Exposure Ch. 12

Given 10mAs and an mA of 400, what is the exposure time?

a. 0.0025 second b. 25 millisecond c. 1/4 second d. 1/4 millisecond B.

What is the resultant mAs from 80 mA and 50 ms?

a. 1.6 mAs b. 40 mAs c. 16 mAs d. 4 mAs D.

What is 25 ms in fraction form?

a. 1/40 millisecond b. 1/4 second c. 1/40 second d. 1/4 millisecond C.

Due to patient situation, the SID for a pelvis exam is increased from 40 inches to 50 inches. What mAs would be needed to maintain the exposure if the original mAs was 30?

a. 15 mAs b. 47 mAs c. 19 mAs d. 55 mAs B.

Which set of technical factors would result in the highest exposure?

a. 200mA, 0.15 seconds, 45" SID b. 100mA, 0.3 seconds, 40" SID c. 300mA, 50 milliseconds, 40" SID d. 600mA, 0.025 seconds, 45" SID B.

An x-ray exposure of 35 mR is recorded at 40 inches. To reduce the exposure to 25mR, what would the new distance be?

a. 30" b. 50" c. 34" d. 47 D. (Inverse Square Law)

If the exposure time for an image was 15 ms, and the mAs was 6, what was the mA used?

a. 300 mA b. 40 mA c. 400 mA d. 30 mA C.

To reduce motion artifact in pediatric imaging, while maintaining the current exposure, how could the following set of technical factors be adjusted? 100mA, 0.1 seconds, 65kVp

a. 50mA, 0.1 seconds, 75kVp b. 200mA, 0.05 seconds, 65kVp c. 50mA, 0.2 seconds, 65kVp d. 200mA, 0.1 seconds, 55 kVp B.

300 mA * 200 ms = ___ mAs

a. 600 mAs b. 6 mAs c. 60,000 mAs d. 60 mAs D.

If 18 mR of exposure was received at 72 inches, how many mR of exposure would be received at 36 inches? Hint: Inverse square law

a. 80 mR b. 36 mR c. 9 mR d. 72 mR D.

The default technique for an image is 75 kVp and 40 mAs. If you wanted to alter the contrast by raising the kVp but wanted to maintain the exposure, what technique would you use?

a. 86 kVp, 20 mAs b. 150 kVp, 34 mAs c. 86 kVp, 34 mAs d. 150 kVp, 20 mAs A.

What is the inverse square law? I(1)/I(2) = D2^2/D1^2

a. Allows you to change exposure without changing exposure factors b. A calculation used to quality check x-ray tubes c. Provides technique correction for change in SID d. Intensity of radiation at a given distance from point source is inversely related to the square of the distance between the object and source D.

With all other technical factors remaining the same, decreasing the kVp by 15% would:

a. Decrease exposure by 15% b. Halve the exposure c. Quadruple the exposure d. Double the exposure B.

If the mAs is doubled from 10 to 20, the resulting radiograph will exhibit:

a. Decreased exposure by half b. Increased exposure by double c. Increased HVL by double d. Increased contrast by double B.

To quadruple the exposure, you would:

a. Double the kVp b. Increase kVp by 15% c. Halve the distance d. Double the mAs C.

What type of relationship does current have with beam intensity?

a. Inverse b. Indirect c. Direct d. Abstract C.

Which of the following is a prime factor?

a. Milliamperage-Second (mAs) b. Kilovoltage (kVp) c. Distance (d) d. All of the above D.

Soft x-rays:

a. Penetrate less b. add density c. Penetrate more d. add contrast A.

What is Milliamperage (mA)?

a. The length of exposure, measured in seconds or milliseconds (ms) b. A measurement of x-ray tube current - the number of electrons crossing the tube from cathode to anode per second. c. A measure of the amount of energy in the x-ray beam. d. The distance between the x-ray source and the image receptor B.

What does kilovoltage (kVp) have a direct influence on?

a. The number of electrons created in the x-ray tube b. Exposure time c. The speed and energy of electrons applied across the x-ray tube. d. Grid artifacts C.

What is exposure time?

a. The only factor influencing the change in exposure intensity b. The length of exposure, measured in seconds (s) or milliseconds (ms) c. Expressed in amperes or amps (A) d. A measurement of x-ray tube current - the number of electrons crossing the tube from cathode to anode per second. B.

What is mAs reciprocity?

a. The reciprocal of the mA will give the same exposure b. The same image receptor exposure will result from different mA and time selections as long as their product remains the same. c. Each mA and time combination results in a different and unique image receptor exposure d. The same image receptor exposure will result from different mA and time selections as long as their sum remains the same. B.

What is x-ray quality?

a. X-ray quality is a measure of the number of x-ray photons in the useful beam. b. X-ray quality is a measurement of the clarity of the image. c. X-ray quality is a measure of the total combined technical factors used to produce the x-ray beam. d. X-ray quality is a measurement of the penetrating ability of the x-ray beam. D.

What is x-ray quantity?

a. X-ray quantity is a measurement of the penetrating ability of the x-ray beam. b. X-ray quantity is a measure of the number of x-ray photons in the useful beam. c. X-ray quantity is another team for total milliamperage-seconds. d. X-ray quantity is a measure of the total number of x-ray interactions. B.

What factors influence x-ray quantity?

a. kVp, distance, filtration, patient size b. mAs, kVp, OID, filtration c. kVp, distance, filtration, shielding d. mAs, kVp, distance, filtration D.