"Deciding where to place the imaging equipment—either inside or outside the animal barrier—proved to be a real challenge because there are considerable advantages and disadvantages to both scenarios," says P. Timothy Lawson, D.V.M., campus veterinarian and director of the Division of Lab Animal Medicine at UCLA.

Test animals must be removed from their vivariums in order to be scanned. Since many of the subjects are being used for cancer research, their immune systems are severely compromised. Removing them from the controlled environment of the vivarium radically increases their chances of becoming infected. Placing imaging equipment inside the barrier makes it easier to conduct experiments without disrupting the test subjects, but it limits accessibility and requires investigators to work in gloves, masks, and gowns.

Because of the size, weight, and sensitivity of many of the imaging tools, floor space and access are also a constant challenge for designers.

"With PET imaging, isotopes have to be made in close proximity to the scanner because they degrade very quickly, sometimes in a matter of minutes. So you need to have a cyclotron close to where you are doing your PET scan, which increases demand on the space," says Dr. Lawson.

After extensive consideration, CNSI planners opted to place the new imaging suite directly adjacent to a modified small-animal containment room.

Designed for Collaboration

Designed by New York-based Rafael Viñoly Architects, CNSI will contain wet and dry research labs and support facilities for cross-disciplinary research in chemistry, biology, physics, and engineering, as well as advanced fabrication and high-tech imaging tools. The imaging suite will be situated adjacent to the animal barrier and contain a comprehensive array of modern tools, including PET, CT, and CCD scanners. When completed in 2005, the CNSI will house more than 220 researchers, faculty, and support staff.

The imaging suite will make extensive use of modern imaging technology such as Positron Emission Tomography (PET). With PET technology, a radioactive isotope called a "tracer" is coupled to a chemical, such as glucose, and injected into the test subject. The PET scanner measures the metabolism of the isotope, creating images that are highly useful for brain and cancer research. One of the primary functions of CNSI's small-animal imaging suite will be to develop new chemical tracers that can be used for tracking cell function in the liver, spine, and cancerous tumors.

To accommodate the greater needs of the UCLA research community, and minimize the risk of corrupting small-animal experiments, the CNSI imaging suite will be situated adjacent to a 920 cage-capacity vivarium with a modified design that allows researchers to safely pass mice back and forth.

"Even though the mice are imaged outside of their micro-environment, we want to do our best to return them to barrier conditions," says Dr. Lawson.

Researchers enter the vivarium room through an air-locked safety corridor. Animals are checked out individually and passed out of the room through a bio-safety cabinet using an innovative design similar to a bank drive-up window. Because they are often radioactive after imaging, they are placed in a separate "cooling off" chamber for at least 24 hours before being placed into a sterile container and passed back into the barrier room, again through a safety cabinet. The suite also has an auxiliary cabinet-style cage washer and autoclave. Dirty cages are processed and returned directly in a controlled environment.

New Challenges and Modern Solutions

Though the compromise struck by CNSI planners is a progressive response to a complicated set of challenges, it remains to be seen if the system will work as planned. Other universities and institutions have responded differently to the same challenges. The opposite approach was taken at Johns Hopkins University where the imaging suite is situated inside a small-animal containment facility.

"Anyone working in this field must confront these issues, and there aren't always clear answers," says Bob Adams, D.V.M., Animal Resources clinical director at Johns Hopkins University.

Dr. Adams emphasizes the importance of spending time to determine the best option based on the needs of the particular institution.

"The design issues surrounding these facilities are complex and the cost of the imaging equipment is significant. It's important to spend the time and money to determine what location is going to be best for the institution at large," says Dr. Adams.

University of California, San Francisco (UCSF) is also in the process of building a small-animal imaging suite. Similar to the CNSI design, the imaging facility will be located outside of the small-animal barrier, but mice will not be returned to the barrier after being scanned. Instead, they will be transferred permanently to a separate facility.

"We crafted a compromise that hopefully will protect our animals and make the facility useful for a greater variety of research," says Clifford Roberts, D.V.M., director of UCSF's animal care facility.

To manage this approach, only certifiably "clean" animals are allowed into the imaging suite to prevent seeding the equipment with pathogens or parasites. Once mice from the barrier are imaged they are taken to a sort of "halfway-house" where they will be handled with extra care in micro-isolator cages opened only in a safety hood.

Lessons for the Future

There are very few design precedents for these types of facilities, but UCLA and other organizations are learning important lessons as they integrate imaging technologies with modern research techniques. Among these is the importance of advanced planning.

"These machines have extremely high power demands and generate a considerable amount of heat, requiring equally significant ventilation. It's very important to know the manufacturer's specifications before you start planning a laboratory around them," says Dr. Lawson.

Researcher access is another big issue. Dr. Lawson emphasizes the importance of considering traffic-flow, type of research, and radioactive containment procedures.

"If you're going to build a modern imaging suite, it needs to be adjacent to a vivarium because the test animals are either bio-hazardous or radioactive when they come out and you can't take them through public areas. So, it's important to consider the traffic-flow of both animals and people," says Dr. Lawson.

Regardless of the logistical complexities, it's clear that the integration of imaging technology with other types of research will be a growing issue for facility planners.

"I seldom read a research protocol now without some imaging component. Our current UCLA imaging suite is a very high traffic facility, averaging some 270 experiments a week," says Dr. Lawson

"As organizations continue to build imaging suites these issues will become easier to solve. Technologies will become smaller and we'll see more imaging tools inside containment barriers, but research universities are always pushing the edge of technology so it is probably never really going to be cheap," says UCSF's Dr. Roberts.

By Johnathon Allen