radiation protection aka dose reduction mechanisms

Question 1

two goals for oral and maxillofacial radiology

Answer 1

1. reduce radiation exposure
2. maintain high degree of diagnostic efficiency

Question 2

-Since the probability or severity of biological
damage increases as the radiation dose
increases, it is desirable to avoid receiving even
the smallest dose of radiation unnecessarily.

-time, distance, and shielding factors were prioritized

Answer 2

ALARA
as low as reasonably achievable

(guiding principle of radiation protection)

Question 3

does reduction mechanisms
xray tube head (mandated)

Answer 3

1. filtration
2. collimation

Question 4

filtration blocks

Answer 4

long wave lengths and only allows short wavelengths to reduce radiation

Question 5

• Selective passage of contents through a
  specified substance
• Selectively removes a greater proportion of
  low keV x-ray photons
• Increases mean energy of the beam

Answer 5

filtration

Question 6

mandated minimum total filtration for xray tubes
operating kv…
<50 =
50 to 70 =
>70 =

what are aluminum filtration (mm)

Answer 6

aluminum filtration(mm)
<50 = 0.5mm
50 to 70 = 1.5mm
>70 = 2.5mm

Question 7

exit side beam, collimation max is what diameter

Answer 7

2.75 inches “
(rectangular preferred)

Question 8

1. rectangular collimator
2. High kV generator/
   transformer
3. Constant potential
   (DC) fully rectified
4. Increased focal length

this shape of collimator:

Answer 8

xray tube head options for dose reduction me

Question 9

area exposed is related to the

Answer 9

maximum size of the beam

Question 10

effect dose for common exams,

FMX PSPP-rectangle coll=
FMX CCD- rectangle coll=
FMX PSPP- round coll=
FMX CCD- round coll=

so basically, ____coll has less radiation exposed

Answer 10

FMX PSPP-rectangle coll=35
FMX CCD- rectangle coll=17
FMX PSPP- round coll=171
FMX CCD- round coll=85

RECTANGLE better

Question 11

lower dose with ___kV

Answer 11

higher

units are larger
heavier
more money

Question 12

increased of long BID benefits: (increased focal distance)

Answer 12

1. 27% less head volume
2. reduced effective dose
3. sharper image

Question 13

Dose Reduction Mechanisms Practice Options

Answer 13

1. Sensor speed (sensitivity)
2. Lead (Pb) thyroid collar
3. Film-holding devices with beam alignment capability
4. Time-temperature or digital quality control processing

Question 14

film speed:

Answer 14

-D speed (ultraspeed)
-E speed
-F speed (insight)
-digital receptors:
1. PSPP
2. CCD (more sens tho)
3. CMOS (seen most)

Question 15

patient protection

Answer 15

lead apron and thyroid collar

Question 16

2 recommendations for patient shielding during dentomaxillofacial radiology

Answer 16

1. stop shielding of gonads, pelvic and fetus
2. stop thyroid cover

Question 17

during an exposure taken with wall-mounted xray unit, the operator shall stand

Answer 17

behind protective barrier

Question 18

if barrier not present for operator they should

Answer 18

stand 6 feet from patient at angle between 90-135 degrees to the direction of the useful beam

Question 19

never stand

Answer 19

in the primary beam

try to stand behind barrier

Question 20

worn by all full-time
operators of radiographic equipment while xray exposures are being made.

Answer 20

Dosimeter badges

Question 21

annual occupational whole body exposure will not exceed

Answer 21

50mSv

Question 22

operators who have declared preg will not receive more than __mSv to the embryo or fetus during the term of pregnancy

Answer 22

5