Knowledge Hub · MUCHA Nova Multi-Channel Analyser
A radiochemical-purity check tells you the chemistry worked. A gamma spectrum tells you the radionuclide you labelled with is what you think it is. For theranostic-era isotopes — Lu-177, Ga-68, F-18 from a cyclotron — both failure modes are real. This page is why every batch record carries both, and what AERB inspection reads off them.
Why this matters
What γ-spec catches that %RCP misses
A radiochemical-purity check (radio-TLC or radio-HPLC) measures whether the activity is bound to the intended radiopharmaceutical. It does NOT measure whether that activity is the radionuclide you intended. A Lu-177 batch contaminated with Lu-177m has the same %RCP — same chromatogram, same TLC strip — but a different gamma spectrum. Only the multi-channel analyser distinguishes them.
Based on: IAEA TRS 466 — Quality Assurance for PET and PET/CT Systems; Eur.Ph. radiopharmacy monographs (radionuclidic-purity sections).
Read source ↗Mo-99 breakthrough in Tc-99m eluate
Mo-99 / Tc-99m generators slowly leak the long-lived Mo-99 parent into the eluate. Eur.Ph. specifies a 0.1 % activity limit at expiry. The dose-calibrator shielded-attenuator method gives an integrated number — but the MCA gamma spectrum resolves the 140 keV Tc-99m photopeak from the 740 / 780 keV Mo-99 lines directly. The spectrum is faster, more sensitive and produces a per-eluate audit-trail record.
Based on: Eur.Ph. monograph 0124 / 0283 — Sodium pertechnetate (Tc-99m); IAEA technical guidance.
Read source ↗Ge-68 breakthrough in Ga-68 eluate
Ge-68 / Ga-68 generators leak the long-lived Ge-68 parent (t½ 271 d) into the eluate. Eur.Ph. specifies a < 0.001 % activity limit at expiry. The breakthrough check is a delayed-spectrum measurement — let Ga-68 decay (t½ 68 min) and measure the residual gamma spectrum. Any Ge-68 contamination shows up as the persistent 511 keV annihilation line after Ga-68 has decayed away. The MCA carries the method; every Ga-68 batch can carry the breakthrough check on its release record.
Based on: Eur.Ph. monograph 2482 — Gallium-68 chloride; IAEA TRS 466 Ga-68 PET tracer QC chapter.
Read source ↗Lu-177m and the n.c.a. claim
No-carrier-added Lu-177 is produced via Yb-176 → Lu-177 chemistry with downstream separation; carrier-added Lu-177 is produced by direct Lu-176(n,γ) activation and inevitably contains Lu-177m (160 d half-life). Radio-TLC %RCP looks identical. Only the gamma spectrum tells them apart — Lu-177m sits at 228 keV while pure Lu-177 sits at the 113 / 208 keV doublet. The nuclide-identity check is what distinguishes n.c.a. supply from c.a. on the batch record.
Based on: EANM Technologist Guide — Quality Control of Radiopharmaceuticals; ICRP Publication 107 nuclear-decay data.
Read source ↗NaI(Tl) standard + HPGe HR
NaI(Tl) scintillation gives ~7 % FWHM at 662 keV — fast acquisition, good detection efficiency, sufficient for the daily release programme (Mo-99, Ge-68, Lu-177m thresholds well separated from the primary lines). HPGe gives ~0.2 % FWHM — necessary when close-lying lines need resolving (cyclotron co-productions, fingerprint nuclide identification). The HR chassis adds the HPGe option without changing the operator workflow or the audit trail.
Based on: IAEA Quality Assurance for Radioactivity Measurement in Nuclear Medicine; HPGe and NaI(Tl) detector physics references.
Read source ↗SQL audit-trail database
AERB inspection reads the chain: which spectrum was acquired, against which library, what the threshold check returned, who signed the release. The SQL audit-trail database captures all of it — per-spectrum file, per-operator signature, per-method version, per-calibration record. Inspection-time export gives the inspector a per-batch dossier; no parallel paper log to reconcile.
Based on: US FDA 21 CFR Part 11 — Electronic Records, Electronic Signatures; AERB Safety Code for Nuclear Medicine Facility.
Read source ↗IAEA, Eur.Ph., EANM and AERB documents that anchor the radionuclidic-purity QC workflow.
IAEA technical report covering PET radiopharmacy QC including paired radiochemical-purity and radionuclidic-identity expectations.
European Pharmacopoeia general + per-isotope monographs defining radionuclidic-purity thresholds.
EANM technologist-facing guide on radiopharmaceutical QC including gamma-spectrometric nuclide-identity methods.
Indian regulatory framework for nuclear-medicine facility licensing including hot-lab QC and release-record expectations.