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Explore the various minimally invasive needle biopsy modalities for diagnosing breast abnormalities, including fine needle aspiration cytology (FNAC) and automated needle biopsy. Learn about the steps involved in stereotactic breast biopsy and the importance of proper patient positioning.
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CHAPTER 20 Minimally Invasive Needle Breast Biopsy
BIOPSY MODALITIES • Clinical (palpable) • Image guided • Ultrasound • MRI • Stereotactic (x-ray)
BREAST BIOPSY • Surgical excision @ 30% • Percutaneous methods @ 70%
PERCUTANEOUS BREAST BIOPSY • Fine needle aspiration cytology (FNAC) • Automated needle biopsy (core biopsy)
AUTOMATED NEEDLE BIOPSY • AKA: Core biopsy; stereo; stereotactic • 8- to 14-gauge needle/probe • Spring-loaded or vacuum-assisted • Procedure completed in <1 hour • More definitive diagnosis compared with FNAC
STEREOTACTIC BREAST BIOPSY • As an accessory attached to mammography unit • Dedicated prone stereotactic table
STEP 1: SCOUT IMAGE • Ensure the ROI is inside the biopsy window.
STEP 2: ACQUIRE STEREO PAIR • X-ray tube moves +15°and –15° • Line drawing of a stereo pair • X-ray stereo pair image
STEP 3: TARGET THE ROI • Physician selects the area to be biopsied. • Computer calculates ROI location co-ordinates and transmits to biopsy device.
CO-ORDINATE SYSTEM • Cartesian • X, Y, Z • Polar • H, V, D
STEP 4: PREFIRE POSITION • Biopsy device stops just short of the ROI.
STEP 4: PREFIRE POSITION • “Firing” biopsy device ensures piercing of ROI. • The “fired” distance is the stroke of the biopsy device.
STEP 6: TISSUE MARKER CLIP • Tissue marker clip is deployed into biopsy cavity. • If ROI is positive for cancer, clip directs physicians to exact location of tumor.
STEP 7: SPECIMEN • Collection basket contains specimen cores • X-ray of specimen
STROKE MARGIN • Before biopsy device is inserted into breast, ensure positive stroke margin. • Negative stroke margin may result in biopsy device passing through the breast and striking breast platform. • This may bend the needle and make removal very difficult.
PATIENT POSITIONING • Location of ROI determines positioning approach • Shortest skin-to-lesion distance
ALTERNATE POSITIONING A. Usually a superior lesion is biopsied in the CC position. However, in this case, ROI is not seen on image. B. Several alternative positions are available to visualize ROI.