Safety Flashcards
1
Q
Dosimetry Exposure
A
- Measure capacity of x rays to ionize air
- Unit: roentgen (R) = coulombs/kg
- Measures intensity of radiation field, NOT radiation absorbed
2
Q
Dosimetry Absorbed Dose
A
- Measure of total energy absorbed by any type of ionizing radiation per unit mass of matter
- Unit: gray (gy) = J/kg
- But doesnt distinguish the type of matter or radiation
- CHest radiograph differnt risk than full mouth examination
3
Q
Dosimetry Effective Dose
A
- Unit Sievert (Sv)
- Estimates risk in humans
- Considers relative effectiveness of different types of radiation and radiosensitivity of different tissues
- Calculated by differnt wighting factors of types of radiation and types of tissues
4
Q
Primary risk of dental radiography
A
- Cancer which is a stochastic dose
- there is no threshold no safe dose
- Less certainty with low dosage
5
Q
Linear non threshold hypothesis
A
- Widely accepted in radiation safety and protection
- Linear relationship between dose and risk of inducing a new cancer
- No threshold= no safe dose
6
Q
Reducing Dental Exposure
3 guiding principles in radiation protection
A
- Justification
- patient benefit vs risk
- Optimization
- Use every reasonable measure to reduce unnecesary exposure
- ALARA= As low as reasonably achievable
- Collimation, filters, reducing levels, faster film
- Dose limitation
- Limits for workers and public but NOT patients
7
Q
What organization determines radiograph guidelines and what are the 3 things they consider
A
- American Dental Association Council on Scientific Affairs
- Patient selection
- Conducting the examination protecting personnel
8
Q
kVp in mA settings
A
- Kilovoltage
- optimal 60-70 kVp
- mA
- set mA and time for optimal quality
- Usually kVp and mA are fixed and you just change time
9
Q
Protecting personner
Position and sitance rule
A
- Used when barrier is impossible
- Operator is at least 6 feet from patient at an angle of 90 to 135 degrees to the central ray of the xray beam
- Take advantage of inverse square law
- Most of scatter radiation sbsorbed by patient
10
Q
Exceptions to prescribing radiographs
A
- Interproximal caries
- high prevelance for disease
- Imposible to visually inspect
- Endodontically treated teeth
- Impossible to detect
11
Q
New patient Child with primary detention
A
- Selected PA/occlusal/bitewings if proximal surfaces cannot be visualized
- Patients without evidence of disease and with open contacts may not need xrays
12
Q
New Patient
Child with transitional detention
A
- Posterior bitewings with pano or selected PA
13
Q
New Patient
Adolescent with permanent detention
A
- Posterior bitewings with pano or selected periapicals
- Full mouth when patient has generalized disease or history of extensive dental treatment
14
Q
Recall Exam with increased caries risk
Adolescent/child
A
- Posterior bitewing at 6-12 month intervals if proximal surfaces cant be visualized or probed
15
Q
Recall exam on increased caries risk
Adult or partially edentulous
A
- Posterior bitewing exam at 6-18 month intervals
