News Story

Women’s Imaging

Toshiba Focuses on Women’s Health
Mobile Mammo Goes Digital
Adding Ultrasound to IGRT

Toshiba Focuses on Women’s Health

For the past several years, Toshiba America Medical Systems, of Tustin, Calif, has placed a major focus on the women’s health imaging market, and since its debut of several solutions during last year’s meeting of the Radiological Society of North America, the company has been hard at work improving their product portfolio in this specialized niche.

Breast MRI, in particular, is gaining more and more support, as evidenced by the 40% annual increase in reported exam requests.

Coming from a facility with a newly launched breast program, Pamela Otto, MD, director of radiology at University Health Systems and professor at the University of Texas Health Sciences Center in San Antonio, welcomes the continuing development and enhancement of technologies.

Otto, who uses the 1.5T MR system from Toshiba with the Sentinelle coil, said she is happy with the innovation. “It actually provides such superior images than we had before,” said Otto, whose county hospital sees about 30,000 patients a year for imaging. “The resolution is fabulous, so it enables us to see things better than we’ve been able to see in the past.”

Furthermore, patients are also expressing their approval of the Sentinelle coil, a bilateral, dedicated, eight-element coil that is said to provide high temporal and spatial resolution. Otto continued, “The patients are really finding that coil much more comfortable to lie on, and the fact that the coil has a lower profile means that the patient actually then goes on to the middle of the magnet instead of the high side of it, so we can get more patients to fit in the magnet. And then the fact that you can put feet first instead of going head first is a huge benefit to the patient. Nobody likes to go in head first. That way they can keep their head out and feel much more comfortable.”

Next on her agenda, Otto said she and her colleagues are in the process of developing noncontrast MRI of the breast. The group hopes that the technique will mark an improvement for patient comfort and safety, as well as a way to decrease cost.

Toshiba’s exclusive MicroPure microcalcification detection technology also addresses cost savings, as well as benefits in time management and the emotional aspect of the imaging process. Cassie Murvay, Toshiba product manager for ultrasound, explained that the solution has the potential to reduce the number of stereotactic biopsies, but additionally, “It’s easier on the patient, there’s a cost savings, and they can usually do an ultrasound immediately, whereas stereotactic requires scheduling, so a lot of times the patient has to come back. If there is concern that there could be a potential of cancer, we’d like to give that patient an answer as soon as possible, instead of days or weeks.”

When Toshiba started the development process in 2006, its biggest goal was being able to detect the microcalcification. Since then, the company has looked more at the characterization of the calcification, according to Erin Owen, Toshiba senior product manager for ultrasound. “We’ve been able to readjust the adaptive filter to be able to see deeper tissue in a more consistent pattern now.”

Customers can expect to see improvements in this area when the next software edition is released, Owen said.

Adding Ultrasound to IGRT

Within 18 years of initial diagnosis, nearly a quarter of breast cancer survivors experience a recurrence in the breast that had been treated with breast conservation therapy, the combination of lumpectomy (surgical removal of the tumor) followed by radiation therapy, according to figures from the National Cancer Institute. Other research shows that at least 90% of these recurrences occur within one centimeter of the tumor cavity.

The Clarity Breast System allows for daily monitoring of the lumpectomy site based on visualization of the actual anatomy rather than estimation of its location.

According to Tony Falco, chief executive officer of Resonant Medical, of Montreal, daily movement of the lumpectomy cavity, the area where the tumor was removed through surgery, in large part, explains the statistics. The disease is most likely to return near the original, primary sites, suggesting that a section of the breast did not receive the full dose of radiation during treatment, Falco continued.

“We know today through our trials that the lumpectomy cavity can move from day to day,” he said. “We find that it could move as much as 3 cm, and if you have radiation margins of 2 to 3 cm, then some of the time you’ll be off target. Even if one cancer cell survives the treatment, it can come back quickly. You’ll have a recurrence that is much tougher to treat the second time around.”

To address the need for accurate, precise delivery of radiation therapy, Resonant Medical has developed a technique that combines traditionally used CT data with an ultrasound product from a Canadian manufacturer during planning and treatment. Called the Clarity Breast System, the approach enables radiation therapists to image the lumpectomy cavity at the planning stage and then daily with each consecutive radiation treatment. As a result, clinicians can obtain a visual image and exact location of the lumpectomy cavity on a regular basis, without exposing patients to additional radiation.

Beginnings of Radiotherapy

When radiotherapy first emerged several decades ago, physicians did not have a way to take internal images of the patient, Falco recalled. As a result, doctors did not know how things were moving around inside the body. The idea, then, was to use large radiation fields in order to ensure that the cancerous area was included. “Typically for breast cancer, you’d include a large portion of the lung and heart, as well as the breast,” Falco said. “This meant that the level of radiation that could be given was basically determined for a threshold percent on the amount of radiation to be delivered because of what the healthy tissue surrounding the diseased organ can actually take.”

With large fields and a low amount of radiation, many patients did not survive the treatment and did not receive enough radiation to destroy the cancerous cells. Nevertheless, a decade later, conformal therapy arrived on the scene. This new method of treatment debuted with quick acceptance from the medical community, who marveled at its promising capabilities.

“Once you reduce the size of your radiation fields and include less healthy tissue, then you start to increase the prescription dose, so the number of patients who survived increased as well,” Falco said. “It’s really a geometric-type argument that you make in radiotherapy, where you reduce the fields, have smaller margins around the diseased area, and include less healthy tissue that allows you to increase the dose.”

During the time that conformal therapy began gaining popularity, Falco applied his doctorate in medical physics at a clinic in Montreal-based McGill University. Noting that the push for the emerging technique resided in the fact that it allowed more patients to be cancer free, Falco thought about the procedure’s shortfalls. Particularly, he saw that the x-ray-based imaging that clinicians used to target the cancer site was not ideal.

“The problem with x-ray imaging is that it’s really most suited for looking at bone anatomy or lung, sort of the extremes. It’s not very good at looking at soft tissue and the distinctions between soft tissue,” he continued, adding that in an x-ray image, soft tissues, such as a lumpectomy cavity or prostate, appear washed out.

In addition to its price point, an MRI would need to be housed elsewhere in the hospital. Scheduling would also be an issue, Falco noted. The best type of imaging for targeting soft tissue was ultrasound, he realized. The dedicated equipment could be placed conveniently within the department.

An Idea Is Born

Cleared by the FDA in 2004 for guidance during external beam radiation treatment, including prostate and breast treatment, the Clarity System allows for daily monitoring of the lumpectomy site based on visualization of the actual anatomy rather than estimation of its location. Three-dimensional ultrasound data is combined with CT data, providing users with twice the amount of information used traditionally.

“At the planning stage, we developed a 3D ultrasound application that would give the physician much more information than they have today to be able to plan the treatment, locate the cancer areas, see the healthy areas, and simulate the kind of radiation beam angle they would have to use,” Falco said.

During the treatment stage, the technology requires a mere 60 seconds before finding the cancer and letting the therapist know how much the tumor has shifted from day to day.

In studies performed at several centers in the United States and Canada, Resonant was able to demonstrate that if patients were imaged using CT alone during a particular type of breast treatment known as electron boost, physicians may be missing or overestimating the diseased area in about half of the treatments.

Ruth Heimann, MD, of Fletcher-Allen Healthcare, Burlington, Vt, is in the midst of running one such trial for partial breast radiation and is currently analyzing data from a previous trial. She stumbled upon Clarity a few years back during a meeting of the American Society for Therapeutic Radiology and Oncology and was drawn to the idea of merging CT and ultrasound images to produce a 3D image without adding radiation.

In her completed trial, Heimann and her team examined how Clarity could be useful in the boost phase of breast radiation, specifically monitoring changes in the lumpectomy cavity in 20 patients. Although she is still in the process of analyzing the data, which she collected over a span of a year and a half, Heimann already notices one trend. “We are seeing that the cavity moves with time and changes, so it is important to localize on a regular basis.”

Following the Times

In total, Resonant has 60 Clarity customers, with 32 centers using the technology in the United States. About half of the centers are research centers, with the remaining 50% split between community centers and freestanding clinics. About 500 patients a day are treated with the system.

Short-term goals consist of studying feedback from the company’s work with centers, with a specific focus of improving the breast products.

Looking ahead even further, Resonant will be investigating opportunities in radio-frequency ultrasound imaging, which would allow physicians to look more closely at the body’s cellular level. “We’ll try to see if we can pick up areas where not enough radiation has been given,” Falco said. “If we’re able to look at the very small level and see the kind of damage the radiation gives, we might be able to pick out which patients would most likely have recurrences going forward. If we can, for those patients, we could boost the amount of radiation that we’re giving them.”

By examining disease at the tissue level, Resonant hopes to figure out a predetermination as to which patients would fall into the recurrence category. In doing so, physicians could treat cancer now rather than in 10 to 20 years, when the disease becomes more difficult to treat.

“We’re developing the technology to follow the times,” Falco said.