Overview
IEC TR 61948-2:2001 is a technical report from IEC that defines routine tests for quality control of single-photon scintillation cameras with parallel-hole collimators used in planar scintigraphy and SPECT imaging. The report focuses on practical, repeatable checks that users should perform to monitor ongoing performance and detect degradation from the reference data established at acceptance testing. It complements acceptance-test methods described in IEC 60789 and IEC 61675‑2.
Key topics and technical requirements
- Scope: single photon scintillation cameras (parallel-hole collimators) for planar and tomographic (SPECT) use.
- Test environment: Measurements should be made with the clinical analyzer energy-window setting and at count rates not exceeding 20 000 counts/s.
- Reference data: Results are compared to REFERENCE DATA collected at ACCEPTANCE TESTING; deviations require updating correction factors or servicing.
- Routine tests covered (planar and SPECT):
- Energy window setting - verify at least daily for each radionuclide (use a point source in air to minimize scatter).
- Background count rate - determine for commonly used low-energy windows to detect contamination or malfunctions.
- Sensitivity check - measure count rate with a reference source (<200 keV) in a fixed geometry.
- Non‑uniformity:
- Intrinsic (without collimator) and system (with collimator) non‑uniformity checks.
- Qualitative planar checks: >3 000 counts/cm²; quantitative checks: ≥20 000 counts/cm² (to obtain statistically reliable results).
- SPECT non‑uniformity testing requires a flood source and photon flux uniformity within ±1% over ~1 cm² areas, with ≥20 000 counts/cm².
- Pixel size, resolution/linearity (planar) and detector head tilt, center of rotation, tomographic non‑uniformity (SPECT).
- Documentation: All routine-test outcomes must be documented and trended against reference values.
Practical applications and users
This TR is intended for professionals responsible for nuclear medicine quality assurance and equipment maintenance:
- Medical physicists - design and supervise routine QC programs and interpret trends.
- Clinical engineers and service engineers - perform tests, calibrations, and corrective servicing.
- Nuclear medicine technologists - carry out daily checks (e.g., energy window, background).
- Manufacturers and QA managers - implement SOPs and integrate routine-test requirements into device lifecycle procedures.
Practical benefits include improved image quality, reliable quantitative SPECT/planar measurements, early detection of detector or collimator faults, and maintenance of patient-safety and regulatory compliance.
Related standards
- IEC 60788 (Terminology)
- IEC 60789 (Acceptance tests for Anger-type gamma cameras)
- IEC 61675‑2 (SPECT characteristics and test conditions)
- IEC 61675‑3 (Gamma camera based wholebody imaging systems)
Keywords: IEC TR 61948-2, scintillation cameras, SPECT routine tests, nuclear medicine quality control, energy window, non-uniformity, detector head tilt, center of rotation, IEC 60789.