An apparatus for positron emission mammography guided biopsy

Positron emission mammography (PEM) is a new technique that is used to obtain planar images of the breast to detect potentially cancerous radiotracer-avid tumors. To increase diagnostic accuracy, it may be desirable to use minimally invasive methods (core biopsy, for example) to obtain tissue samples from lesions optimally detected with PEM. The purpose of this study is to develop and investigate a novel method for performing PEM-guided stereotactic breast biopsy. The PEM system consisted of two square (10 cm×10 cm)-detector arrays of discrete (3 mm×3 mm ×10 mm) blocks of GSO. Scintillation light was collected by arrays of 16 position-sensitive PMTs. The detector heads were mounted 18 cm apart on a Lorad stereotactic biopsy table. The authors´ stereotactic technique utilizes two PEM images acquired at symmetric angles. A trigonometric algorithm is then used to calculate the position of the object in 3-dimensions. To test the accuracy and precision of the guidance method, a small point source of FDG was placed at five known locations within the field-of-view of the imager. In addition, a simulated stereotactic biopsy was performed on a breast phantom. The positions of the point sources were successfully calculated to within 0.6 mm of their true positions with an error of ±0.4 mm. The simulated biopsy procedure was successful in acquiring samples from the two simulated lesions. Thus, this technique shows promise for use in guiding stereotactic biopsy of radiotracer-avid breast lesions detected with PEM