Mastering X-ray Equipment and AEC

Radiation Types

• Characteristic radiation is also known as 'slow-down radiation' and occurs within the diagnostic range.

X-ray Energy

• Between 0-70 kVp, the x-ray energy is low, resulting in a higher absorption rate.

X-ray Absorption

• Low-energy x-rays have more opportunity to be absorbed due to their shorter wavelength.

Image Quality

• Resolution is the principle component of image quality that refers to the ability of the imaging system to image small and closely spaced objects.

Attenuation Differences

• Attenuation differences in a radiograph are caused by the varying densities of the object being imaged.

Contrast and Remnant Beam

• The term used to describe the relative magnitude of differences within the remnant beam exiting the object is contrast.
• Contrast is the factor that affects the magnitude of contrast on a radiograph.

X-ray Emission Spectrum

• The size and relative position of the x-ray emission spectrum are affected by the x-ray tube voltage.

Radiation Quantity

• The primary controller of radiation quantity is the milliamperage (mA).

Inverse Square Law

• The formula for the Inverse Square Law is I₁ / I₂ = (d₂ / d₁)², where I is the intensity and d is the distance.
• Using the Inverse Square Law, if the distance is increased from 20 inches to 40 inches, the exposure will decrease to 60 mR.

Subject Contrast

• The following factors affect subject contrast in a radiograph: atomic number, density, and thickness of the object.

Digital Detectors

• The main difference between CR and DR digital detectors is the type of detector used: image plate versus flat-panel detector.

Contrast Potential

• The most relevant description of contrast potential in a digital image is the ability to visualize subtle differences in density.

Quantum Noise

• The main cause of quantum noise in digital x-ray is the random variation in the number of x-rays interacting with the detector.

X-ray Room Equipment

• Room 3 in B114 uses a ceiling tube mount.
• Three of the x-ray suites in B114 have the option of using Automatic Exposure Control.
• Room 2 possesses a challenge for trauma cases such as shoot through hip.

Clinic Practice

• The unit of measurement for x-ray exposure can be found in clinic practice.

Skin Dose

• As the x-ray tube gets closer to the patient, the skin dose increases.

Image Sharpness

• The following factors generally control the sharpness of image detail in an imaging system: focal spot size, geometric magnification, and motion.

Magnification Factor

• The magnification factor can be calculated using the formula: M = SID / SOD, where M is the magnification factor, SID is the source-to-image receptor distance, and SOD is the source-to-object distance.

Edge Gradient Blurring

• The formula for calculating the edge gradient blurring (f) in terms of magnification (M) and focal spot (F) is: f = M × F.

Shape Distortion

• The critical distance for shape distortion in radiography is 40 cm.

Focal Spot

• The focal spot in an x-ray tube is angled to reduce the heel effect.

Contrast and Anode Heel Effect

• The anode heel effect causes a decrease in intensity and contrast on the anode side of the x-ray beam.

Parallel and Divergent X-ray Beams

• Parallel x-ray beams have a uniform intensity and do not diverge, while divergent x-ray beams have a decreasing intensity and diverge as they travel away from the source.