Radiation characteristics and Protection (2nd part of DANB RHS outline)

What does kVp control?

contrast of xray beam

What does exposure time affect?

number of x-rays produced and darkness of the image

What effect does dense tissue have on an X-ray?

It blocks X-rays, creating lighter areas

What does higher kVp mean?

More energy and better penetration

What affects beam intensity?

kVp, mA, time, and distance

Why is understanding radiation characteristics important?

It helps produce quality images and protect patients

What's the difference between radiopaque and Radiolucent?

Radiopaque = white areas (like metal or bone).

Radiolucent = dark areas (like soft tissue or air)

What is the function of the anode?

Electrons hit it to produce X-rays

What is characteristic radiation?

a form of radiation originating from an atom following removal of an electron or excitation of an atom

What can happen when X-rays hit the body?

Absorbed, scattered, or pass through

What is primary radiation? And what's another word?

The main X-ray beam from the tubehead & Xray Beam

What is secondary radiation?

X-rays that bounce off matter after the primary beam hits

Q: Is secondary radiation stronger or weaker than primary?

Weaker

When is secondary radiation created?

When primary beam interacts with matter

What direction does secondary radiation travel?

In all directions—scattered

What does secondary radiation increase?

Radiation exposure

Name two highly radiosensitive tissues.

Bone marrow and reproductive cells

What kind of cells are least sensitive to radiation?

Muscle and nerve cells and brain cells

Is it true that radiation cause long-term cell damage?

Yes

What causes long-term radiation damage?

Cumulative low doses over time

Q: When do long-term effects appear?

Months or years after repeated low exposure

What are the two types of biological radiation effects?

Short-term and long-term effect

Q: When do short-term effects happen?

Soon after high radiation exposure

What is an example of a long-term effect?

Cancer or genetic mutations

What determines radiation effect on tissue?

Dose, duration, and frequency

Difference between stochastic effect?

What is a stochastic effect?

A: A random, long-term effect like cancer.

Q: What is a non-stochastic effect?

A: A predictable short-term effect, like skin redness

What is the latent period and what happens?

The time between radiation exposure and visible effects. And Cellular changes begin but no symptoms are seen

What is the injury period and what happens

When symptoms or damage appear. Follows the latent period. and Cell death, mutation, or loss of function

Recovery period definition

Time when cells may repair or recover

What's Exposure?

Unit: Roentgen (R) or Coulombs/kg (C/kg)

How much radiation is in the air.

What's Absorbed Dose

• Unit: Rad or Gray (Gy)

How much radiation the body actually absorbs.

What's Dose Equivalent

• Unit: Rem or Sievert (Sv)

Absorbed dose adjusted for the type of radiation (some types are more damaging).

What's Effective Dose

• Unit: Sievert (Sv)

Risk to the whole body, based on the tissue exposed.

What is the MPD for the general public per year?

0.1 rem or 1 mSv.

What is the MPD for a pregnant worker during pregnancy?

A: 0.5 rem or 5 mSv

A: 0.5 rem or 5 mSv

How do workers stay below MPD?

Use time, distance, and shielding

What is absorbed dose?

The energy from radiation absorbed by tissue

What is the unit for absorbed dose?

Gray (Gy) or rad

What is equivalent dose?

Absorbed dose adjusted for the type of radiation

What is the unit for equivalent dose?

Sievert (Sv) or rem

What is effective dose ?

Radiation risk adjusted for tissue sensitivity

What unit is used for effective dose?

Sievert (Sv)

Why is equivalent dose important?

Some radiation types cause more damage

Why is effective dose used in dental radiography?

To estimate the overall patient risk

Which dose is affected by type of tissue exposed?

Effective dose

Which dose is affected by type of radiation?

Equivalent dose

What does ALARA stand for?

As Low As Reasonably Achievable

Q: Where should the operator stand during exposure?

6 feet away, 90-135° from the beam

What type of radiation do barriers block?

Scatter radiation

What law explains why distance reduces radiation exposure?

Inverse square law

What shape of collimation reduces patient exposure best?

Rectangular

What kind of exposure settings should be used?

Lowest possible for a clear image

Should X-rays be taken at every appointment?

No, only when really needed

Do children require more or fewer X-rays than adults?

Fewer

What should be considered before taking an X-ray?

Patient's age, risk, history, and symptoms

Who sets dental radiation safety guidelines in the U.S.?

ADA and FDA

What is a major cause of unnecessary radiation?

Taking X-rays without clinical need

What causes overexposure from the X-ray machine?

Incorrect settings (kVp, mA, time)

How does poor equipment maintenance affect exposure?

It can cause image errors, leading to retakes

What is the result of not using rectangular collimation?

Larger exposure area than needed

What's Inherent filtration?

built into the X-ray tube (like glass, oil, and housing)

What's Added filtration?

any filtration that occurs outside the tube and housing before the image receptor

Examples of inherent filtration?

Glass tube, oil, and tube housing

What's the purpose of filtration?

To protect the patient from extra radiation

What does added filtration do to beam quality?

Increases it

What kind of material is used for added filtration?

Aluminum

Two main types of shielding?

Structural and personal.

What is structural shielding?

Shielding built into walls or operator barriers.

What is personal shielding?

Lead aprons and thyroid collars

What material is most shielding made of?

LEAD

What's a lead apron used for?

To protect vital organs

What does collimation control and what's the purpose?

Size and shape of the X-ray beam and To reduce patient exposure and scatter radiation

What does a rectangular collimator match?

The size of the image receptor

What part of the X-ray unit collimates the beam?

The metal diaphragm inside the PID

Which PID gives off more scatter radiation?

Short round PID

How does a long PID reduce scatter?

It keeps the beam tighter and more focused

What's the typical length of a long PID?

16 inches

What's the typical length of a short PID?

8 inches

What does A beam alignment device do

Aligns the PID with the image receptor

Examples of beam alignment devices

Xcp Holders

What's the benefit of the aiming ring?

Guides PID for proper angulation

Why does size and age matter in radiation protection?

It affects how much radiation is needed

What must be adjusted for pediatric patients?

Exposure time and settings

What settings might you lower for kids?

Time, kVp, and mA

Which law does adjusting for age and size support?

Alara

Do large adults need higher or lower exposure?

Higher

How can you reassure patients?

Explain safety measures and low dose

What type of X-rays expose patients to less radiation?

Digital

What's one thing you can do before taking an X-ray?

Explain why it's needed

What is informed consent?

When a patient agrees after understanding the risks and benefits

What should you do if a patient refuses X-rays?

Explain the risks and document the refusal

Can you treat a patient without necessary X-rays?

No, it may affect diagnosis and care

What must be included in informed consent?

Risks, benefits, and alternatives

What's Class 4?

Anterior proximal with incisal edge. In between front teeth and includes the biting edge; Incisal edges

What are somatic effects of radiation?

Radiation effects that occur in the body of the person exposed, not passed to offspring

What are genetic effects of radiation?

Radiation effects that occur in reproductive cells and can be passed to future generations

Are somatic effects hereditary?

No but Genetic effects hereditary

What's magnification?

The tooth or structure looks bigger on the image than it really is🔎

What is Fixer Splash?

When fixer solution accidentally splash on the film before it's processed, causing white or light spots on the final image

What is Developer Splash?

When developer solution splashes on the film before regular processing, causing dark or black spots on the image