5. Radiology

Question 1

T/F Radiographic screening for the purpose of detecting disease before clinical examination should be performed.

Answer 1

False, should NOT be performed

Question 2

T/F Dental radiation had deterministic effects

Answer 2

False, dental radiation has stochastic effects

Question 3

What are deterministic effects from radiation?

Answer 3

killing of cells

Question 4

What are stochastic effects from radiation?

Answer 4

probability to cause cancer, severity not dose dependent

Question 5

Younger people are more or less susceptible to developing cancers from radiation?

Answer 5

more

The younger the individual and the faster the tissue grows, the higher the potential risk to develop fatal cancer from being exposed to ionizing radiation

Question 6

What is the distance an operator should be from the radiation?

Answer 6

at least 6 feet from tube head or behind a barrier

Question 7

What principle should be used when taking radiographs?

Answer 7

ALARA

Question 8

A PA radiograph should include what structures?

Answer 8

tooth crown and at least 2 mm bone below apex

Question 9

What are the most radiosensitive head and neck structures?

Answer 9

thyroid
salivary glands
marrow
brain

Question 10

What is the recall radiation frequency of a HIGH risk caries patient

Answer 10

primary/mixed: 6-12 mo

permanent: 6-18 mo

Question 11

What is the recall radiation frequency of a LOW risk caries patient

Answer 11

primary/mixed: 12-14 mo
mixed/adolescent: 18-26 mo
adult: 24-36 mo

Question 12

Dental radiograph exposure (excluding CBCT) contribute to what % of total lifetime health care x-ray dose?

Answer 12

2.5%

Question 13

For a recall pt with clinical caries/increased risk of caries, what is the recommended frequency of radiographs?

Answer 13

6 to 12 months

After eruption of third molars: 6-18 months

Question 14

For a recall pt with no clinical caries and low risk, what is the recommended frequency of radiographs?

Answer 14

Primary/Transitional dentition: 12 to 24 months
Adult dentition: 18 to 36 months
After eruption of third molars: 24-36 months

Question 15

What is the justification principle?

Answer 15

exposure only justified if there is no other way to obtain information and only after review of patient’s dental and medical history and clinical examination, if available aways try to obtain previously taken radiographs.

Question 16

What is the optimization principle?

Answer 16

always try to obtain best quality images

Question 17

What does rectangular collimation do?

Answer 17

Reduces scatter thus improving image quality.

Reduces absorbed radiation dose by approx 50% and can omit use of protective apron.

Question 18

A thyroid shield is more effective if exposure is direct or indirect?

Answer 18

direct (i.e. Ceph)

Question 19

For analog films, what speed receptors are recommended

Answer 19

E or F (fast, similar to digital)

Question 20

Are there special recommendations for dental radiographs for those undergoing head and neck radiation therapy?

Answer 20

No

Question 21

How should field of view be positioned

Answer 21

As close to the area of interest as possible

Question 22

How do x-rays move from their source?

Answer 22

Divergent waves and beams become less intense as they move farther away from the source

Question 23

Are there special recommendations pregnant employees and radiographs?

Answer 23

No, use standard precautions

Question 24

For pts who cannot tolerate pano or intramural radiographs what is another alternative type of radiograph

Answer 24

lateral oblique

Question 25

What type of films are rare earth screens used for

Answer 25

Pano and Ceph

Question 26

What are the three type of digital receptors?

Answer 26

charged coupled devices (CCD)
complementary metal oxide semiconductors (CMOS)
phosphor storage plates (PSP)

Question 27

Exposure time ranking of digital and analog receptors

Answer 27

E/F = PSP > CCD = CMOS

longer) > (shorter/faster

Question 28

Cons of PSP

Answer 28

scratches and bite marks

Question 29

Cons of CCD and CMOS

Answer 29

bulky and connecting cable

Question 30

What should be the kVp of wall mounted machines

Answer 30

60-70 kVp

Question 31

Hand held x-ray machines have (longer/shorter) exposure time

Answer 31

Longer exposure time due to 60 kVp and lower mA

Question 32

Indications for a CBCT

Answer 32

impacted or supernumerary tooth
pathology and/or craniofacial anomaly
orthognathics
TMD

Question 33

Increasing mA or exposure time does what to the radiation dose

Answer 33

increases dose equally

Question 34

Methods to take radiographs on a severe gagger

Answer 34

distraction
topical lidocaine
nitrous oxide

Question 35

when should baseline anterior PA/occlusal be taken in the primary dentition

Answer 35

proximal surfaces cannot be visualized
hx of trauma
clinical pathology or anomaly

Question 36

what should be documented regarding radiographs

Answer 36

consent to obtain
# of exposures
diagnosis/analysis