Physics · Subtopic

Ultrasound

Piezoelectric transducers, frequency trade-offs, Doppler, and the artifact family (reverberation, mirror image, shadowing, enhancement). US physics is oral-boards-favorite territory — recognize the artifact, explain the mechanism.

Categories Click to drill this category

Basics →Piezoelectric effect, frequency/resolution, 1540 m/s, harmonics. Interactions →Acoustic impedance, specular vs scatter, attenuation. Doppler →Angle dependence, aliasing/Nyquist, CW vs PW, power Doppler. Artifacts →Reverberation, mirror image, shadowing, posterior enhancement. Bioeffects →TI/MI, ALARA for obstetric scans, contrast MI considerations.

Study loops Pick one

MCQ Bank (15)

ABR-style questions with rationale and references for every answer.

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Flashcards (15)

Doppler equation, impedance, artifact mechanisms, TI/MI definitions.

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Cases (3)

Absent carotid flow, Doppler aliasing in popliteal stenosis, clean vs dirty shadow.

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Domain Mock

Physics-only mock including CT, MRI, US, X-ray, and dose.

Microsims Interactive teaching tools

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Doppler Angle

Change θ between beam and flow — watch cos(θ) scale the Doppler shift and the measured velocity.

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Frequency & Penetration

Pick a probe frequency and target depth — see wavelength, attenuation, and axial resolution trade off.

Curated reading Go deeper

Ultrasound physics — Radiopaedia
Doppler ultrasound — Radiopaedia
Aliasing (Doppler) — Radiopaedia
Ultrasound artifacts — Radiopaedia
Mechanical Index — Radiopaedia
Bushberg — Essential Physics of Medical Imaging, Chapter 14