Diagnostic Radiology Physics: Topic Map

1. Fundamentals of atomic structure and electromagnetic radiation
   • Atoms, ions, electron shells, binding energy
   • Electromagnetic spectrum
   • Frequency, wavelength, energy, inverse-square law
2. Production of X-rays
   • X-ray tube construction
   • Cathode, anode, focal spot, rotating anode
   • Thermionic emission
   • Bremsstrahlung and characteristic X-rays
   • Tube voltage (kVp), tube current (mA), exposure time, mAs
   • Heel effect and heat management
3. Interaction of X-rays with matter
   • Coherent (Rayleigh) scatter
   • Photoelectric effect
   • Compton scatter
   • Pair production and photodisintegration
   • Attenuation, half-value layer, linear attenuation coefficient
   • Factors affecting contrast and scatter
4. Image formation and image quality
   • Radiographic density or receptor exposure
   • Contrast, spatial resolution, sharpness, noise
   • Magnification, distortion, focal spot blur
   • Grids, collimation, filtration, air-gap technique
   • Exposure factors and their effects
5. Conventional radiography and fluoroscopy
   • Film-screen radiography basics
   • Digital radiography: CR and DR
   • Fluoroscopic imaging chain
   • Image intensifier and flat-panel detector
   • Automatic exposure control
   • Pulsed fluoroscopy and dose reduction
6. Computed tomography (CT)
   • CT number and Hounsfield unit
   • Scanner generations and helical CT
   • Detectors, gantry, pitch, collimation
   • Image reconstruction: filtered back projection and iterative reconstruction
   • Window width and level
   • CT artifacts and radiation dose
7. Magnetic resonance imaging (MRI)
   • Nuclear magnetic resonance
   • Hydrogen proton behavior and Larmor frequency
   • T1, T2, and T2* relaxation
   • Pulse sequences: spin echo, gradient echo, inversion recovery
   • T1-, T2-, PD-, FLAIR-, STIR-, DWI-weighted imaging
   • K-space, gradients, coils, MRI artifacts
   • MRI safety and contrast agents
8. Ultrasound and Doppler
   • Sound-wave properties
   • Piezoelectric effect and transducers
   • Reflection, refraction, scattering, attenuation
   • Acoustic impedance
   • B-mode, M-mode, color Doppler, power Doppler, spectral Doppler
   • Doppler equation, aliasing, artifacts
   • Ultrasound safety: thermal index and mechanical index
9. Nuclear medicine
   • Radioactivity and types of decay
   • Half-life, activity, units: Bq and Ci
   • Gamma camera and collimators
   • SPECT, PET, coincidence detection
   • Common radionuclides and radiopharmaceutical principles
   • Radiation safety in nuclear medicine
10. Radiation quantities, biologic effects, and protection

• Absorbed dose: gray (Gy)
• Equivalent and effective dose: sievert (Sv)
• Exposure and air kerma
• Deterministic versus stochastic effects
• ALARA principle
• Time, distance, shielding
• Personnel monitoring, pregnancy, and patient dose optimization

1. Contrast media physics and safety

• Iodinated contrast in CT and radiography
• Gadolinium-based contrast in MRI
• Ultrasound microbubble contrast
• Contrast reactions, renal considerations, extravasation

1. Quality assurance and common artifacts

• Acceptance testing and routine QC
• Radiography, CT, MRI, ultrasound, and nuclear medicine artifacts
• Methods to recognize, prevent, and correct artifacts

High-level overview