A dedicated breast-PET/CT scanner: Numerical observer study of lesion detection

Area of Science:

• Medical Imaging
• Radiology
• Nuclear Medicine

Background:

• Dedicated breast-specific positron emission tomography/computed tomography (BPET/CT) systems aim to improve cancer detection in women with radiodense breasts.
• Unlike mammography, PET imaging is unaffected by X-ray absorption in dense breast tissue.
• Limitations of breast PET include lower spatial resolution and moderate radiotracer uptake in lesions.

Purpose of the Study:

• To assess the lesion detection capabilities of a novel BPET/CT scanner developed at West Virginia University.
• To explore the performance of PET-based imaging for breast cancer diagnosis.

Main Methods:

• Utilized a BPET/CT system with LYSO scintillator arrays and cone-beam CT with a pulsed X-ray source.
• Employed an 18F-fluorodeoxyglucose (FDG) phantom with simulated lesions (3-10 mm) at varying target-to-background ratios (TBRs).
• Applied numerical model observers (Laguerre-Gauss channelized Hotelling observer and non-prewhitening matched filter) to analyze PET image data.

Main Results:

• The smallest detectable simulated lesion was approximately 3 mm in diameter at a TBR of 6:1.
• Simulated lesions of 4 mm and larger demonstrated good to excellent detection likelihood across all tested TBRs.
• CT density maps were used for photon attenuation and Compton scatter correction in BPET data.

Conclusions:

• The study identified the detection capabilities and limitations of the dedicated breast-PET/CT scanner.
• The system's ability to detect small simulated FDG-avid lesions suggests potential for clinical application.
• The methodologies used can be applied to assess the detectability of other PET/CT scanners.