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

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This study evaluated Lutetium-177-(DOTA°,Tyr3) 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. Twenty-three children (3-13y) 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. 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 2m. Estimated maximum cumulative effective doses (within 11 days) at 1 and 2m were 0.442±0.174 and 0.138±0.058mSv, respectively. Absorbed doses for children were 0.159±0.076mGy/MBq (whole body) and 0.611±0.416mGy/MBq (red-marrow). Whole-body effective doses to family caregivers averaged 0.245±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±73.0μSv/patient, respectively. The mean of whole-body and the median (P25, P75) of finger-effective doses to nurses were 4.7±1.4μSv/patient and 16.7 (10, 470) μSv/patient, respectively. Lu-177-DOTATATE was rapidly cleared in children with neuroblastoma. Radiation exposure to others was below personal dose limits.