Breast tumor imaging using a tiltable head SPECT camera

An axially Tiltable-Head SPECT (TH-SPECT) system with 2 heads was used to image fillable breast and torso phantoms containing multiple lesions at various tilt angles. Breast, liver, and myocardial activity were included in order to simulate direct contamination and Compton scattering expected in clinical scans. High count planar images were acquired for comparison with TH-SPECT, and the TH-SPECT data was reconstructed using an OS-FM algorithm which accounted for the tilted geometry. In order to characterize axial blurring effects inherent with TH-SPECT reconstructions, two cylindrical disk Defrise phantoms, one large Defrise phantom and one mini-Defrise phantom placed inside the fillable breast phantom, were imaged at various tilt angles. Reconstructions of the combined fillable breast and torso phantoms containing two 1.15 ml lesions, one centered axially and one proximal to the anterior chest wall within the breast, were most clearly visible in the 30° reconstructed TH-SPECT images compared to the high-count planar images, providing lesion SNR and contrast improvements of nearly three times