Carlton Ch. 14

What is Exposure?

Radiation intensity in air, measured in roentgens (R).

What is Dose?

Amount of radiation absorbed, measured in rad.

What is the diagnostic use of ionizing radiation?

A decision involving the balance between potential risks and diagnostic benefits when using ionizing radiation.

What is Maximum exposure calculation?

The maximum radiation exposure calculated at the minimum Source-to-Object Distance (SOD).

Why should you overestimate exposure?

When estimating radiation exposure, it is preferable to do this rather than underestimate to ensure safety.

What is the Calculation of mR/mAs?

This is required for estimating Entrance Skin Exposure (ESE) and varies between X-ray machines/tubes.

What is ESE for fluoroscopic equipment?

Entrance Skin Exposure for fluoroscopic equipment, measured in R/min.

What is 11.5 R/min (10 cGy/min)?

Standard Fluoroscopy ESE

What is 23 R/min (20 cGy/min)?

High-Level Control Fluoroscopy ESE

Why is Communication important in radiology?

Essential to gain patient confidence and ensure cooperation during radiological procedures.

What are Different Projections in radiology?

Different radiological views that result in variations in Entrance Skin Exposure (ESE) and absorbed dose values.

What is PA female pelvis vs AP?

This projection results in lower ovarian exposure compared to AP.

What is PA skull vs AP?

This projection results in lower exposure to the lens of the eye compared to AP.

What is Immobilization?

Technique that reduces retakes due to motion artifacts and improves image quality.

What is Prime factors interrelationship?

Kilovoltage, milliamperage, time, distance, focal spot size, and filtration.

What are Other factors affecting patient dose?

Field size, gonad shielding, subject part density, grids.

What happens if you Increase in kVp without mAs compensation?

Increases dose if not compensated with mAs adjustment.

What happens if you Increase in kVp with mAs compensation?

Decreases dose if accompanied by mAs adjustment.

What is Optimum kVp?

Matching this with the k-edge of the detector material is ideal for optimum image quality and dose efficiency.

What happens if you Increase in mAs?

Increases patient dose if not properly compensated.

Why should you use the Lowest possible mAs?

Decreases patient dose.

What happens if you Increase in SID or SOD?

Results in Entrance Skin Exposure (ESE) decrease.

What happens if you Decrease in OID?

Increasing this increases SOD, therefore, ESE decreases.

What happens with you use Increased filtration?

Decreases Entrance Skin Exposure (ESE) when combined with kVp modification.

What happens with you use Increased filtration with mAs modification?

Increases Entrance Skin Exposure (ESE) when mA is modified to maintain image quality.

Why should you Decrease primary beam size?

Decreases patient dose.

When might a Marginal mAs increase be needed?

May be needed when there is a significant reduction in field size.

What is Reduction in patient exposure from collimation?

More significant in reducing patient exposure than marginal increases in mAs.

How does Higher ratio grid affect patient dose?

Requires increased mAs, which increases patient dose.

Why should you Use the lowest ratio grid necessary?

Ensures adequate image quality without unnecessary dose increase.

What are Digital Image Receptor Systems?

Have a wide dynamic range and respond to exposures from 0.01 mR to 100 mR.

Why are Extreme exposures unacceptable in digital imaging?

Can produce digital data drop and excessive scatter.

Why should you Avoid overexposing in digital imaging?

Should be avoided despite the ability to adjust images after they are taken.