LECTURE 4 ~~~~ FROM NOTES

What is the radiation dose of a typical intraoral radiograph?

How much radiation does a complete cone-beam computed tomography (CBCT) scan of both jaws expose a patient to?

What radiation dose is associated with a cephalometric radiograph?

Which principle ensures that patients are only exposed to ionizing radiation when the benefits outweigh the risks?

What is the recommended radiation dose limit for non-classified workers?

What is the purpose of Diagnostic Reference Levels (DRL)?

What dose would a section of jaw radiograph with cone-beam computed tomography produce?

How does substituting periapical X-rays with CT scans affect population dose in the UK?

What is the primary measure of absorbed dose of radiation?

Which factor is NOT considered in the equivalent dose calculation?

Which type of dose is considered the gold standard for assessing radiation risk?

What is the risk of cancer induction for women following a dental radiograph?

Which tissue is identified as the most radiosensitive?

Which ionizing radiation type has the highest radiation weighting factor?

What is the average background radiation exposure in the UK, measured per year?

How is the effective dose calculated?

Intraoral Radiograph

Less than 2 uSv and ¼ of a day's background radiation
Examples: intraoral (periapical/bitewing) 2D radiograph - 2 uSv, DPT 2D radiograph - 20 uSv
Cone-beam CT scan 3D (section) - 40 uSv
Cone-beam CT scan 3D (all teeth in both jaws) - 80 uSv

Panoramic Radiograph

14-24 (20) uSv and 2-3 days of background radiation

Cephalometric Radiograph

Less than 6 uSv and 1 day of background radiation

Cone-Beam Computed Tomography (CBCT)

3D image, dose depends on how big the area you image is
Both Jaw radiograph = 84 uSv = 39 uSv = 2 panoramic radiographs

Radiation Concerns in Dental X-Rays

Cumulative effects of ionizing radiation
Biological Harm Potential: Even low doses can increase lifetime cancer risk
Professional Impact: Numerous cumulative population dose
Comparison of Techniques: Substituting periapical X-rays with CT scans would significantly increase the UK's cumulative population dose

International Commission on Radiographical Protection (ICRP)

Justification: Patient should only be exposed to ionizing radiation if benefits outweigh risks
Optimization: Use lowest dose possible (ALARP - as low as reasonably practicable)
Dose Limitation: (only applies to staff and public)
- Efforts made to reduce exposure to patients, also reduce exposure to dental staff
- Ensure no individual is exposed to high diagnostic or therapeutic purposes
- No dose limits for patients exposed for diagnostic or therapeutic purposes
- Dose limit: Classified Workers – 20mSv
- Dose limit: Non-classified Workers – 6mSv

Diagnostic Reference Levels (DRLs)

DLR is a dose level for typical examination on standard-sized patients
DLR is essentially a reference, recommended dose, for common X-ray examinations
Not normally exceeded without good reason
It can be set locally or with a medical physics expert or Public Health England

This quiz covers various types of dental radiographs, including intraoral, panoramic, cephalometric, and cone-beam CT scans. It discusses radiation doses, background radiation comparisons, and radiation concerns, as well as the potential biological harm of ionizing radiation. Test your knowledge of dental imaging and radiation safety practices.