The value of scintigraphic imaging using 99mTc labeled poly(ethyleneglycol) (PEG) -liposomes for detecting invasive pulmonary aspergillosis at different stages of the disease was investigated in a rat model. At 24, 48, 72, 120 and 168 h after fungal inoculation scintigraphic images were obtained and biodistribution of the radiolabel was determined. Findings were compared with serum galactomannan detection and other parameters of progression of fungal infection. At 48 h liposomal uptake in the infected left lung was increased significantly and 82% of the scintigraphic images was assessed positive. Serum galactomannan was only detected at 72 h and later. Liposomal uptake in the infected left lung increased over time and was significantly correlated with both the size of the pulmonary hemorrhagic lesion and the levels of circulating galactomannan. It was concluded that scintigraphic imaging using 99mTc-PEG-liposomes allows early detection of invasive pulmonary aspergillosis in this model, and that liposomal uptake in the infected lung was strongly associated with the severity of the disease.