Loading
Life sciences · Journal article
Annals of Nuclear Medicine · October 12, 2026
No summary has been generated for this record yet. What follows is drawn from its source metadata only.
Journal article.
No findings were extractable from the material analysed.
Safety was not reported in the material analysed. Check the source before drawing any conclusion about harm.
The source did not state who this applies to in practice.
Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.
This record has not been graded across any dimension yet. Treat the label above as provisional and read the source.
What is missing. This record has no bottom line, key findings, reported figures, evidence dimensions. That is a gap in the analysis, not a judgement about the study.
Abstract Objective Pre-therapy blood–marrow dosimetry for ¹³¹I treatment of differentiated thyroid cancer (DTC) requires serial imaging and blood sampling, limiting clinical adoption. When blood data are unavailable, operators fall back to fixed or imaging-only prescribing, usually without an explicit uncertainty bound. We characterise the cohort electron blood self-dose fraction (β frac ) in a single-centre ¹²⁴I PET cohort and quantify the uncertainty incurred by substituting that reference for patient-specific blood data. Methods Retrospective single-centre analysis of 18 pre-therapy ¹²⁴I PET courses in 15 DTC patients with paired serial venous blood-counting, all prepared by thyroid-hormone withdrawal. Time–activity curves were fitted in the ¹³¹I therapy frame following the EANM Standard Operational Procedure, separating D blood into its electron (β, blood self-dose) and photon (γ, body cross-fire) components. The substitution uncertainty was propagated analytically, then validated against patient-level errors by leave-one-patient-out cross-validation. Results The cohort β fraction was 84.3 ± 4.8% across 18 courses (mean ± SD; median 85.4%; 95% CI 82.0–86.7%), and 84.4 ± 4.6% over the 15 patients. The β fraction decreased with body weight (− 0.113 pp/kg, p = 0.019), although not significantly when reduced to one value per patient ( p = 0.118); the association is therefore exploratory. Substitution gave a per-patient 1-σ uncertainty on the imaging-only D blood estimate of ≈ 30%. Under leave-one-patient-out cross-validation the mean absolute percentage error was 26.3% and the RMSE 32.7%, with 12 of 18 courses within ± 30% of their reference. Conclusions A cohort β fraction of 84.3 ± 4.8% is proposed as a fall-back reference for blood-free prescribing in DTC radioiodine therapy. Because the estimator’s error is multiplicative on the estimate, a prescribing cap must come from the lower tail of that error, giving approximately 1.0–1.2 Gy in this cohort. No 95% coverage is demonstrated at this sample size, and the cap is offered as an exploratory observation requiring local confirmation rather than a validated threshold. The decomposition is imaging-modality agnostic for ¹³¹I clearance studies and therefore potentially applicable to low-dose ¹³¹I SPECT, although no SPECT data were analysed here.