1. Why switch from SCO (Secondary Capture Object) to BTO (Breast Tomosynthesis Object)?
BTO is now the DICOM standard, which allows for greater flexibility in sharing and storing images.
2. How does breast tomosynthesis aid in resolving tissue superimposition?
When viewed as a 2D, flat image, different structures located at different heights within the breast may overlap and cause confusion for the reviewer. Overlapping, or superimposed tissue is a leading reason why small breast cancers may be missed and normal tissue may appear abnormal, leading to unnecessary recalls.
Breast tomosynthesis deconstructs and separates breast tissue into thin cross sectional slices, so that the radiologist can see clearly what lies within the breast, free from the confusion of superimposed tissues. The ability to review breast tissue in high resolution, one millimetre slices provides radiologists the added confidence,1 to significantly reduce recall rates4. It has also been shown to find cancers missed with 2D mammography.3
3. Tomosynthesis dose – is it higher than digital mammography?
Tomosynthesis dose is higher than a standard digital mammography exam; however, the total dose in a combo-mode exam (digital mammography + breast tomosynthesis) is well within the allowable MQSA and EUREF standards. Members of the FDA advisory panel reviewing the technology agreed that the benefit of this technology outweighs any perceived risk from radiation.1 Furthermore, the use of tomosynthesis in diagnostic assessment offers the opportunity for both improved performance and a reduction in the number of x-ray images needed, with a resultant reduction in both dose and exam time. 2,6
4. I’ve heard that with breast tomosynthesis, it is hard to identify microcalcifications – is this true?
The Selenia Dimensions system is optimised with a short, 4 second breast tomosynthesis scan time to reduce the possibility of motion blur, resulting in calcifications that are easily seen.7
5. Is there a reduction in recall rates associated with performing combo-mode (digital mammography + breast tomosynthesis)?
Multi-centre, multi-reader clinical studies included in Hologic’s FDA submission proved a statistically significant reduction in recall rates.1 In addition, a recently prospective screening study also indicates a statistically significant reduction in recall of 40%.8,12
6. What is the potential increase in cancer detection from using tomosynthesis in a screening environment?
A recently published large scale study, “Implementation of Breast Tomosynthesis in a Routine Screening Practice: An Observational Study,” led by Dr. Stephen L. Rose, supports the use of Hologic's breast tomosynthesis in cancer screening, by demonstrating a significant reduction in recall rates along with a sizeable increase in cancer detection, particularly invasive cancer. These findings are consistent with and supplementary to previously published studies including the Oslo Tomosynthesis Screening Trial (published in Radiology) and the Screening Tomosynthesis or Mammography (STORM) trial in Italy (published in The Lancet Oncology).
7. Why should I buy tomosynthesis today when the technology is new and other vendors are coming out with systems?
The Selenia Dimensions platform was built from the ground up specifically for advanced applications. Hologic’s breast tomosynthesis system has been commercially available since 2008 in global markets and is optimized for screening, diagnostic, and interventional performance. It is currently the only FDA approved breast tomosynthesis system in the U.S.4
8. I have been told that tomosynthesis only benefits women with dense breast tissue. Is this true?
Digital mammography plus breast tomosynthesis (combo-mode) has been shown to improve the performance of mammographers in both fatty and dense breast types; and combo-mode is superior to digital mammography alone for all women regardless of breast tissue type.1,6 The Hologic tomosynthesis screening exam offers an increase in cancer detection3 and a reduction in recall rates8 compared to 2D mammography alone.1 Dr. Rafferty studied the performance of breast tomosynthesis in women with dense breasts and found an increase in the recall for cancer cases and a reduction in the recall rate for non-cancer cases.5 In a separate study, Dr. Rafferty found that combo-mode was significantly better than digital mammography alone in ROC performance for both fatty and dense breasts.6,5
9. I have heard that tomosynthesis will reduce the use of ultrasound and MRI. Is this true?
While all women can benefit from a tomosynthesis screening exam, dense breasted women have been shown to benefit more.1,6 Tomosynthesis may be considered as an alternative to ultrasound as it can be done at the same time rather than having the patient return on a separate visit. Tomosynthesis virtually eliminates the confusion of overlapping breast tissue. Studies show that tomosynthesis finds more cancers earlier and has less false positives than breast ultrasound.7
10. Does tomosynthesis eliminate false positives? Will patients go directly to surgery?
Breast tomosynthesis deconstructs and separates breast tissue into thin cross-sectional slices, so you can see clearly what lies within the breast with high resolution on each slice for added confidence.1 The system is not intended to be used as a replacement for biopsy procedures; and studies show that although tomosynthesis reduces callbacks due to false positives, patients will still have their biopsy prior to surgery.3
1 FDA PMA submission P080003. 2 Zuley M, Sumkin J, Ganott M, et. al. Digital breast tomosynthesis vs. supplemental diagnostic mammography images for the evaluation of non-calcified breast lesions. Radiological Society of North America annual meeting. Chicago, Il, 2011. 3 Skaane P, Gullien R, Eben EB, et. al. Reading time of FFDM and tomosynthesis in a population-based screening program. Radiological Society of North America annual meeting. Chicago, Il, 2011. 4 Bernardi D, Ciatto S, Pellegrini M, et. al. Prospective study of breast tomosynthesis as a triage to assessment in screening. Breast Cancer Res Treat. 2012 Jan 22 [Epub ahead of print]. 5 Rafferty EA, Niklason L. FFDM versus FFDM with tomosynthesis for women with radiologically dense breasts: an enriched retrospective reader study. Radiological Society of North America annual meeting. Chicago, Il, 2011 6 Rafferty EA, Niklason L, Smith A. Comparison of FFDM with breast tomosynthesis to FFDM alone: performance in fatty and dense breasts. Tomosynthesis Imaging Symposium, Duke University, 2009. 7ICPME. 2012. http://courses.icpme.us/class_learn?course=221 March 22, 2012. 7 The American College of Radiology Imaging Network (ACRIN) 6666 study 8 Philpotts L, Raghu M, Durand M, et al. Initial Experience With Digital Breast Tomosynthesis in Screening Mammography. Presented at the ARRS 2012, Scientific Session 22 - Breast Imaging: Screening/Emerging Technologies.