Radionuclide Therapy: Administration Protocols
Representative activities, schedules, premedication, monitoring, and release by therapy
Quick Answer
This is a representative administration reference for radionuclide therapies — typical activity/schedule, key premedication, monitoring, and radiation-safety/release considerations. Every therapy requires a written directive (US NRC), appropriate patient selection (often imaging-based), and release criteria (TEDE to others ≤ 5 mSv). Activities and schedules are guideline- and indication-specific; several are moving from fixed toward dosimetry-guided dosing.
⚠️ Representative parameters — verify against current SNMMI/EANM guidance, prescribing information, and local/regulatory protocol. A written directive is required before administration of any therapy dose.
Iodine-131 — Benign & Differentiated Thyroid Cancer
| Indication | Typical activity | Preparation / notes |
|---|---|---|
| Graves hyperthyroidism | ~10–15 mCi fixed (or calculated) | Aim for hypothyroidism; low-iodine; exclude pregnancy; outpatient |
| Toxic nodular disease | calculated (often higher) | Autonomous tissue concentrates; suppressed normal gland spared |
| DTC remnant ablation | ~30 mCi (low risk) | HiLo/ESTIMABL non-inferiority; TSH > 30; low-iodine |
| DTC adjuvant | ~30–150 mCi (by risk) | Presumed microscopic residual |
| DTC therapy (structural) | ~100–200 mCi empiric, or dosimetry | Post-therapy WBS 3–7 days (upstages) |
I-131 practicalities: low-iodine diet, hold iodinated contrast/amiodarone, TSH > 30 (withdrawal or rhTSH), hydration, sialagogues (reduce sialadenitis), bowel regimen; inpatient isolation if retained activity/dose rate exceeds release limits; exclude pregnancy/lactation.
PRRT & PSMA Radioligand Therapy
| Therapy | Activity / schedule | Premedication / monitoring |
|---|---|---|
| ¹⁷⁷Lu-DOTATATE | 7.4 GBq (200 mCi) q8 weeks × 4 | Amino-acid renoprotection (arginine/lysine) + antiemetics; CBC, renal, chromogranin A between cycles |
| ¹⁷⁷Lu-PSMA-617 | 7.4 GBq q6 weeks × up to 6 | PSMA-positive selection (± FDG); salivary/renal dose-limiting; CBC/renal |
Both are largely outpatient (Lu-177 is a low-energy β with a modest imageable γ); post-therapy SPECT/CT confirms distribution and supports dosimetry.
Bone-Targeted Therapy
| Therapy | Activity / schedule | Notes |
|---|---|---|
| ²²³Ra-dichloride | 55 kBq/kg IV q4 weeks × 6 | Symptomatic bone-only mCRPC; check counts before each; avoid abiraterone+prednisone (ERA-223); follow ALP (PSA unreliable) |
| Sm-153-EDTMP (bone pain) | ~1.0 mCi/kg | β-emitter for osteoblastic bone-pain palliation; myelosuppression |
| Sr-89-chloride (bone pain) | ~4 mCi (148 MBq) fixed | Longer-acting; delayed, sometimes prolonged myelosuppression |
Liver-Directed (Y-90)
| Therapy | Activity | Workflow |
|---|---|---|
| ⁹⁰Y radioembolization | Individualized by dosimetry | Mandatory ⁹⁹ᵐTc-MAA mapping first (lung-shunt, extrahepatic); post-therapy Y-90 PET/bremsstrahlung SPECT |
MIBG & Radioimmunotherapy
| Therapy | Activity | Notes |
|---|---|---|
| I-131-MIBG (iobenguane) | high-activity, MIBG-avid disease (pheo/para, neuroblastoma) | Thyroid blockade; confirm avidity on diagnostic I-123-MIBG; inpatient per dose rate |
| ⁹⁰Y-ibritumomab tiuxetan | weight- and platelet-based (capped) | Rituximab pre-dose; delayed myelosuppression; require adequate marrow reserve and < ~25% marrow involvement |
Cross-Cutting Requirements
| Requirement | Detail |
|---|---|
| Written directive (NRC) | Required for any therapy dose; I-131 > 30 µCi |
| Patient selection | Often imaging-based (Krenning ≥ 3 for PRRT; PSMA-positive for RLT; MIBG avidity for I-131-MIBG) |
| Pregnancy/lactation | Exclude pregnancy; lactation ceased (I-131) |
| Release criteria (10 CFR 35.75) | TEDE to others ≤ 5 mSv; surrogates ≤ 33 mCi I-131 or ≤ 7 mR/hr at 1 m; written instructions if projected > 1 mSv |
| Monitoring | CBC/renal per agent; disease-specific markers (Tg, chromogranin A, ALP, PSA context) |
Board-Level Synthesis
Anchor activities: I-131 ablation ~30 mCi (low-risk), therapy ~100–200 mCi (or dosimetry); ¹⁷⁷Lu-DOTATATE 7.4 GBq q8wk ×4 (amino-acid renoprotection); ¹⁷⁷Lu-PSMA 7.4 GBq q6wk ×up to 6; ²²³Ra 55 kBq/kg q4wk ×6; Y-90 individualized by dosimetry after MAA mapping.
Every therapy needs a written directive and imaging-based selection (Krenning ≥ 3, PSMA-positive, MIBG-avid), plus release per the ≤ 5 mSv rule (≤ 33 mCi I-131 or ≤ 7 mR/hr at 1 m surrogates; written instructions if > 1 mSv). Premedication is agent-defining: amino-acid renoprotection (PRRT), antiemetics, thyroid blockade (MIBG/I-131), rituximab pre-dose (RIT).
Two sequencing/monitoring rules recur: avoid Ra-223 with abiraterone+prednisone (ERA-223) and follow ALP (PSA unreliable) for Ra-223; and follow dosimetry-guided dosing where the therapeutic ratio is tight (Y-90 mandatory; increasingly explored for PRRT). Post-therapy imaging (I-131 WBS, Y-90 PET/bremsstrahlung, Lu-177 SPECT/CT) confirms delivery and often changes management.
Related Pages
- Therapies: ¹⁷⁷Lu-DOTATATE, ¹⁷⁷Lu-PSMA-617, ²²³Ra-dichloride, Y-90 radioembolization, I-131-MIBG, radioimmunotherapy.
- Reference: MIRD dosimetry (worked), quantitative thresholds & decision cutoffs, radiation safety & patient release.
Figure / Diagram Suggestions
- A therapy protocol card grid (agent / activity / schedule / premed / monitoring / release).
- A selection → treat → post-therapy imaging workflow common to theranostics.
Self-Check
Q1. State the standard ¹⁷⁷Lu-DOTATATE regimen and its key premedication.
Answer: 7.4 GBq (200 mCi) every 8 weeks × 4 cycles, with an amino-acid (arginine/lysine) renal-protection infusion (+ antiemetics).
Q2. What must precede every radionuclide therapy administration under US NRC rules?
Answer: A written directive (required for any therapy dose; and for I-131 > 30 µCi).
Q3. What is the Ra-223 regimen, which combination is contraindicated, and which marker is followed?
Answer: 55 kBq/kg IV every 4 weeks × 6; avoid abiraterone + prednisone (ERA-223); follow alkaline phosphatase (PSA is unreliable).
Q4. Give the US NRC patient-release limit and two common surrogate criteria.
Answer: TEDE to others ≤ 5 mSv; surrogates ≤ 33 mCi I-131 retained or ≤ 7 mR/hr at 1 m, with written instructions if projected dose > 1 mSv.
Evidence & sources
https://nuc.med/therapy-administration-protocols/ Report an issue