Bone densitometry and breast imaging
As Breast Cancer Awareness month unfolds in October, patients and clinicians alike have cause to celebrate. Recent advances in screening for breast cancer—the leading cancer killer in women—and osteoporosis are increasing the odds of detecting and diagnosing these diseases at earlier stages, when they are most treatable.1
Osteoporosis and bone densitometry
Two in one testing
Some 52 million people in the United States (U.S.) are estimated to suffer from osteoporosis, with 2 million fractures related to the disease occurring each year. Osteoporosis is overwhelmingly a women’s condition, affecting 1 in every 3 women, but only 1 in every 5 men, over age 50.2
Standard operating procedure has been, and still is, for women at risk for the disease to undergo bone densitometry (DXA), a standalone X-ray examination of the wrist, back and/or hip that is then analyzed to measure the degree of bone loss.
But that could soon be changing, thanks to OneScreen, a new screening system developed by Sectra (Linkoping, Sweden). With OneScreen, an x-ray of the hand provides the basis for an osteoporosis diagnosis. In what is essentially a “two in one” exam, the image is taken at the same time as the breast images during a mammogram, and on the same digital radiology equipment. The extra examination takes <30 sec, according to Sectra.
The image is then electronically sent for analysis with Sectra’s patented technology, Digital X-ray Radiogrammetry (DXR). With the help of DXR, women in the osteoporosis risk group can be identified and offered further examination and treatment. Sectra’s online service is ideal for identifying and prioritizing those women who should be referred for the DXA measurement, a more expensive and considerably more time-consuming technique for analyzing bone mass.
According to a Sectra statement issued earlier this year, some 1,000 women in Europe at very high risk of contracting osteoporosis have been identified as a result of the Sectra OneScreen online service.
Introduced at the 2011 meeting of the Radiological Society of North America, OneScreen could soon make its clinical debut in the U.S. Elin Kindberg, Senior Medical Advisor at Sectra, said the company is negotiating with several U.S. mammography providers, and that the service could be operating stateside in the near future.
“We are talking to leading mammography providers in the country and once the service is implemented at one account, we think that many others will follow, considering the simplicity and efficacy of this product, as well as the fact that there is no need for investment in new hardware or software,” Kindberg said.
In the meantime, OneScreen is getting good reviews from European clinicians, such as Dr. Björn Löndalen, a consultant radiologist and chief marketing officer at Unilabs Teleradiology Norway, Unilabs Röntgen Oslo, Norway.
“The OneScreen system provides us with an easy and flexible way of identifying the women at risk [for osteoporosis],” Dr. Londalen said. “As osteoporosis is a ‘silent’ disease, this method allows them to be treated before any fractures occur. The method is rather effective and takes up little time—a complete examination is done in about 30 sec. This allows us to do the exam without having to reschedule, which obviously is a huge benefit in terms of patient compliance.
“The fact that OneScreen is coupled with mammography is also a benefit in the sense that the women coming for a mammogram are already concerned about their health, and doing a check-up on another female-specific area—bone density and osteoporosis—is an easy choice to make when you don’t have to make another appointment. The responses have been almost exclusively positive,” Dr. Londalen added.
With respect to clinicians, Dr. Londalen said, one of OneScreen’s greatest benefits is its ease of use.
“It takes only about 1 or 2 exams for a radiographer to learn the technique,” he said. “There is no need to interpret images. The report sent back by email, or as a DICOM/HL7 in the PACS, gives any clinician or radiologist a full status report at a glance.”
Breast imaging
The medical imaging industry, meanwhile, continues to build its already impressive arsenal of breast screening tools with an array of recent developments in mammography and emerging breast imaging options, such as low-dose mammography and tomosynthesis.
Low dose mammography:
Addressing a growing concern
One of the leading concerns in medical imaging among clinicians and patients is exposure to radiation during imaging exams; and with women 40-years and older receiving an annual mammogram, the call for low-dose mammography is being met by industry leaders.
A study of breast radiation exposure was recently published by the Irish Breast Screening Program. The purpose of the study was to compare radiation dose to the breast per exposure and per exam among the digital mammography systems of 3 leading vendors. The study concluded that Philips Healthcare’s MicroDose low-dose mammography system had the lowest mean glandular dose per image and per exam among the 3 vendors.3
Available in Europe and Canada for several years, the MicroDose full field digital mammography (FFDM) system, which Philips acquired from Sectra, made its debut in the U.S. last April. MicroDose provides all the benefits of existing digital mammography with greater resolution and up to a 40% lower dose than that of competing technology, according to the company.
The MicroDose system is the first to use photon-counting technology, a patented technological revolution in x-ray detector development. The individual x-ray photon is counted by a 50-micrometer detector element, creating very low noise and eliminating analog to digital conversion.2
By using a multi-slit pre-collimator and a matching multi-slit post-collimator, only those x-rays perfectly aligned with the detector are allowed to pass through the breast. All other x-rays are blocked; and scatter radiation, which adds to patient dose and degrades image quality, is minimized.
Raymond Tu, MD, chair of the radiology Department at United Medical Center, Washington, DC, is an early adopter of the system. The MicroDose system was installed at Dr. Tu’s facility in August, providing his facility with the final component needed for accreditation by the American College of Radiology (ACR), according to Dr. Tu.
“I chose Philips because they provided me with a turnkey solution to completely overhaul my existing analog mammography program,” said Dr. Tu, whose facility images an average of 10 breast screening patients per day. “The MicroDose installation was very easy and the engineers were lock step with me to guide our construction team through the process.”
Dr. Tu said the biggest advantage to MicroDose is its low radiation dose. “Patient safety and ‘first do no harm’ are not idle words,” he said. “I want to detect and cure breast cancer. But I don’t want to cause cancer, either. All mammography machines have higher dose than MicroDose. Low dose makes sense.”
Tomosynthesis adds another dimension
Although FFDM is the gold standard for screening for breast cancer, it may not always be the imaging solution for women with dense breast tissue. With conventional 2-dimensional (2D) mammography systems, overlapping breast tissue can hide small cancers or cause normal areas to look suspicious.4 With this in mind, Connecticut pioneered a law in 2009 requiring doctors to provide women with a breast density score after their mammograms.
The introduction of 3-dimensional (3D) mammography, or tomosynthesis, has played a key role in screening women with dense breasts. Hologic’s Selenia Dimensions 3D mammography system is indicated for diagnostic performance, with a one-touch control for seamless, instantaneous transition between imaging modes: FFDM (2D imaging), tomosynthesis (3D imaging), or “combo-mode” imaging (2D+3D imaging). The latter feature quickly acquires a digital mammogram and a tomosynthesis scan in the same compression (a screening exam consists of a digital mammogram and breast tomosynthesis image set).
A study led by Liane Philpotts, MD, Chief of Breast Imaging at the Yale University School of Medicine, New Haven, CT, concluded that adding 3D to a screening exam reduced recall rates by 40%.4
“With Hologic’s 3D technology, we can see the entire breast more clearly in one millimeter slices,” said Dr. Philpotts. “This allows us to find additional cancers earlier and also dismiss ambiguous spots that are actually normal breast tissue.”
Good things come in small packages
Many standalone breast imaging centers are being challenged to upgrade their systems and transition from analog to digital imaging on a limited budget. FUJFILM Medical Systems (Stamford, CT) in March unveiled the Aspire CRm FFDM system as a solution for smaller facilities.
“With the Aspire CRm, Fujifilm women’s health offering continues to expand to provide options to facilities of all sizes,” David Hotchkiss, Director of Modality Solutions Marketing at Fujifilm, explained in a statement announcing the introduction. “Gone are the days of small facilities having to sacrifice image quality or ease-of-use because a digital solution was out of their price range. With the introduction of our Aspire CRm, these facilities can now offer their patients the benefits of digital mammography instead of losing these patients to neighboring facilities who offer this technology. We provide both CR-and DR-based FFDM systems in the U.S.”
The Aspire CRm eliminates film to improve overall workflow while increasing daily productivity and offers optimal image quality and improved dose efficiencies over analog systems. Like the other systems in Fujifilm’s women’s imaging technologies, the Aspire CRm provides radiologists with 50-micron resolution. Additionally, it delivers Fujifilm’s legacy capture technology that improves clarity, contrast, and exposure latitude as compared to screen-film mammography.
References
- American Cancer Society: Cancer Facts and Figures 2012. Atlanta, Ga: American Cancer Society, 2012. Last accessed January 6, 2012.
- Sectra OneScreen promotional brochure. Facts about Osteoporosis.
- Baldelli P, McCullagh J, Phelan, N, Flanagan F. Comprehensive dose survey of breast screening in Ireland. Radiation Protection Dosimetry. 2012;145:52-60.
- Philpotts L, Raghu M, Durand M, Hooley R, Vashi R, Horvath L, Geisel J, Butler R. Yale University School of Medicine. Initial Experience With Digital Breast Tomosynthesis in Screening Mammography. Presented May 3, 2012 at American Roentgen Ray Society Annual Meeting.