X-Ray Production & Generators
As electrons accelerate from the cathode to the anode, their high potential energy is fully converted into this type of energy.
What is kinetic energy?
This law dictates that doubling your Source-to-Image Distance (SID) will reduce the X-ray intensity reaching the receptor to exactly one-fourth of its original value
What is the Inverse Square Law?
This low-energy interaction occurs when an X-ray photon is deflected by an atom without losing any energy or causing ionization.
What is coherent (or classical/Thomson) scattering?
Negative contrast agents like air or carbon dioxide create structural contrast on a radiograph due to this physical property
What is being less dense (lower physical density and lower atomic number) than surrounding tissues?
This process is defined as the spontaneous emission of energy or particles from an unstable atomic nucleus.
What is radioactivity?
This formula determines the total heat units (HU) generated during a standard single-phase fluoroscopic exposure.
What is $\text{kVp} \times \text{mA} \times \text{time (seconds)}$?
This mathematical relationship describes how the total intensity (quantity) of the X-ray beam changes when a radiographer strictly alters the kVp setting.
What is proportional to the square of the kVp? IntensityXkVp^2
This interaction involves an incoming photon colliding with an outer-shell electron, ejecting it as a recoil electron and creating the primary source of diagnostic scatter.
What is Compton scattering?
At standard diagnostic energies, bone produces significantly higher radiographic contrast than soft tissue primarily due to this interaction type.
What is photoelectric absorption?
While technically identical in wave behavior, X-rays and gamma rays differ entirely based on this property.
(Gamma rays come from the nucleus; X-rays come from electron shell interactions).
This specific type of generator produces more efficient X-rays per mAs than a single-phase generator, resulting in lower patient dose for equivalent receptor exposure.
What is a high-frequency generator?
This specific metric describes the exact thickness of aluminum required to cut the primary X-ray beam's exposure rate perfectly in half.
What is the Half-Value Layer (HVL)?
This interaction cannot occur within standard diagnostic radiography because it requires a threshold photon energy of at least 1.02 MeV.
What is pair production?
Barium ($Z=56$) appears dramatically more opaque (white) on an image than an identical concentration of Iodine ($Z=53$) at the same kVp because of this atomic property.
What is a higher atomic number Z?
An atom's chemical identity and atomic number Z are entirely determined by the count of these positive subatomic particles.
What are protons?
This transformer rule determines the exact number of secondary turns required when given the primary turns, primary voltage, and a target high voltage (kVp).
What is the Transformer Law? Vs/Vp =Ns/Np
These "useless," low-energy photons (typically below 15 keV) are intentionally removed from the diagnostic beam to lower patient skin dose.
What is soft radiation (or low-energy/long-wavelength X-rays)?
This extreme interaction requires high-energy gamma rays above 10 MeV to directly enter the nucleus and eject a nuclear fragment.
What is photodisintegration?
This clinical mechanism is the primary reason why a Compton recoil electron poses a risk to patients during an exam.
What is depositing kinetic energy into local tissue (contributing to patient radiation dose)?
This algebraic formula is used to calculate the absolute maximum capacity of electrons any given shell can hold.
What is 2n^2
This phenomenon limits the maximum X-ray tube output at very low kVp settings, causing a plateau despite an abundance of available thermionic electrons.
What is the space charge effect?
If a radiographer simultaneously doubles the mAs and heavily increases the beam filtration, this is the net effect on the beam's overall intensity and average energy.
What is an increase in beam quality (average energy) while the net intensity (quantity) may remain relatively stable or change depending on the exact filtration thickness?
As kVp is increased from a low setting to a high setting (e.g., 60 to 100 kVp), this happens to the relative proportion of photoelectric interactions compared to Compton interactions.
What is a decrease? (The proportion of Compton scattering increases relative to photoelectric absorption).
This mechanical or digital technique is the most effective way to eliminate scattered photons from reaching the image receptor without modifying the primary beam's initial intensity
What is using a radiographic grid (or collimation)?
This specific structural term describes atoms that share the exact same number of protons but differ in their neutron count.
What are isotopes?