Performance evaluation of a clinical SPECT system with multifocal collimator for brain studies

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Radiology

Background:

• Single-photon emission computed tomography (SPECT) is crucial for diagnosing dementia by evaluating brain function.
• Current SPECT head examinations can cause patient discomfort due to collimator contact with shoulders.
• The novel multifocal high-resolution collimator (SMARTZOOM high resolution and extended [SZHRX]) offers potential to mitigate this discomfort by maintaining image quality at increased distances.

Purpose of the Study:

• To evaluate the image quality of the multifocal collimator (SZHRX) in SPECT brain imaging.
• Assess spatial resolution, sensitivity, uniformity, and contrast using various phantoms and nuclides.
• Determine the feasibility of using SZHRX to reduce patient discomfort during head examinations.

Main Methods:

• Utilized ^99mTc and ¹²³I nuclides in phantoms imaged with SZHRX at rotation radii of 24-34.5 cm.
• Compared SZHRX performance against standard low-energy high-resolution (LEHR) and low-medium energy general purpose (LMEGP) collimators at a 14 cm radius.
• Quantified spatial resolution (Full-Width Half-Maximum), sensitivity, uniformity (Coefficient of Variation), and %contrast for each collimator and condition.

Main Results:

• SZHRX demonstrated acceptable spatial resolution and uniformity, even at increased rotation radii.
• Sensitivity of SZHRX increased with distance, showing higher values than LEHR for ^99mTc.
• Image quality metrics like %contrast varied with distance and nuclide, with SZHRX showing comparable or slightly reduced contrast compared to standard collimators in some instances.

Conclusions:

• The SZHRX collimator enables high spatial resolution and uniformity in SPECT imaging, even with extended rotation radii.
• This technology can potentially improve patient comfort during head examinations without significant compromise in image quality.
• The findings support the future clinical application of SZHRX for enhanced SPECT brain imaging.