Accuracy of quantitative reconstructions in SPECT/CT imaging.

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Radiochemistry

Background:

• Quantitative SPECT/CT imaging is crucial for accurate diagnosis and treatment monitoring.
• Existing reconstruction methods may face challenges in precise activity quantification for various isotopes.
• The Ordered Subset Expectation Maximization with Accurate Post-Reconstruction Data Interpolation (OSEM-APDI) method aims to improve accuracy.

Purpose of the Study:

• To quantitatively assess the accuracy of the OSEM-APDI reconstruction method using SPECT/CT.
• To evaluate the performance of the OSEM-APDI method across multiple clinically relevant isotopes (Tc-99m, In-111, I-123, I-131).
• To determine the impact of various corrections on the overall accuracy of SPECT/CT reconstruction.

Main Methods:

• Phantom studies were conducted on a SPECT/low-dose multislice CT system.
• An anthropometric Thorax phantom was filled with non-radioactive water and contained two radioactive sources.
• Clinical acquisition protocols were used, and corrections for attenuation, scatter, collimator blurring, and septal penetration were applied and evaluated.

Main Results:

• The OSEM-APDI reconstruction method was applied to Tc-99m, In-111, I-123, and I-131 isotopes.
• Activity estimations were performed with varying levels of applied corrections.
• The most comprehensive set of corrections yielded activity estimation errors within 3-5% for all tested isotopes.

Conclusions:

• The OSEM-APDI reconstruction method demonstrates high quantitative accuracy for SPECT/CT imaging.
• Comprehensive corrections are essential for achieving precise activity quantification across multiple isotopes.
• This method holds promise for improving diagnostic and therapeutic assessments in nuclear medicine.