Radiation Exposure to Patients and Others During Therapy for Pediatric Neuroblastoma With Lu-177-DOTATATE

Purpose: This study evaluated Lutetium-177-(DOTA°,Tyr 3 ) octreotate (Lu-177-DOTATATE) clearance in pediatric patients with neuroblastoma and assessed the effective doses received by patients, family caregivers, and medical staff during therapy. Patients and Methods: Twenty-three children (3–13 y) who received Lu-177-DOTATATE between 2023 and 2024 were enrolled. External dose rates were measured at 0, 1, 2, 4, 6, 24, 48, and 96 hours post-administration to estimate patients’ Lu-177-DOTATATE retention rate, the effective half-life, and the maximum cumulative effective dose around patients. Whole-body and red-marrow absorbed doses were calculated based on multi-time-point whole-body planar and SPECT/CT imaging using HERMES Dosimetry software. Whole-body effective doses to family caregivers and medical personnel were measured using thermoluminescence dosimeters (TLDs), and effective finger doses for medical staff were measured using ring TLDs. Results: The mean administered activity was 3.687±1.545 (range, 1.469–7.368) GBq. Whole-body retention rates at 1–96 hours post-administration ranged from 72.0% to 10.0%, with 99% clearance expected within 11 days. Clearance followed a biexponential decay model, with estimated effective half-lives of 1.4±0.8 and 52.3±18.6 hours for the fast and slow phases, respectively, at 2 m. Estimated maximum cumulative effective doses (within 11 days) at 1 and 2 m were 0.442±0.174 and 0.138±0.058 mSv, respectively. Absorbed doses for children were 0.159±0.076 mGy/MBq (whole body) and 0.611±0.416 mGy/MBq (red-marrow). Whole-body effective doses to family caregivers averaged 0.244±0.063 (range, 0.150–0.390) mSv. The whole-body and finger-effective doses to the radiopharmacists were 3.7±1.8 and 155.3±73.0 μSv/patient, respectively. The mean of whole-body and the median ( P 25 , P 75 ) of finger-effective doses to nurses were 4.7±1.4 μSv/patient and 16.7 (10, 470) μSv/patient, respectively. Conclusions: Lu-177-DOTATATE was rapidly cleared in children with neuroblastoma. Radiation exposure to others was below personal dose limits.