Fig. 2

Mediolateral oblique views of the right breast from mammography (a) and MBI (b, c) obtained in a premenopausal study participant taking 5 mg tamoxifen per day for 30 days. The pre-tamoxifen MBI image (b) obtained on the first day of her menstrual cycle shows moderate background parenchymal uptake (BPU) with quantitative BPU of 1.9, corresponding to the areas of fibroglandular tissue on the mammogram. The post-tamoxifen MBI image (c), also obtained on the first day of menstrual cycle, shows minimal to mild BPU, with quantitative BPU of 1.3, a 31% decline from the pre-tamoxifen MBI