Chapter 9: X-ray Emission

What does mAs determine in X-ray production?

The quantity of x-rays produced. Doubling mAs, doubles the intensity

What does kVp control in X-ray production?

The energy and penetrability of the X-ray beam. Doubling kVp increases intensity by a factor of 4.

What happens to intensity as distance increases?

Intensity decreases(Inverse square Law)

What does filtration do to X-ray intensity?

Reduces it by removing low-energy x-rays. which improves patient safety.

What is penetrability?

The ability of X-rays to pass through matter. Higher kVp = higher penetrability

What is the Half-Value Layer?

The thickness of material needed to reduce X-ray beam intensity by half. It measures beam quality.

What factors affect X-ray energy?

kVp, filtration, and target material(Aluminum)

What is inherent filtration?

Filtration built into the X-ray tube, such as the glass envelope and cooling oil.(0.5-1.0mm Aluminum equivalent)

What is added filtration?

Additional layers of material outside the tube to improve beam quality and reduce patient dose.

What is compensating filtration?

Filtration is used to balance exposure in areas with varying thickness, like a wedge filter for a foot.

What is the 15% rule?

Increasing kVp by 15% doubles beam intensity, so to maintain exposure divide mAs by 2.

Decreasing kVp by 15% havles intensity, so to maintain espusre multiply mAs by 2.

Why is filtration so important?

It reduces patient dose, improves image quality by increasing beam uniformly, and ensure safety compliance.

Attenuation

Is the reduction in X-ray intensity that results from absorption and scattering

X-ray intensity is

the number of x-rays in the useful beam

xray intensity is proportional to

kvp²

If you were to double kvp

the x-ray intensity would increase by a factor of 4

Square Law

Is compensating for a change in SID by changing mAs by the factor SID²

Square Law can be also called

Exposure maintenance Formula

Factors influencing x-ray beam energy are

kvp and added filtration

What affects x-ray intensity?

mA, mAs, and distance

The energy of x-rays is measured in

HVL