Stereotactic Biopsy Using Digital Breast Tomosynthesis

Introduction

Hello everyone, and welcome to this course. Today we are going to talk about stereotactic breast biopsies using digital breast tomosynthesis. I am Mohammad Eghtedari, and I am one of the faculty in breast imaging at the University of California in San Diego. Welcome to this course.

Objectives

My goal during this course is to review the method that we use for a fast and efficient breast biopsy under tomographic guidance. I don't have any financial disclosure relevant to this talk.

Topics

Preparation and Planning

For any biopsy, it is crucial to:

  • Review images prior to the day of the procedure to understand the target area.
  • Be familiar with the instruments that will be used during the procedure. Unexpected equipment changes should be avoided.
  • Plan the approach and choose the appropriate needle type based on the target's location.
  • Review the patient's medical history, including previous biopsy clips, to avoid complications.
  • Explain the procedure, risks (pain, bleeding, infection, implant rupture), and the necessity of a marker clip to the patient.

Needle Types and Usage

We use vacuum-assisted needles with a cutting tip for stereotactic biopsies. Key points include:

  • Understanding the needle's dead space: the target should be at the center of the needle's opening for accurate sampling.
  • Adjusting for errors in x, y, and z coordinates. A five-millimeter error in z is tolerable, but not in x and y.
  • Manually adjusting the needle's depth to ensure proper target placement.

Using the Tomo Guided Machine

The tomo guided machine involves several steps:

  • Place the breast under compression and take tomo images to identify the target area.
  • Use the motorized stage to position the needle based on x, y, and z coordinates.
  • Make manual adjustments to the needle's position for precise targeting.
  • Ensure that the needle is tilted slightly to avoid obstructing the tomo images.
  • Take additional images after initial needle placement to confirm the target location.

Addressing Challenges

To handle specific challenges:

  • If the target is close to the skin, manually move the needle forward so the opening is within the skin, preventing suction of air and skin biopsy.
  • Retargeting after injecting numbing medicine is crucial to maintain accuracy.
  • Use a lateral arm when the breast tissue is not thick enough to fully cover the needle. This involves lifting the breast slightly above the detector for better access.

Technologist's Role

The technologist plays a vital role:

  • They must be thoroughly trained in operating the machine and all related menus.
  • Handling unexpected situations and being familiar with all biopsy options is essential.
  • Only trained technologists should operate the machine for stereotactic biopsies.

Comparing Tomo and Ultrasound-Guided Biopsies

With the advent of tomosynthesis:

  • We see more architectural distortions and asymmetries, making tomo the preferred method for certain cases.
  • The frequency of stereotactic biopsies has increased due to better detection of subtle abnormalities.
  • On average, our center performs five or six ultrasound-guided biopsies and one stereotactic biopsy daily, a significant increase from the past.

Minimizing Patient Movement

To minimize patient movement during the procedure:

  • Ensure the patient is comfortable and in a stable position.
  • Avoid awkward positions by tilting the machine if necessary.
  • Use appropriate-sized paddles for the breast size to ensure proper compression and minimize movement.
  • If the patient moves, retake images, retarget, and adjust the needle position as needed.

Financial Considerations

When considering the financial aspects:

  • An upright machine is more cost-effective as it can be used for multiple purposes (localization, regular mammograms) unlike a prone table which requires a dedicated room.
  • The upright machine allows for better utilization of space and resources, making it a more practical choice for most facilities.

Conclusion

This course covered the key aspects of performing breast biopsies using digital breast tomosynthesis, including preparation, needle usage, addressing challenges, and the technologist's role. The use of tomosynthesis enhances our ability to detect and biopsy subtle abnormalities, making the process more efficient and accurate. I hope these points help you conduct faster and more efficient biopsies. Thank you.