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RAD 202: Radiographic Physics > Ch 1 > Flashcards

Flashcards in Ch 1 Deck (18)
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1

Milliamperage seconds (number of electrons and number of x-rays)
mA x time

mAs

2

Source to image receptor (as far back as possible)

SID

3

Object to IR distance
Always want object as close to IR as possible otherwise magnification distortion occurs (ex: shadow)
Want heart closer to IR

OID

4

Kilovoltage peak (penetrating ability of x-rays)

kVp

5

One thousandth of the unit to which it's joined

Milli

6

1/1000 ampere (1000 mA = 1 A)

Milliampere

7

1/1000 second (1000 ms = 1 s)

Millisecond

8

1/1000 meter (1000 mm = 1 m)

Millimeter

9

An amount 1000 times the unit to which it's joined

Kilo

10

1000 volts

Kilovolt

11

1000 grams

Kilogram

12

Intensity of the beam is "inversely" proportional to the "square of the distance"
Intensity of the beam decreases by 4 when the distance is doubled and is increased by 4 when the distance is halved
I1/I2=D2^2/D1^2

Inverse square law

13

Formula used when changing distances (SID)
Directly proportional
mAs1/mAs2=D1^2/D2^2

Exposure/density maintenance formula

14

Similar triangles formula

b/B=h/H

15

What does b in similar triangles formula represent?

Base of small triangle (object)

16

What does B in similar triangles formula represent?

Base of big triangle (IR)

17

What does h in similar triangles formula represent?

Height of small triangle (distance from object to source)

18

What does H in similar triangles formula represent?

Height of big triangle (SID)