Anat Biegon
Stony Brook University, USA
Title: High contrast visualization of breast cancer lesions with [11C] vorozole PET
Biography
Biography: Anat Biegon
Abstract
More than a half of breast tumors are known to overexpress estrogen synthase (aromatase, Cyp19A gene product); and aromatase inhibitors are the mainstay of current hormonal adjuvant therapy in breast cancer. Vorozole is a potent aromatase inhibitor which was labeled with carbon11 and recently used to image aromatase with PET in healthy men and women. Here we describe the first case of breast cancer to be imaged with this tracer. A 68 year old woman recently diagnosed with stage 4 invasive lobular carcinoma was given 7.3 mCi [11C]vorozole intravenously. Forty minutes after injection, she was positioned in the prone position in a high resolution PET/CT (Siemens) scanner; with both breasts in the field of view. PET emission data were collected over a 50 minute period. The PET images revealed a large area of very high intensity in the left breast; corresponding in location and size to the diagnostic mammography; and multiple smaller regions with high intensity in the sternum and thoracic spine. The dynamic study included 5 frames of 10 min. duration each. Regions of interest (ROIs) were drawn with PMOD over the first frame and the corresponding time-activity curves were obtained. ROIs were placed in 2 locations of the carcinoma, in the breast adjacent to the tumor and in the contralateral breast. The ratio of tracer uptake in the tumor to the uptake in the same location in the contralateral breast ranged from 4.8 to 7.2 in the first frame (40-50 min). Both absolute uptake and ratio of tumor to contralateral breast decreased over time between 50 and 90 minutes post injection; suggesting a short (10-20min) acquisition may be sufficient. The [11C]vorozole PET image compares favorably with other imaging studies performed on the same patient, including FDG and MRI; supporting further investigation and optimization of this tracer in breast cancer.