphenomena such as carcinogenesis Ill-defined threshold doseIll-defined threshold dose

Acute Radiation SyndromeAcute Radiation Syndrome

Follows a predictable course over a Follows a predictable course over a period of timeperiod of time

Characterized by the development of Characterized by the development of signs and symptomssigns and symptoms

Onset time of symptoms indicates Onset time of symptoms indicates dosedose

Severity of effect increases as dose Severity of effect increases as dose increasesincreases

ARS SyndromesARS Syndromes

Bone marrow syndromeBone marrow syndrome (a.k.a. hematopoietic (a.k.a. hematopoietic syndrome)syndrome) Full syndrome: between 0.7 and 10 GyFull syndrome: between 0.7 and 10 Gy Milder symptoms may occur as low as 0.3 GyMilder symptoms may occur as low as 0.3 Gy

Gastrointestinal (GI) syndromeGastrointestinal (GI) syndrome Full syndrome: >10 GyFull syndrome: >10 Gy Milder symptoms may occur as low as 6 GyMilder symptoms may occur as low as 6 Gy

Cardiovascular (CV)/ Central Nervous Cardiovascular (CV)/ Central Nervous System (CNS) syndromeSystem (CNS) syndrome Full syndrome: >50 GyFull syndrome: >50 Gy Some symptoms may occur as low as 20 GySome symptoms may occur as low as 20 Gy

Bone marrow syndrome Bone marrow syndrome

The survival rate of patients decreases The survival rate of patients decreases with increasing dosewith increasing dose

Characterized by damage to cells that Characterized by damage to cells that divide at the most rapid pace (such as divide at the most rapid pace (such as bone marrow, the spleen and lymphatic bone marrow, the spleen and lymphatic tissue)tissue)

The primary cause of death is the The primary cause of death is the destruction of the bone marrow, resulting destruction of the bone marrow, resulting in infection and hemorrhagein infection and hemorrhage

Gastrointestinal (GI) Gastrointestinal (GI) syndromesyndrome

Survival is extremely unlikely with Survival is extremely unlikely with this syndromethis syndrome

Destructive and irreparable changes Destructive and irreparable changes in the GI tract and bone marrow in the GI tract and bone marrow usually cause infection, dehydration, usually cause infection, dehydration, and electrolyte imbalanceand electrolyte imbalance

Death usually occurs within 2 weeksDeath usually occurs within 2 weeks

Cardiovascular (CV) / Central Cardiovascular (CV) / Central Nervous System (CNS) Nervous System (CNS)

syndromesyndrome Death typically occurs within 3 daysDeath typically occurs within 3 days Death likely is due to collapse of the Death likely is due to collapse of the

circulatory system as well as circulatory system as well as increased pressure in the confining increased pressure in the confining cranial vault as the result of cranial vault as the result of increased fluid content caused by increased fluid content caused by edema, vasculitis, and meningitis. edema, vasculitis, and meningitis.

Four Stages of ARSFour Stages of ARS

Prodromal stage (N-V-D stage): Classic Prodromal stage (N-V-D stage): Classic symptoms are nausea, vomiting, as well as symptoms are nausea, vomiting, as well as anorexia and possibly diarrhea, which occur anorexia and possibly diarrhea, which occur from minutes to days following exposure. from minutes to days following exposure. The symptoms may last (episodically) for The symptoms may last (episodically) for minutes up to several days.minutes up to several days.

Latent stage: Patient looks and feels Latent stage: Patient looks and feels generally healthy for a few hours or even up generally healthy for a few hours or even up to a few weeks.to a few weeks.

Four Stages of ARSFour Stages of ARS

Manifest illness stage: Symptoms depend Manifest illness stage: Symptoms depend on the specific syndrome and last from on the specific syndrome and last from hours up to several months.hours up to several months.

Recovery or death: Most patients who do Recovery or death: Most patients who do not recover will die within several months not recover will die within several months of exposure. The recovery process lasts of exposure. The recovery process lasts from several weeks up to two years.from several weeks up to two years.

Effects on Embryo / FetusEffects on Embryo / Fetus

High acute doses may cause death or High acute doses may cause death or abnormalitiesabnormalities

Large doses between 4 – 11 weeks can Large doses between 4 – 11 weeks can cause severe abnormalitiescause severe abnormalities

Doses as low as 25 rad may cause defectsDoses as low as 25 rad may cause defects Doses less than 10 rad generally Doses less than 10 rad generally

considered not to increase riskconsidered not to increase risk

Patients and PregnancyPatients and Pregnancy

Mandatory patient pregnancy testing for Mandatory patient pregnancy testing for high dose procedureshigh dose procedures

Screening permitted for low dose Screening permitted for low dose diagnostic proceduresdiagnostic procedures

Report cases of fetal exposure to Report cases of fetal exposure to supervisor and Radiation Safety Officer supervisor and Radiation Safety Officer IMMEDIATELYIMMEDIATELY

RSO will determine fetal dose and report RSO will determine fetal dose and report to patient’s physicianto patient’s physician

Cutaneous Radiation Syndrome Cutaneous Radiation Syndrome (CRS)(CRS)

Recently introduced to describe the Recently introduced to describe the complex pathological syndrome that complex pathological syndrome that results from acute radiation exposure results from acute radiation exposure to the skin.to the skin.

It is possible to receive a damaging It is possible to receive a damaging dose to the skin without symptoms of dose to the skin without symptoms of ARS, especially with acute exposures ARS, especially with acute exposures to beta radiation or X-rays.to beta radiation or X-rays.

Cutaneous Radiation Syndrome Cutaneous Radiation Syndrome (CRS)(CRS)

Cause of syndrome is radiation damage to Cause of syndrome is radiation damage to basal cell layer of the skinbasal cell layer of the skin

Characterized by inflammation, erythema, Characterized by inflammation, erythema, epilation, and/or dry or moist desquamationepilation, and/or dry or moist desquamation

Within a few hours after irradiation, a Within a few hours after irradiation, a transient and inconsistent erythema transient and inconsistent erythema (associated with itching) can occur(associated with itching) can occur

A latent phase may occur and last from a A latent phase may occur and last from a few days up to several weeks, when few days up to several weeks, when intense reddening, blistering, and intense reddening, blistering, and ulceration of the irradiated site are visibleulceration of the irradiated site are visible

Cutaneous Radiation Syndrome Cutaneous Radiation Syndrome (CRS)(CRS)

In most cases, healing occurs by In most cases, healing occurs by regenerative means; however, very regenerative means; however, very large skin doses can cause permanent large skin doses can cause permanent hair loss, damaged sebaceous and hair loss, damaged sebaceous and sweat glands, atrophy, fibrosis, sweat glands, atrophy, fibrosis, decreased or increased skin decreased or increased skin pigmentation, and ulceration or pigmentation, and ulceration or necrosis of the exposed tissue. necrosis of the exposed tissue.

SKIN EFFECTSKIN EFFECT Single-Dose Single-Dose Threshold (Gy)Threshold (Gy)

OnsetOnset

Early transient erythemaEarly transient erythema 22 HoursHours

Main ErythemaMain Erythema 66 ~10 d~10 d

Temporary epilationTemporary epilation 33 ~3 wk~3 wk

Permanent epilationPermanent epilation 77 ~3 wk~3 wk

Dry desquamationDry desquamation 1414 ~4 wk~4 wk

Moist desquamationMoist desquamation 1818 ~4 wk~4 wk

Secondary ulcerationSecondary ulceration 2424 >6 wk>6 wk

Late erythemaLate erythema 1515 ~6 – 10 wk~6 – 10 wk

Ischemic dermal necrosisIschemic dermal necrosis 1818 >10 wk>10 wk

Dermal atrophy (1Dermal atrophy (1stst phase) phase) 1010 >14 wk>14 wk

Dermal atrophy (2Dermal atrophy (2ndnd phase) phase) 1010 >1 yr>1 yr

Induration (Invasive Fibrosis)Induration (Invasive Fibrosis) 1010 >1 yr>1 yr

TelangiectasiaTelangiectasia 1010 >1 yr>1 yr

d: day(s); wk: week(s); yr: year(s)

How much radiation does it take to injure skin?

4 months after

procedures7 months 9 months

22 months 23 months

Three TIPS procedures in 1 week in type II diabetic. Total procedure time 13 - 16 hours. Three weeks later noticed 13-cm x 17-cm mottled oval discoloration on back. Initially diagnosed as strep infection, then as herpes I, then as allergic reaction to oral diabetic medications. Diagnosis of radiodermatitis obtained ten months after procedure!

Several months after

third angioplasty

5 months 22 months

At 3 wks

At 6.5 mos

Surgical flap

Following ablation procedure with arm in beam near port and separator cone removed. About 20

minutes of fluoroscopy.

Stochastic EffectsStochastic Effects

The effects of low levels of radiation are The effects of low levels of radiation are more difficult to determine because the more difficult to determine because the deterministic effects described above do deterministic effects described above do not occur at these levels.not occur at these levels.

Studies of people who have received high Studies of people who have received high doses have shown a link between radiation doses have shown a link between radiation dose and some delayed, or latent effects, dose and some delayed, or latent effects, including some forms of cancer and including some forms of cancer and genetic effects.genetic effects.

Stochastic EffectsStochastic Effects

To estimate the risks associated with To estimate the risks associated with low or chronic exposure, we create a low or chronic exposure, we create a model of the risk of occurrence of model of the risk of occurrence of cancer at high doses to the risk of cancer at high doses to the risk of cancer at low doses, usually assuming cancer at low doses, usually assuming no threshold. This type of risk model is no threshold. This type of risk model is called called stochasticstochastic. The risk of a clinical . The risk of a clinical effect increases with the dose, but the effect increases with the dose, but the effect is the same.effect is the same.

Stochastic EffectsStochastic Effects

This scaling or extrapolation is generally This scaling or extrapolation is generally considered to be a conservative considered to be a conservative approach (may over-estimate the risk) approach (may over-estimate the risk) to estimating low-dose risks.to estimating low-dose risks.

The risk of certain effects, including The risk of certain effects, including cancer, may be cumulative in patients cancer, may be cumulative in patients with repeated examinations and higher with repeated examinations and higher in younger patients.in younger patients.

Estimated Days of Life Expectancy Lost From Various Risk Estimated Days of Life Expectancy Lost From Various Risk FactorsFactors

Industry Type or ActivityIndustry Type or Activity Estimated Days of Life Expectancy Estimated Days of Life Expectancy LostLost

Smoking 20 cigarettes a daySmoking 20 cigarettes a day 2370 (6.5 years)2370 (6.5 years)

Overweight by 20%Overweight by 20% 985 (2.7 years)985 (2.7 years)

Mining and QuarryingMining and Quarrying 328328

ConstructionConstruction 302302

AgricultureAgriculture 277277

GovernmentGovernment 5555

ManufacturingManufacturing 4343

Radiation - 340 mrem/yr for 30 Radiation - 340 mrem/yr for 30 yearsyears

4949

Radiation - 100 mrem/yr for 70 Radiation - 100 mrem/yr for 70 yearsyears

3434

Ionizing Radiation at EUHIonizing Radiation at EUH

RadiographyRadiography FluoroscopyFluoroscopy Computed Tomography (CT)Computed Tomography (CT) Nuclear MedicineNuclear Medicine

DiagnosticDiagnostic TherapeuticTherapeutic

Radiation OncologyRadiation Oncology Blood IrradiationBlood Irradiation

How are X-rays produced?How are X-rays produced?

Electrons are fired at a target made Electrons are fired at a target made of a heavy material, like tungstenof a heavy material, like tungsten

The electrons are slowed down by The electrons are slowed down by the nuclei of the tungsten atomsthe nuclei of the tungsten atoms

Some of the electron energy is Some of the electron energy is converted to electromagnetic converted to electromagnetic radiation (x-rays)radiation (x-rays)

X-rays

High VoltageSupply

FilamentCurrentSupply

electrons

Glass envelopeTube housing and collimator

Tungstenfilament

TungstenTarget

Diagnostic X-ray TechniquesDiagnostic X-ray Techniques

RadiographsRadiographs

FluoroscopyFluoroscopy

Computed Tomography (CT)Computed Tomography (CT)

How do I reduce my exposure?How do I reduce my exposure?

Observe the following precautions:Observe the following precautions:

Maximize your distance from Maximize your distance from radiation producing machines radiation producing machines whenever practicalwhenever practical

Do not be in the suite longer than Do not be in the suite longer than necessarynecessary

Utilize available shieldingUtilize available shielding

Use Available ShieldingUse Available Shielding

Leaded Goggles, if necessary

Thyroid Shield

Badges

Lead vest & apron

Wear dosimetry!

Use Available ShieldingUse Available Shielding

Adjustable Adjustable head/neck shieldshead/neck shields

RADPAD patient RADPAD patient drapesdrapes

Leaded acrylic Leaded acrylic barriers and barriers and windowswindows

DistanceDistance

Know room geometryKnow room geometry NEVER PUT UNPROTECTED HANDS NEVER PUT UNPROTECTED HANDS

IN BEAMIN BEAM

72 mR/hr 21 mR/hr (1) (2) (3) (4) (5) 106 mR/hr 32 mR/hr 3 mR/hr 

1. 20cm from scattering object2. 30 cm3. 40 cm4. 50 cm5. 1 m

Keep Image Intensifier Close Keep Image Intensifier Close to Patientto Patient

Collimate to the Area of Collimate to the Area of InterestInterest

Don’t catch the edge Don’t catch the edge of the patient.of the patient.

Keep X-Ray Tube Below PatientKeep X-Ray Tube Below Patient

The patient is the source of the scattered radiation in the x-ray suite.

The spacer provides a minimum safe distance to the patient’s skin from the x-ray tube.

Reduce Magnification when Reduce Magnification when possiblepossible

Be Aware of Patient ThicknessBe Aware of Patient Thickness

When using When using automatic automatic brightness, larger brightness, larger patients will have a patients will have a higher radiation higher radiation exposure for the exposure for the same image quality same image quality as a thinner patient. as a thinner patient. Avoid oblique angles Avoid oblique angles when possible.when possible.

100 cm80 cm

Dose rate: 20 – 40 mGyt/min

Thick Oblique vs Thin PA geometryThick Oblique vs Thin PA geometry

100 cm

50 cm

Dose rate: ~250 mGyt/min

40 cm

Operator’s ResponsibilitiesOperator’s Responsibilities

Notifying the RSO when there is a Notifying the RSO when there is a new machine or any change in setupnew machine or any change in setup

Keeping exposures to himself & staff Keeping exposures to himself & staff ALARAALARA

Clearing the area of all nonessential Clearing the area of all nonessential personnelpersonnel

Operator’s ResponsibilitiesOperator’s Responsibilities

Observing any restrictionsObserving any restrictions Using minimum exposure factorsUsing minimum exposure factors Notifying your supervisor and the Notifying your supervisor and the

RSO immediately of any accidental RSO immediately of any accidental exposure to radiationexposure to radiation

FDA RecommendationsFDA Recommendations

Establish standard procedures and Establish standard procedures and protocolsprotocols

Determine dose rates for specific systemsDetermine dose rates for specific systems Assess each protocol for the potential for Assess each protocol for the potential for

radiation injury to the patientradiation injury to the patient Modify protocols to minimize cumulative Modify protocols to minimize cumulative

absorbed dose to any skin areaabsorbed dose to any skin area Appropriate training for all operatorsAppropriate training for all operators

After the ProcedureAfter the Procedure

Record fluoro time and projection in Record fluoro time and projection in patient chart, especially for patient chart, especially for interventional procedures with more interventional procedures with more than 30 minutes of beam-on timethan 30 minutes of beam-on time

Indicate in which room procedure Indicate in which room procedure occurredoccurred

Record any additional information on Record any additional information on radiation outputradiation output