Key Differences Between 3D Tomosynthesis and micro-CT

In breast-conserving surgery (BCS), specimen imaging plays a key role in helping to confirm clear surgical margins.  2D X-ray was the initial mode of intraoperative specimen imaging, but 3D X-ray imaging offers significant advantages by viewing the specimen in three axes. This can help the surgeon to better balance tumor removal with breast tissue preservation and procedural efficiency. Two 3D X-ray imaging methods — Tomosynthesis and Micro-Computed Tomography (micro-CT) —provide distinct approaches for evaluating breast tissue specimens during surgery. Understanding the differences between these technologies can help healthcare providers select the best option based on specific clinical and operational needs.

What is 3D Tomosynthesis?

Tomosynthesis provides high-resolution, 3D imaging by capturing multiple X-ray projections at various angles around the specimen. This technique generates an image that can be examined in slices, allowing surgeons to visualize the depth and extent of lesions with precision. Its high contrast resolution and ability to visualize both dense and soft tissues make it ideal for breast tissue imaging, including the visualization of microcalcifications and tumor spiculations. Given these advantages for imaging breast tissue, it is no surprise that Tomosynthesis has become the standard in 3D diagnostic mammography, with demonstrated improvements in lesion visualization and diagnostic accuracy. This makes it a familiar and reliable choice for radiologists and surgeons alike when it comes to specimen imaging.

KUBTEC holds multiple patents for the use of Tomosynthesis in intraoperative specimen imaging cabinets. Their Tomosynthesis system, The MOZART System, has been shown to reduce re-excision rates significantly compared to 2D systems. Tomosynthesis also enables rapid image acquisition, and the images are relatively straightforward to interpret, providing quick feedback that allows surgeons to make real-time adjustments without lengthy processing times or radiologist input.

Understanding micro-CT Imaging

Micro-CT is another form of 3D imaging that rotates the specimen on a turntable while keeping the X-ray source and detector stationary. This technique provides good spatial resolution and is commonly used in research and hard tissue analysis, such as bone imaging. However, it has lower contrast resolution for soft tissues, making it less effective for distinguishing the fine details needed for accurate soft-tissue visualization, like subtle contrasts in breast lesions. This is one of the reasons the technology has not been widely adopted for breast tissue imaging, including diagnostic mammography.

Micro-CT also requires more processing time than Tomosynthesis for image acquisition and reconstruction, and the larger the specimen the longer the time. Intraoperatively, this extended imaging time may disrupt workflow and increase the time a patient spends under anesthesia. Micro-CT images also typically require radiologist interpretation, adding complexity to real-time decision-making. These factors compound the reasons why micro-CT has failed to be widely adopted for specimen imaging, including significant attempts by Hologic / Faxitron (FDA approval in 2018¹, product end-of-sales / life in 2022²) among others.

Enhancing Outcomes with Advanced Imaging Techniques

For intraoperative breast specimen analysis, Tomosynthesis can be considered better suited than micro-CT due to its quick image acquisition, high contrast resolution, and ability to visualize both dense and soft tissues. While micro-CT is valuable for research and precise anatomical imaging, Tomosynthesis offers the speed and clarity necessary for effective, immediate intraoperative margin assessment. For facilities aiming to enhance workflow efficiency and improve clinical outcomes, Tomosynthesis offers a balanced approach well-suited to the demands of breast conservation surgery.

For more detail and reference papers, please see:‍

Fundamentals of Specimen Tomography, Comparing the Performance of Intraoperative X-ray Imaging for Breast Conservation Surgery, Trevor L. Vent and Andrew D. A. Maidment

Additional references:
1. FDA Letter, 2018. Re: K173309, Faxitron VisionCT
2. Faxitron® CT Specimen Radiography System End-of-Sale (EOS) / End-of Life (EOL) Notification, October 2022

‍