Radiation Protection

What are the three components of inherent filtration?

Glass window of the x-ray tube, insulating oil, and tubehead seal.

What is added filtration?

Aluminum discs added to the x-ray tubehead to filter radiation.

How much filtration does each aluminum disc provide?

0.5 mm.

According to the lecture, what is the required total filtration for lower kVp machines?

1.5 mm aluminum equivalent.

According to the lecture, what is the required total filtration for higher kVp machines?

2.5 mm aluminum equivalent.

What does filtration remove from the x-ray beam?

Long-wavelength, low-energy x-rays.

What happens to the average penetrating power of the x-ray beam after filtration?

It increases.

What is collimation?

Restricting the size and shape of the x-ray beam.

What is a collimator made of?

A lead plate with an opening for the x-ray beam.

What is rectangular collimation?

A rectangular opening slightly larger than the image receptor.

What is circular collimation?

A round opening that produces a circular x-ray beam.

What is the diameter of a circular collimator according to the lecture?

2.75 inches.

Which collimator reduces unnecessary radiation exposure more effectively?

Rectangular collimator.

What are the three types of position-indicating devices (PIDs)?

Conical, rectangular, and round.

Why are conical PIDs no longer used?

They cause too much scattered radiation.

What are the two common PID lengths?

8 inches and 16 inches.

Which PID length is preferred?

16 inches (long PID).

Why is a long PID preferred?

It reduces beam divergence.

What is the purpose of a thyroid collar?

To protect the thyroid gland from radiation.

Why is a thyroid collar not used during panoramic radiographs?

It can interfere with the image.

What is the purpose of a lead apron

To shield the torso, reproductive organs, and blood-forming tissues.

What is the minimum lead equivalence of a protective apron according to the lecture?

Greater than 0.25 mm.

What is the most effective method of reducing patient radiation exposure according to the lecture?

Using faster film speed.

What two film speeds are mentioned in the lecture?

D-speed and F-speed.

How much faster is F-speed film than D-speed film?

60% faster.

How much can digital sensors reduce exposure time compared with film?

50–80%.

What six methods help protect patients from excess radiation during exposure?

Thyroid collar, lead apron, fast film or digital sensors, beam alignment devices, proper exposure settings, and proper technique.

What is the purpose of a beam alignment device?

To hold the receptor, allow paralleling, and align the PID correctly.

What kVp range minimizes patient exposure according to the lecture?

60–80 kVp.

What mA range is mentioned in the lecture?

6–8 mA.

Why is proper radiographic technique important?

It produces a diagnostic image the first time and prevents unnecessary retakes.

Why is proper film or sensor handling important?

To obtain diagnostic-quality images.

Why is proper film processing important?

To maintain diagnostic image quality.

Why is proper image storage important?

To preserve diagnostic images.

Why is proper mounting important?

To prevent errors and unnecessary retakes.

How far should an operator stand from the x-ray tubehead during exposure?

At least 6 feet away, or behind a protective barrier.

Where should an operator stand during x-ray exposure?

Behind a lead barrier or off to the side, outside the primary beam.

Should an operator ever stand in the path of the primary x-ray beam?

No.

Should an operator hold the receptor in the patient's mouth during exposure?

No, never.

Should an operator hold the tubehead during exposure?

No, never.

What three types of radiation are identified in the operator protection section?

Primary radiation, leakage radiation, and scattered radiation.

What is equipment monitoring?

Checking x-ray machines for radiation leakage through mandatory inspections.

What is personnel monitoring?

Monitoring the radiation exposure received by workers.

What device is used for personnel monitoring?

A dosimeter badge.

Are personnel monitoring badges commonly used according to the lecture?

No, not commonly.

What does ALARA stand for?

As Low As Reasonably Achievable.

What is the purpose of ALARA?

To keep radiation exposure as low as reasonably achievable for patients and workers.

What federal law standardized x-ray equipment?

Radiation Control for Health and Safety Act of 1968.

What does Indiana require for dental radiography operators according to the lecture?

Licensure.

What does MPD stand for?

Maximum Permissible Dose.

What is MPD?

The maximum yearly radiation dose a person may receive with little or no expected injury, according to the lecture.

Which organization defines MPD?

National Council on Radiation Protection and Measurements (NCRP).

What is the annual occupational MPD according to the lecture?

5 rem, 0.05 Sv, or 50 mSv.

What is the annual MPD for the general public according to the lecture?

0.1 rem, 0.001 Sv, or 1 mSv.

What is the monthly MPD during pregnancy according to the lecture?

0.05 rem, 0.0005 Sv, or 0.5 mSv.

What does MAD stand for?

Maximum Accumulated Dose.

What is the older formula for MAD?

(N − 18) × MPD.

What does N represent in the MAD formula?

The person's current age.

What does COD stand for?

Cumulative Occupational Dose.

What is the current COD formula according to the lecture?

Age × 10 mSv.

What is the COD for a 50-year-old hygienist?

500 mSv or 0.5 Sv.

What radiation protection steps should be taken BEFORE exposure?

Prescribe only necessary radiographs, use filtration, and use proper collimation.

What radiation protection steps should be taken DURING exposure?

Use patient shielding as taught, fast receptors, beam alignment devices, correct exposure settings, and proper technique.

What radiation protection steps should be taken AFTER exposure?

Properly handle, process, store, and mount radiographs to prevent unnecessary retakes.

How should dental professionals educate patients about radiation exposure?

Explain precautions, answer questions, acknowledge risks, and discuss benefits.

When should dental radiographs be prescribed?

Only when necessary based on the individual patient's needs.

Should radiographs be retaken just to improve a grade?

No.