Supplementary file 1_Modelling image quality over extended [18F]FDG uptake times for low-dose positron emission mammography.docx

Introduction<p>This study investigated the effect of [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) uptake time on image quality in low-dose positron emission mammography (PEM) using kinetic modelling.</p>Methods<p>Fifteen malignant lesions from thirteen women newly diagnosed with breast cancer were imaged using low-dose [¹⁸F]FDG PEM. Tumour and normal breast tissue time-activity curves (TACs) were generated using a population-based arterial input function (AIF) and a two-tissue compartmental model.

Modelling was performed at [¹⁸F]FDG doses of 1, 2, 5, and 10 mCi (37, 74, 185, and 370 MBq), and image quality was assessed using contrast-to-noise ratio (CNR) over a 6-hour uptake period.</p>Results<p>Extending uptake times beyond the 1-hour clinical standard significantly improved CNR across all doses, with comparable proportional gains. Relative to 1 hour post-injection, CNR increased by approximately 30% at 1.5 hours, 53% at 2 hours, and 77% at 3 hours, although uncertainty widened at 3 hours and beyond, particularly at the lowest dose (1 mCi).