Detector Group builds imaging device for German Research Center

While nearly every member of the Detector Group played a role in developing or fabricating the device, Mark Smith, project manager for this effort, and Detector Group members Vladimir Popov and Ben Welch went to the DKFZ during the week of April 24 to assemble, bring on-line and calibrate their mini-gamma camera imager for small animals. Popov's primary responsibility was the camera's electronics, while Welch worked on data acquisition and the user interface.

"Joerg Peter, leader of the DKFZ Functional and Molecular Emission Computed Tomography Group, was pleased that the first quality control images were taken within a day of our arrival and that the first animal images were obtained by the end of the week," Smith said after his return to JLab.

Nuclear Medical Image of a Mouse. Mouse images were obtained after injection of Tc-99m MDP -- technetium- 99m methylene diphosphonate -- a bone-imaging radiopharmaceutical.

"In December we shipped the larger components and the electronics rack; and during the April trip we hand-carried the delicate electronics," Smith explained.

"We're very excited about getting the system operational," he continued. "The imager will be used for research projects to gain physiological information on animal models of human disease. The detector head was successfully integrated with the previously shipped components of the imaging system and with a pinhole collimator developed by the DKFZ. Calibration and quality control tests were successfully performed; and Ben Welch provided a thorough introduction on the use of the imaging system to DKFZ researchers during these tests." Mastering the machine's capabilities and the calibration process are critical to the cancer researchers' work as they will be using more than a dozen different radiopharmaceuticals in their research.

Jefferson Lab's work on the project began in June 2004. The Lab received approximately $86,000 from the DKFZ to build the gamma camera under a Work for Others Agreement. "This type of high-resolution device isn't available commercially and the German research center didn't have the capability to fabricate its own," Smith explained. The basic device is along the same line as other small animal imaging gamma cameras developed by the Detector Group.

However, group members are constantly refining their work. This imager design is based on a new concept developed by Vladimir Popov (idea has been submitted for a patent) which resulted in highly improved detector performance. "This device has notable improvements, and we built it with a new type of flat panel position-sensitive photomultiplier tube," Smith said.

Members of the Detector Group Using Imager. Mark Smith, Joerg Peter, DKFZ, Vladimir Popov and Ben Welch (left to right) observe a mouse bone study at the German Cancer Research Center being performed with the new small-animal imager built by JLab’s Detector Group.

The effort to develop international collaborations such as this one began a few years ago when Detector Group Leader Stan Majewski requested that Mark Smith seek out potential scientific partners in Europe, to provide additional, crucial evaluations of JLabdesigned imagers by implementing them in real biomedical projects.

Smith traveled to Europe and after visiting several places in the Netherlands and Germany, returned with the DKFZ collaboration plan. Smith's long-time friendship with a senior DKFZ scientist, Joerg Peter, was a plus in developing the working relationship. The two researchers have known each other since their years at Duke University Medical Center. "We stayed in touch over the years. Ideas grew up during our conversations during professional conferences, based on our mutual interests," Smith said. "He knew the sorts of things we could build here, so when they needed a small-animal imager, we were a good fit to build it for them."

The DKFZ research institute has integrated the gamma camera with a non-JLab optical camera that images bioluminescence and fluorescence markers for dual modality small-animal imaging, which will make it easier to correlate the information provided by the different imaging modes.

"Also during the visit, we jointly prepared an abstract titled 'Development and Initial Results of a Dual-Modality SPECT/Optical Small Animal Imager', for the 2005 IEEE Medical Imaging Conference," Smith said. The Detector Group primarily assists with the design and construction of apparatus for the highly complex detection systems that gather data on subatomic particles in nuclear physics experiments conducted at JLab. The group has also used its core detector instrumentation expertise to develop a variety of clinical and biomedical research imaging devices. Other members of the group who participated in this project are Randy Wojcik, Brian Kross and Stan Majewski.