Ultralow dose computed tomography attenuation correction for pediatric PET CT using adaptive statistical iterative...

Area of Science:

• Medical Imaging
• Radiology
• Nuclear Medicine

Background:

• Pediatric Positron Emission Tomography CT (PET CT) combines anatomical and functional imaging.
• Computed Tomography (CT) attenuation correction (CTAC) is crucial for PET quantification.
• Reducing radiation dose in pediatric CTAC is a significant clinical goal.

Purpose of the Study:

• To develop and evaluate ultralow dose CT acquisition protocols for pediatric PET CT.
• To assess the impact of reduced CT dose on quantitative PET and CT measurements.
• To maintain diagnostic image quality for hybrid PET CT imaging in children.

Main Methods:

• Investigated ultralow dose CTAC protocols (10-35 mA s) on a GE Discovery 690 PET CT scanner.
• Analyzed CT quantitation (noise, resolution, CT numbers) using tissue substitutes and reduced dose index.
• Utilized 100% adaptive statistical iterative reconstruction (ASiR) to mitigate noise.
• Evaluated PET image metrics (SUVbw, uniformity, spatial resolution) and compared radiation dose and noise in patient data.

Main Results:

• CT numbers remained within 10% for up to 90% CT dose reduction.
• No significant changes were observed in PET image quantitative metrics (SUVbw, uniformity, spatial resolution).
• Achieved 62%-86% relative CTAC dose reduction in patients, with increased but statistically insignificant noise levels.

Conclusions:

• Ultralow dose CTAC protocols are feasible for pediatric PET CT.
• Adaptive statistical iterative reconstruction (ASiR) enables substantial CT dose reduction.
• Maintained image quality for accurate PET/CT colocalization, crucial for pediatric diagnostics.