Radiation Protection

Question 1

Maximum Permissible Dose

Occupational limits
Non-occupational limits
Pregnant women:

Answer 1

50 mSv
5 mSv
1 mSv

Question 2

Most dose you can give your patient in FMX, what type of film:

Answer 2

D-speed film

PSP or F-speed film has half the dose as D-speed film.
CCD sensor is half of PSP

Question 3

Which type of cancers have the highest risk from dental radiographic exposure?

Answer 3

Leukemia and thyroid cancer

Question 4

guiding principles of radiation protection

Answer 4

1.) decide if u really need to take the radiograph
2.) if you do, keep dose as low as possible
3.) Does our patient have a maximum permissible dose? no. because we’re treating them.

Question 5

ALARA:

Answer 5

As low as reasonably achievable.

definition: dose as low as possible and still get enough diagnostic information.

Question 6

Do you take an FMX on every new patient?

Answer 6

No.

Question 7

US food and drug administration guidelines for dental radiographs:

Answer 7

thorough clinical examination, consideration of patient history, review of prior radiographs, caries risk assessment, consideration of both dental / general health needs should all PRECEDE radiographic examination.

Question 8

Filtration:

Inherent filtration:

Answer 8

when primary beam passes through the glass window of x-ray tube, insulating oil, tube head seal. Goes through ADDEDD ALUMINUM DISKS (aluminum filtration)

Question 9

What does the aluminum filter do?

Answer 9

Blocks low energy photons
(gets rid of low energy filtration)

Question 10

Mandated minimum total filtration for x-ray tubes

important:

Answer 10

Operating kV - > Aluminum filtration (mm)
<50 -> 0.5 mm
50-70 -> 1.5 mm
>70 -> 2.5 mm

Question 11

Beam collimation

Maximum size of our beam can only be how long?

important:

Answer 11

2.75 inches in diameter.

Question 12

3 basic types of PIDs (cones)

which one is illegal in several states now?

Answer 12

conical **
rectangular
round

Question 13

Dose reduction mechanisms:

important, know all mechanisms

Answer 13

rectangular collimator
HIGHER kV GENERATOR**
constant potential machine: get more consistent high energy x-ray beam to patient. no alternating current of high low high low energy
increased focal length: (longer cone length)

Question 14

penumbra:

Answer 14

area of blurriness

note: umbra: area of sharpness

Question 15

ideal tube-head set up:

Answer 15

constant potential voltage
high kV x-ray
long target to receptor distance
rectangular collimator
proper aluminum filtration

Question 16

Operator should never hold the film for the patient

T/F

Answer 16

True

patient, legal guardian can hold but no employees

Question 17

position and distance from x-ray if no shielding :

Answer 17

6 ft away
90-135 degrees to primary beam