Phantom Validation of Tc-99m Absolute Quantification in a SPECT/CT Commercial Device

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Radiopharmaceuticals

Background:

• Absolute quantitative imaging is increasingly available in commercial SPECT/CT devices, similar to PET.
• Accurate quantification is crucial for effective nuclear medicine diagnostics.

Purpose of the Study:

• To evaluate the quantitative accuracy of activity recovery in SPECT/CT.
• To assess the impact of reconstruction parameters and count statistics on accuracy using various phantoms.

Main Methods:

• Quantitative 99mTc-SPECT/CT scans were performed on uniform cylindrical, NEMA/IEC, and anthropomorphic phantoms.
• Acquisitions covered a range of background activity concentrations (2-80 kBq/mL).
• Image reconstruction utilized an iterative conjugate gradient algorithm, with varying iteration numbers.

Main Results:

• Absolute activity and concentration measurements were within 10% of expected values across all phantoms.
• Recovery coefficients and hot contrast were largely independent of count statistics.
• Accurate results were achieved with 16 iterations for inserts >22 mm, comparable to PET levels.

Conclusions:

• The evaluated SPECT/CT system demonstrates high quantitative accuracy for activity recovery.
• Performance metrics are comparable to contemporary PET/CT systems, indicating effective integration of corrections and modeling.