An apparatus for positron emission mammography-guided breast biopsy

Positron emission mammography (PEM) is a new technique that is used to obtain planar images of the breast to detect potentially radiotracer-avid tumors. To increase this method´s diagnostic accuracy, it may necessary to acquire tissue samples from these lesions. The purpose of this study was to develop and investigate a novel method for performing PEM-guided stereotactic breast biopsy. The technique utilizes a new, trigonometric algorithm to stereotactically calculate the position of lesions. To test the accuracy and precision of the guidance method, a small point source of positron-emitting radionuclide (¹⁸ F) was placed at five known locations within the field-of-view of the imager. Images at ±15 degrees were obtained and used to calculate the positions of the source. The capability of the PEM system to biopsy breast lesions was evaluated by simulating the lesion. The use of PEM in conjunction with “biopsy” of two gelatin spheres (12 and 6 mm diameter) containing FDG FDG (a known radiotracer used to image breast cancer) placed in a gelatin block (4 cm thick) also containing (simulating a compressed breast). The tumor-to-background concentration ratio was 8.4:1, which is a typically reported value for FDG-PET studies. The positions of the point source were successfully calculated to within 0.6 mm of their true positions with an error of ±0.4 mm. This accuracy and precision is sufficient for proper placement of a biopsy needle in a lesion. Samples of both gelatin spheres were successfully technique shows promise for use in guiding stereotactic biopsy of radiotracer-avid breast lesions detected with PEM