Research and Development at University of Michigan
The University of Michigan (U-M) conducts a broad variety of research, from studying health outcomes to research that is designed to improve the quality of implants. The broader research enterprise of the university’s medical school is overseen, in part, by the Associate Dean for Research, Karl Jepsen, PhD. He is also Professor for Orthopaedic Surgery at U-M, hence one focus area of his lab is better understanding how the skeletal system establishes function during growth and maintains function throughout the aging process to prevent bone fragility: from osteoporosis to scoliosis, pediatric fragility, and stress fractures. In addition to the in-house research, Dr. Jepsen also offers his lab’s facilities, equipment and expertise as a service to the broader research community. Cooperation partners include other medical and research institutes like Harvard, Yale, and Ohio State University, but also the US Department of Defense.
Almost all of this research (95%) is done ex-vivo, allowing the use of microCT and nanoCT technology at higher kilovoltages for the highest possible resolution. Moving beyond the traditional use of CT technology to scan bones and other mineralized tissue, current research efforts also utilize CT to study soft tissues and blood vessels for which higher detail detectability in regions of interest as small as 5 microns and below is necessary. This overall very broad range of U-M’s research thus requires flexible analysis equipment and methods that can quickly accommodate the different challenges and needs of the lab’s own as well as contracted work.
In short, the three main challenges the university’s research CT lab is facing, are:
- High volumes of samples that need to be scanned within short time periods
- Diverse analysis requirements that need to be covered by the same equipment
- Complex samples that require high detail detectability to gain the needed insights
To address these challenges, Karl Jepsen has been deploying CT systems from Waygate Technologies in his lab for a long time.
“We need to keep up with state-of-the-art equipment so we can push the boundaries on discovery research and compete for federal funding, which is how we largely support our enterprise. To do that, a CT system that combines the ability to service large sample volumes with high detail detection and a wide range of penetration power from nanofocus to microfocus CT to match any given task with great flexibility, is crucial to us. We found that in the Phoenix CT systems from Waygate Technologies.”
To acquire highest resolution images fast and outcompete other research groups, Karl Jepsen’s team has deployed a Phoenix Nanotom S as well as a Nanotom M. The Phoenix Nanotom S, launched in 2005, was the first nanoCT® research system. More importantly, the nanoCT® technology of the Phoenix product line opens up new areas of exploration. Beyond bone and implants, the field is moving to examining soft, non-mineral tissue like vascular or heart tissue. With regular microCT for higher absorbing samples such as larger bones, imaging can however not go below 6 microns, not sufficient for investigators who want to have the flexibility also to scan small low absorbing samples with highest detail detectability so they can quantify small structures within them. The Phoenix Nanotom M was further optimized with a view to higher flexibility for a larger sample and application range and much better spatial and contrast resolution. The 180 kV / 20 W X-ray tube deployed in both systems offers several operation modes, from nanoCT to high power microCT.
The excellent detail detectability of up to 200 nanometers of Waygate Technologies’ nanoCT systems is valuable in more traditional research and samples, as well. In the pediatric research U-M conducts on bone growth, for example, state of the art microCT scans of small post-natal mouse bone did not provide quantifiable images. The Phoenix Nanotom M however allowed researchers to quantify bone from birth on.
Karl Jepsen finds multiple benefits for the nanofocus X-ray tubes: “The difference in quality is night and day between a microCT system and the Nanotom, even if you look at the same resolution image. That’s where other investigators in the field need additional education on the value of this technology. Even at a lower resolution you have a much-improved feature detection.”
In his study of osteoporosis, looking at porosity as a function of age is central. To get the necessary insights on this aspect, the lab needs to look at human proximal femurs in one image. With Waygate Technologies’ Nanotom or V|tome|x, a whole human femur cross section can be imaged at 5-10 microns. The high-resolution quality of those images provides new insights and allows the researchers to start asking new follow-up questions, enabling progress in their research and allowing them to procure new grants.
Similarly, the lab’s research on scoliosis looks at explant rods that were implanted in children and youths for 3-4 years for stabilization. Because the rods are subjected to the growing bone structure of the kids, there is concern about debris accumulation. With the explants, it is thus crucial to study them non-invasively to guarantee any detected debris was not caused by opening the implant. High-resolution CT, for best imaging quality the nanoCT technology, makes this possible.
Superior detector and imaging technology can also address another of U-M’s challenges: Volume. Scans of an entire femur cross section e.g. typically take four to eight hours. With the Phoenix V|tome|x M for example, the lab could bring scanning time down to no more than one or two hours. With soft tissue, time is of the essence because scanning time is usually even longer and it is a challenge to keep a fixture stable for up to 46 hour scanning periods so as not to lose resolution because of vibration or thermal movements. In cases like these, where slight motion blurs cannot be avoided, high power and resolution as well as high dynamic detectors become key.
Especially with a view to the contract business, servicing high volumes translates into direct money. Enhanced volume capacity allows the lab to offer more bulk services to outside researchers and generate more income. Demand for the “plug-and-chug service” is high. “People come in with 200 bones and want them scanned by tomorrow”, says Jepsen. Getting the required quality at fast speeds is the “holy grail of research” as Jepsen calls it. The desired solution for the U-M lab is a Phoenix V|tome|x M from Waygate Technologies, which includes two X-ray tubes that can be changed just by pressing a button: For highest resolution scans a 180 kV / 20 W nanofocus tube like in the Nanotom, for high power microCT scans of larger or high absorbing samples a 300 kV / 500 W microfocus X-ray tube: “With that dual-tube combination, we can do both, microCT, which is more than adequate for explants and then we can switch over to the nanofocus tube for vascular studies, because these require going down to 5 microns.