Saxsons Group

Knowledge Hub · Dose Calibrator QA Sources

One four-isotope set — every clinical photon energy covered.

The canonical dose-calibrator QA reference set bundles Ba-133, Co-57, Cs-137 and Co-60 — spanning 81 keV to 1.332 MeV. Together they cover every clinical photon energy the calibrator will see in service, and the NIST-traceable certificate on each makes the annual physicist accuracy review defensible at AERB inspection.

Why this matters

Three things the four-isotope set delivers

Four isotopes, one set

Ba-133, Co-57, Cs-137, Co-60 span 81 keV to 1.332 MeV

Ba-133 (81 keV) at the low end, Co-60 (1.173/1.332 MeV) at the high end, with Co-57 (122 keV) and Cs-137 (662 keV) in between. The four span the full photon-energy range of clinical radionuclides — one set verifies the dose calibrator at every clinical energy.

Based on: Source manufacturer set spec.

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NIST traceability

A defensible chain back to the US national standard

Every certificate is calibrated by direct comparison to NIST. The audit chain runs source certificate → in-house calibration log → AERB inspection dossier — three links, all NIST-anchored, defensible at regulatory review and NABH / JCI accreditation.

Based on: AERB Safety Code for Nuclear Medicine Facility.

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Annual accuracy + linearity

The set anchors the annual physicist review

AAPM TG-181 and TG-211 expect an annual NIST-traceable accuracy test on every clinical dose calibrator. The four-isotope set is the reference — measured activity must match each certificate within ±10%. The same set supports linearity testing where decay-based linearity is impractical.

Based on: AAPM TG-181 / TG-211 guidance.

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Scope of this page

The reference-source set is the QA anchor; the QA programme is the radiopharmacy's. Cadence, action thresholds and trending logs sit with the site SOP — the source set supplies the NIST-traceable ground truth inside that programme.