MEASURAND SIR equivalent activity of Ac-225
Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui (k =2), both expressed in kBq.
Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui (k =2), both expressed in kBq/MBq.
MEASURAND SIR equivalent activity of Ac-225
Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui (k =2), both expressed in kBq.
| LABi | Di | Uneg,i | Upos,i | |
|---|---|---|---|---|
kBq |
kBq |
kBq |
||
| PTB | -280 | 560 | ||
| POLATOM | 280 | 560 |
Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui (k =2), both expressed in kBq/MBq.
| LABi | Di | Uneg,i | Upos,i | |
|---|---|---|---|---|
kBq/MBq |
kBq/MBq |
kBq/MBq |
||
| PTB | -3.7 | 7.5 | ||
| POLATOM | 3.8 | 7.5 |
| Metrology area, Sub-field | Ionizing Radiation, Section II (Measurement of Radionuclides) |
| Description | Activity of radionuclide Ac-225 |
| Time of measurements | 2024 - 2025 |
| Status | Measurements in progress |
| Measurand | Activity of 225Ac per unit mass |
| Transfer device | Ampoules of Ac-225 |
| Comparison type | Key Comparison |
| Consultative Committee | CCRI (Consultative Committee for Ionizing Radiation) |
| Conducted by | EURAMET (European Association of National Metrology Institutes) |
| RMO Internal Identifier | EURAMET Project No 1682 |
| Comments | Key Comparison of Ac-225 in the framework of the AlphaMet project: Comparison of measurements standards of Ac-225 between seven radionuclide metrology institutes in the framework of the European project AlphaMet started in 2023 for a duration of three years. The aim of this project is to address metrological challenges of emerging alpha-emitting radiopharmaceuticals investigated in pre-clinic and clinic centres for Targeted Alpha Therapy. The goal is also to support the implementation of end-to-end traceability for alpha therapies before wide routine adoption. Ra-225 as a salt shipped from CERN-MEDICIS. The chemical separation for the preparation of the ampoules with Ac-225 solution carried out at NPL. The shipment of ampoules to participants is performed by NPL. |
| Pilot institute |
LNE-LNHB
Commissariat à l'énergie atomique / Laboratoire National Henri Becquerel France |
| Contact person | Christophe BOBIN +33 169082964 |
| Pilot laboratory | |
|---|---|
| LNE-LNHB |
Commissariat à l'énergie atomique / Laboratoire National Henri Becquerel, France, EURAMET |
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MEASURAND SIR equivalent activity of Ac-225
The SIR reference value for this radionuclide is xR = 74 800 kBq, with a standard uncertainty uR = 280 kBq.
xR is calculated by using the power-moderated weighted mean of the SIR results (see Section 4.1 of the Final Report). The value xi is taken as the equivalent activity for a laboratory i.
The degree of equivalence of each laboratory with respect to the reference value is given by a pair of terms: Di = (xi - xR) and Ui its expanded uncertainty (k = 2), both expressed in kBq, and Ui = 2((1 - 2wi)ui2 + u2R)1/2, where wi is the weight of laboratory i contributing to the calculation of xR.
The Degrees of equivalence are also given in relative terms by Di = (xI - xR) /xR and its expanded uncertainty Ui at a 95 % level of confidence, both expressed in kBq/MBq.
MEASURAND SIR equivalent activity of Ac-225
xi equivalent activity measured by the SIR for a laboratory i, Labi
ui combined standard uncertainty of xi
| Labi | xi | ui | Date of measurement | |
| kBq | kBq | |||
| PTB | 74520 | 200 | 2019-06-21 | |
| POLATOM | 75080 | 210 | 2021-07-06 |
