ch 4: radiation protection

patient protection

-X-radiation causes biologic changes in living cells; it adversely affects all living tissue

-Our goal is to minimize the amount of radiation received by the patient and maximize the benefits

patient protection techniques may be used _ ,_ , and _ the procedure to protect the patient

before, during, and after

ways to protect patient before exposure

-HH

-vitals

-prescribing dental radiographs

-proper equipment

prescribing dental radiographs

-Professional judgment is used to determine the number, type, and frequency of dental radiographs

-The ADA/FDA has published guidelines/recommendations

-Private practice office protocol

-Patient’s needs #1 determining factor

-No predetermined number or time intervals

proper equipment

-Use of equipment that complies with state and federal radiation guidelines will minimize the radiation a patient receives

-filtration (aluminum filters)

-collimation

-positioning indicating device

types of filtration

-inherent filtration

-added filtration

-total filtration

inherent filtration

-Takes place when the primary beam passes through the glass window of the x-ray tube, the insulating oil, and the tubehead seal

-Equivalent to approximately 0.5 to 1.0 mm. of aluminum

-It does not meet the standards regulated by state and federal law, so additional filtration is required

added filtration

-An aluminum disk is placed between the collimator and the tubehead seal to filter out longer wavelength, lower energy x-rays from the x-ray beam. Allowing? ↓ LW; ↑SW; ↑ energy

-Filtration results in a higher-energy and more penetrating useful beam

-Added in increments of .5 mm

total filtration

-the sum of inherent and added filtration

-regulated by state and federal law

machine operation at or below 70 kVp requires a minimum total of _____ aluminum filtration

1.5 mm

machines operating above 70 kVp requires a minimum total of ___ aluminum filtration

2.5mm

collimator

-restricts the size and shape of the x-ray beam

-reduces patient exposure

-made of lead

round collimator/diaphragm

-produces a cone-shaped beam that is 2.75 in diameter

-federal regulation requires max size beam to patient skin

rectangular collimator/diaphragm

produces a rectangular beam slightly larger than a #2 film

position-indicating device

-An extension of the x-ray tubehead used to direct the x-ray beam

-May be conical, rectangular, or round

conical PIDs

-no longer used in dentistry

-created the most scatter radiation

rectangular and round PIDs

-come in 8 or 16 in lengths

-they are open ended and lead lined

-the long PID produces the least divergence of the x-ray beam

ways to protect patient during exposure

-thyroid collar

-lead apron

-image receptors

-fast film

-film holding devices

-exposure factor selection

-proper technique

thyroid collar

-A flexible lead shield placed around the patient’s neck

-Protects the thyroid gland from scatter radiation

-May be separate or part of the lead apron

-Recommended for all intraoral films

-Not recommended for extraoral films

lead apron

-Placed over the patient’s chest and lap to protect the reproductive organs and blood forming tissues from scatter radiation

-Use is often a state law

-made of .25 mm of lead

image receptors

-The single most effective method of reducing a patient’s exposure to radiation

-Use of digital receptors can reduce up to 50% to 90%

fast film

when digital is not available this is your next most effective method

-20% reduction over E

-60% reduction over D

film holding devices

-Stabilizes the film position in the mouth and reduces the chance for movement

-Eliminates the need for the patient to hold the film in position with their finger, reducing unnecessary exposure

-RINN

exposure factor selection

-Adjustment of kVp, milliamperage, and time settings on the control panel to limit the amount of x-radiation exposure received by the patient

-On some units, the kilovolt peak and milliamperage are preset by the manufacturer and cannot be adjusted for ex the Nomad / Cocoon

proper technique

nondiagnostic films must be retaken, resulting in additional radiation exposure for the patient

ways to protect patient after exposure

-proper film handling

-proper film processing

proper film handling

artifacts caused by improper film handling result in nondiagnostic films

proper film processing

may require retakes, needlessly exposing patient to excess x-radiation

operator protection

protection guidelines and radiation monitoring

protection guidelines

the dental radiographer must avoid the primary beam

the protection guidelines include:

-distance recommendations

-position recommendations

-shielding recommendations

distance recommendations

-Maintain an adequate distance during exposure

-The dental radiographer must maintain a distance of at least 6 feet from the tubehead during an exposure

position recommendations

-Avoid the primary beam by

• Leaving the room

• Behind barrier

• Wall

• Standing either perpendicular or at a 90- to 135- degree angle to the beam

• The operator must never hold a film in a patient’s mouth or hold the tubehead during an exposure

shielding recommendations

-dental office design may include lead lined walls/ doors/ windows to protect operator from primary and scatter radiation

-may have a mirror to help monitor patient

types of radiation monitoring

-equipment monitoring

-personnel monitoring

equipment monitoring

dental x-ray machines must be monitored for leakage radiation

personnel monitoring

-a film badge can be work at waist level when taking radiographs

-it is mailed to the monitoring company once a month for evaluation

radiation exposure guidelines include:

-radiation safety legislation

-maximum permissible dose (MPD)

-cumulative occupational dose or maximum accumulated dose (MAD)

-ALARA concept

radiation safety legislation includes

-radiation control for health and safety act

-consumer-patient radiation health and safety act

radiation control for health and safety act

-1968

-standardized performance of x-ray equipment

consumer-patient radiation health and safety act

-1981

-address education and certification of persons using radiographic equipment

-every state has different laws

maximum permissible dose (MPD)

maximum dose equivalent that a body is permitted to receive in a specific period of time

MPD for occupationally exposed person

5.0 rem/ year or .05 Sv/year

MPD for non-occupationally exposed person

0.1 rem/year

MPD for occupationally exposed pregnant women during pregnancy months

.05 rems

cumulative occupational dose

-the dose accumulated over time

-a formula based in the occupational exposed worker’s age

= (N-18) x 5 rem/year

or

= (N-18) x 0.05 Sv/year

-age x 10 mSv

ALARA concept

-as low as reasonably achievable

-every possible method of reducing exposure to radiation should be employed

radiation protection and patient education

-what you say to the patient before, during, and after the procedure

• truth about protocols for protection

• early detection

• small amount of radiation

• safety measures are applied

• when radiographs are properly prescribed and exposed, the benefit of disease detection outweighs the risk of damage