Ch.3 Math

Question 1

measures the rate at which xrays are produced
-mA x Seconds

Answer 1

mAs

Question 2

the distance between the radiation source & the IR

Answer 2

Source-to Image-Distance (SID)

Question 3

Intensity DECREASES when the distance INCREASES

Answer 3

Inverse square law

Question 4

mAs INCREASES when the distance INCREASES

Answer 4

Direct square law

Question 5

I1/I2 = (S2/S1)2

Answer 5

Inverse Square Law Formula

Question 6

mAs1/mAs2 = (SID1/SID2)2

Answer 6

Direct Square Law Formula

Question 7

kvp is INCREASED to LENGTHEN the scale of contrast; AKA “decrease Contrast” (gray image)

Answer 7

15 % rule: decreasing contrast (Adding Gray)

Question 8

kVp is DECREASED to SHORTEN the scale of contrast; AKA “increase contrast” (B&W image)

Answer 8

15% rule- Increasing Contrast (B&W)

Question 9

Decrease kVp by 15% (.85) & multiply mAs by 2

Answer 9

15% rule- Decrease contrast Formula

Question 10

Increase kVp by 15% (1.15) & divide mAs by 2

Answer 10

15% rule- Increase contrast Formula

Question 11

volume = Dose/Strength

Answer 11

Medication Dose Calculation Formula