Summary of Techniques Used for Parathyroid Scintigraphy and PET/CT
| Technique | Radiopharmaceutical* | Effective dose (mSv)† | Protocol of administration | Suggested acquisition protocol | Total acquisition time |
|---|---|---|---|---|---|
| 99mTc-sestamibi/123I (subtraction) | 123I (∼12 MBq) | 1.5 | T0: 123I (intravenous or oral) | 99mTc and 123I simultaneous dual-isotope acquisition starting 3–5 min after 99mTc-sestamibi injection‡ | <1 h |
| 99mTc-sestamibi (∼600 MBq) | 5.4 | T+2 h: 99mTc-sestamibi (intravenous) | Image of thyroid/parathyroid bed with pinhole collimator (15 min) | ||
| Planar image of neck and mediastinum (5 min)§ | |||||
| Then, dual-isotope SPECT/CT acquisition (∼25 min) | |||||
| 99mTc-sestamibi (dual-phase) | 99mTc-sestamibi (740–900 MBq) | 6.7–8.1 | T0: 99mTc-sestamibi (intravenous) | T+15 min (early phase); planar image of neck and mediastinum (5 min)§ | ∼90 min in 2 sessions |
| Image of thyroid/parathyroid bed with pinhole collimator (15 min) | |||||
| T+2 h (delayed phase); same protocol as early phase | |||||
| SPECT/CT (∼25 min) at early, delayed, or both phases | |||||
| 18F-fluorocholine PET/CT (± CECT) | 18F-fluorocholine (100–200 MBq or 2–3 MBq/kg) | 2.0–4.0 | T0: 18F-fluorocholine (intravenous) | PET acquisition starting ∼45 min (30–60 min) after injection¶ | 20–30 min |
| Nonenhanced CT from mandible to carina | |||||
| If arterial-phase CECT is added, then acquisition starts ∼30 s (25–40 s) after beginning of contrast medium injection |
* Values in parentheses are activities.
↵† Not including CT dose (25). For 123I, we considered thyroid uptake of 20%.
↵‡ Example of nonoverlapping windows (29): for 99mTc, 140 keV ± 7% (130–150 keV); for 123I, 159 keV −4% to +10% (153–175 keV).
↵§ Includes submandibular salivary glands and upper part of myocardium.
↵¶ Early phase (∼ 5 min after injection) is additionally obtained by some authors.
CECT = contrast-enhanced CT; T = time.