Chapter 3 Chapter 3 Radiation SafetyRadiation Safety

Vet Tech InstituteVet Tech Institute

Radiation should be respected Radiation should be respected not Feared!not Feared!

Safety is Always important!Safety is Always important!

Stray Radiation Exposure is common, Stray Radiation Exposure is common, but can be limited.but can be limited.– All radiation equipment must meet state All radiation equipment must meet state

regulations (Department of Health). regulations (Department of Health).

Safe Operating Procedures Safe Operating Procedures Should Include:Should Include:

An adequate technique chart or An adequate technique chart or comparable systemcomparable system

Positioning aidsPositioning aids Protective clothing and other Protective Protective clothing and other Protective

BarriersBarriers Personnel dosimetry devicesPersonnel dosimetry devices Emergency Procedures for malfunctioning Emergency Procedures for malfunctioning

x-ray equipmentx-ray equipment Quality control measurements and Tests. Quality control measurements and Tests.

Hazards of Ionizing Hazards of Ionizing RadiationRadiation

All living cells are susceptible to All living cells are susceptible to ionizing radiation damage.ionizing radiation damage.

Affected cells may be damaged or Affected cells may be damaged or killed.killed.

Rapidly dividing cells are most Rapidly dividing cells are most sensitive to radiation.sensitive to radiation.

2 types of Biologic Damage can 2 types of Biologic Damage can Occur from over-exposure to Occur from over-exposure to

RadiationRadiation 1. Somatic Damage1. Somatic Damage

2. Genetic Damage2. Genetic Damage

Somatic DamageSomatic Damage

Damage to the body that becomes Damage to the body that becomes manifest within the lifetime of the manifest within the lifetime of the recipient.recipient.– Skin issuesSkin issues– CancerCancer– CataractsCataracts– Etc.Etc.

Genetic DamageGenetic Damage

Occurs when the genes of reproductive Occurs when the genes of reproductive cells. cells.

Damages DNA.Damages DNA. Can result in gene mutation.Can result in gene mutation. Not detectable until future generations.Not detectable until future generations. May be lethal or only a visible anomaly.May be lethal or only a visible anomaly. May be latent for generations.May be latent for generations.

Images of Radiation Images of Radiation DamageDamage

Death by x-ray?Death by x-ray?

Mortality/Death is caused by exposure to Mortality/Death is caused by exposure to extremely high levels of radiation.extremely high levels of radiation.– Death has occurred with single dose to 300 Death has occurred with single dose to 300

rads.rads.

Should never occur to a vet tech!!!!Should never occur to a vet tech!!!!

Technically, no amount of radiation is non-Technically, no amount of radiation is non-damaging. Even under best conditions, damaging. Even under best conditions, some exposure will occur.some exposure will occur.

Maximum Permissible Dose Maximum Permissible Dose (MPD)(MPD)

Maximum dose of radiation that a Maximum dose of radiation that a person may receive in a given period.person may receive in a given period.– No one under 18 is allowed to enter No one under 18 is allowed to enter

radiographic suite unless ordered by a radiographic suite unless ordered by a medical doctor.medical doctor.

– Occupationally exposed can receive up to Occupationally exposed can receive up to 0.05 Sv (Sieverts) per year.0.05 Sv (Sieverts) per year.

– Non-occupationally exposed can receive Non-occupationally exposed can receive up to 0.005 Sv a year. up to 0.005 Sv a year.

A.L.A.R.A.A.L.A.R.A.

Stands for As Low As Reasonably AchievableStands for As Low As Reasonably Achievable Principle based on the knowledge that there Principle based on the knowledge that there

is no threshold dose for radiation injury, that is no threshold dose for radiation injury, that is all radiation exposure entails some is all radiation exposure entails some degree of riskdegree of risk

All individuals working around radiation All individuals working around radiation must consider this concept and act on it by must consider this concept and act on it by observing all safety procedures and observing all safety procedures and cautions, thus exposing themselves to the cautions, thus exposing themselves to the least amount of radiation possibleleast amount of radiation possible

Radiation Exposure UnitsRadiation Exposure Units

2 Categories2 Categories– 1. Absorbed Dose1. Absorbed Dose

The quantity of energy imparted by ionizing radiation The quantity of energy imparted by ionizing radiation to matter per unit mass of the matter. Unit is the gray to matter per unit mass of the matter. Unit is the gray (Gy). (Gy).

– 1 Gy= 100 rad1 Gy= 100 rad

(The amount of radiation energy absorbed by tissue)(The amount of radiation energy absorbed by tissue)

– 2. Dose Equivalent2. Dose Equivalent Quantity obtained by multiplying the absorbed dose in Quantity obtained by multiplying the absorbed dose in

tissue by the quality factor. Unit is the Sievert (Sv).tissue by the quality factor. Unit is the Sievert (Sv).– 1 Sv=100 rems1 Sv=100 rems

(Measure of the amount of radiation that one receives)(Measure of the amount of radiation that one receives)

Patient ExposurePatient Exposure

Animal patients are just as Animal patients are just as susceptible to irradiation damage as susceptible to irradiation damage as humans.humans.

Shielding of the gonads of breeding Shielding of the gonads of breeding animals is recommended. animals is recommended.

Unnecessary and excessive Unnecessary and excessive radiography should always be radiography should always be avoided for any patient in general. avoided for any patient in general.

Personnel Monitoring Personnel Monitoring DevicesDevices

Dosimetry-various methods used to Dosimetry-various methods used to measure radiation exposure to measure radiation exposure to personnel.personnel.– Types:Types:

Film BadgeFilm Badge Pocket Ionization ChamberPocket Ionization Chamber Thermoluminescent dosimeter (TLD)Thermoluminescent dosimeter (TLD)

Dosimeters- personal exposure Dosimeters- personal exposure monitoring devicesmonitoring devices

Identify these Monitoring Identify these Monitoring DevicesDevices

Practical Application of Practical Application of Radiation SafetyRadiation Safety

Personnel exposure is a result of:Personnel exposure is a result of:– 1. Exposure to the primary beam1. Exposure to the primary beam– 2. Exposure from secondary (scatter) radiation2. Exposure from secondary (scatter) radiation– 3. Exposure from “leakage” radiation from the 3. Exposure from “leakage” radiation from the

x-ray tube housingx-ray tube housing

IT IS THE RESPONSIBILITY OF THE INDIVIDUAL TO IT IS THE RESPONSIBILITY OF THE INDIVIDUAL TO ENSURE HIS OR HER OWN RADIATION ENSURE HIS OR HER OWN RADIATION PROTECTION AT THE TIME OF PROTECTION AT THE TIME OF EXPOSURE!!!!!!!!!!!!!!!!!!!!!!!!!!!!EXPOSURE!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Collimation, Collimation, Collimation, Collimation, CollimationCollimation

Collimator limits the primary beam Collimator limits the primary beam so that scatter or secondary radiation so that scatter or secondary radiation is reduced to the patient and to is reduced to the patient and to those assisting with the radiographic those assisting with the radiographic procedure. procedure.

FiltersFilters

States require filtration of primary States require filtration of primary beam.beam.– Composed of 2.5 mm aluminumComposed of 2.5 mm aluminum

Filter is located between the window Filter is located between the window of x-ray tube and the collimator.of x-ray tube and the collimator.– Eliminates less penetrating or “soft” x-Eliminates less penetrating or “soft” x-

rays.rays.

Secondary (Scatter) Secondary (Scatter) RadiationRadiation

Produced when primary beam Produced when primary beam interacts with objects in its path.interacts with objects in its path.

Amount and direction depends on the Amount and direction depends on the intensity of the beam, the composition intensity of the beam, the composition of the structure being radiographed, of the structure being radiographed, the kVp level, and the thickness of the the kVp level, and the thickness of the patient.patient.

Scatter can be produced in all Scatter can be produced in all directions but travels in straight lines.directions but travels in straight lines.

How to limit exposureHow to limit exposure

Personnel should be as far away from Personnel should be as far away from primary beam as possible.primary beam as possible.

If proper precautions are taken, then If proper precautions are taken, then no one should receive a significant no one should receive a significant amount of radiation.amount of radiation.

Chemical restraint.Chemical restraint. Mechanical restraint.Mechanical restraint.

Personal Protective Equipment Personal Protective Equipment (PPE)(PPE)

Lead apronsLead aprons Lead glovesLead gloves Thyroid ShieldsThyroid Shields Eye protectionEye protection

– Should have 0.5 mm lead equivalent in Should have 0.5 mm lead equivalent in aprons, gloves and shields.aprons, gloves and shields.

I see an ArtifactI see an Artifact

Artifacts- anything on radiograph Artifacts- anything on radiograph that should not be there.that should not be there.– Motion artifactsMotion artifacts– Cassette artifactsCassette artifacts– FINGERS!!FINGERS!!

Get it right the first time!!Get it right the first time!!

AVOID RE-TAKES!!!!!!!!!!!!!!!!!AVOID RE-TAKES!!!!!!!!!!!!!!!!!– Way to do this is to use technique charts Way to do this is to use technique charts

and measuring devices. and measuring devices. – Refer to pre-existing radiographs and Refer to pre-existing radiographs and

radiograph logs.radiograph logs.– This is cost effective and could save This is cost effective and could save

time, thus saving a life!time, thus saving a life!– National repeat rate for radiographs is 8 National repeat rate for radiographs is 8

%. Each repeat is another radiation %. Each repeat is another radiation dose to patient and technician.dose to patient and technician.

Maintenance of Protective Maintenance of Protective ApparelApparel

Proper care is essential to continued Proper care is essential to continued radiation safety.radiation safety.

Veterinary Radiography requires 0.5 Veterinary Radiography requires 0.5 mm of lead equivalent because mm of lead equivalent because restrainer is close to primary beam.restrainer is close to primary beam.

Aprons should be hung vertically or Aprons should be hung vertically or laid flat when not in use.laid flat when not in use.

Gloves should be placed on vertical Gloves should be placed on vertical holders.holders.

Visual inspection should be Visual inspection should be performed every time apparel is performed every time apparel is worn.worn.

Any tears or obvious problems Any tears or obvious problems should be investigated farther.should be investigated farther.

If defective, should be replaced or If defective, should be replaced or discarded. discarded.

Radiation Safety RulesRadiation Safety Rules

Remove all unnecessary personnel from Remove all unnecessary personnel from radiographic suite during exposure.radiographic suite during exposure.

No one under 18 allowed.No one under 18 allowed. No pregnant women allowed.No pregnant women allowed. Rotate personnel.Rotate personnel. Use mechanical restraints when possible.Use mechanical restraints when possible. Use chemical restraint when possible.Use chemical restraint when possible. Always wear PPE.Always wear PPE. Properly care for PPE.Properly care for PPE.

Never permit body to be within Never permit body to be within primary beam.primary beam.

Use collimation when possible.Use collimation when possible. Use filters.Use filters. Do not aim primary beam at Do not aim primary beam at

personnel or adjacent rooms.personnel or adjacent rooms. Never hand hold the x-ray tube.Never hand hold the x-ray tube. Wear badges.Wear badges.

Avoid re-takes.Avoid re-takes. Maintain chemicals.Maintain chemicals. Have machine services and Have machine services and

calibrated regularly.calibrated regularly. Keep exposure log.Keep exposure log. Adhere to safety codes of the state.Adhere to safety codes of the state. Have Patience.Have Patience.

http://www.youtube.com/watch?v=3u_8frR0IpE

http://www.youtube.com/watch?v=rvAJ_u3Q0Hw&feature=related