⊕ PET Camera Explorer — Physics & Image Quality

Interactive PET/CT teaching for second-year radiology residents: coincidence detection, detector design, TOF, reconstruction, attenuation artifacts, and the variables that make a study diagnostic.

1 PET/CT system & components

Click a part of the hybrid scanner to learn its role. Toggle crystal and photodetector technology — the detection chain updates in place. Fire an annihilation event to watch true, scatter, or random coincidences.

Scintillation crystal
Photodetector
Click a component for details
LSO crystal ring SiPM array Shared bed / table Patient · β⁺ activity e⁺e⁻ → 511 keV Energy + timing Coincidence processor Electronics / TOF Reconstruction OSEM + TOF Image recon CT CT gantry · μ-map PET/CT image · SUV
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Fire an event to watch two 511 keV photons leave the annihilation site, hit the crystal ring, and form a line of response — or scatter, random-coincide, or miss. Colored rays match the legend above.
Select a component on the scanner diagram to see how it contributes to PET image formation.

2 Acquisition & diagnostic quality

Manipulate the variables that drive true counts, scatter, randoms, resolution, and attenuation correction. Watch the whole-body PET MIP, quality score, coincidence mix, and SUV respond. Educational model — relative trends, not a vendor reconstructor.

Patient & tracer

~60 min is typical. Short uptake → activity still in blood pool; longer → more organ/lesion accumulation.

Well tolerated to ~210 mg/dL; higher competes with FDG → faint organs, activity shunted into muscle, nondiagnostic near 300.

Acquisition

TOF helps most in larger patients. Always review non-AC when CTAC looks odd.

Reconstruction

FBP: streaks, noisier. OSEM: smoother. TOF/PSF: better SNR/sharpness (PSF can edge-enhance).

Whole-body PET MIP

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Rotating whole-body maximum-intensity projection, skull base to mid-thigh, with normal physiologic FDG biodistribution.

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Composite quality: —
Trues —
Scatter —
Randoms —

SUV lab (teaching)

Image activity (rel)—
Reported SUV—
Lesion contrast—
NECR regime—

SUV ≈ tissue activity / (injected activity ÷ body habitus). Affected by uptake time, glucose, residual dose, partial volume, and reconstruction — not a pure “biology number.” PERCIST/Deauville need standardized protocols.

Artifact reference gallery

Select a classic PET/CT pitfall. Real open-access case figures appear below (the live MIP stays a clean physiologic study — no simulated artifacts).

Select an artifact card to show a real clinical teaching figure in this panel.
Pearl: Attenuation correction uses the CT μ-map scaled to 511 keV. Metal, contrast, truncation, and breathing misregistration corrupt AC — always check the non-AC PET when something looks wrong. 511 keV photons are highly penetrating; PET room shielding differs from Tc-99m labs.

3 Detector & system numbers

Board-relevant contrasts among common scintillators and system choices. The column for your selected crystal is highlighted. Values are typical textbook ranges.

Feature BGO LSO LYSO Why it matters

4 Check yourself — ABR-style quiz

Board-style questions on coincidence physics, instrumentation, TOF, reconstruction, CTAC artifacts, and SUV. One at a time; shuffle each session.

Session complete
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Nice work. Reshuffle to try a new order.

Score: 0 / 0