A laboratory specimen sealed within a chamber on an animal holder may be injected or otherwise administered material such as drugs and radioactive imagining materials from the ambient, or outside the chamber, through a sealed catheter assembly. The animal holder can be mounted on imaging machines such as MRI, X-ray, PET, CT and like imaging machines. Biologically contaminated animals are isolated within the chamber from the ambient, yet may be injected from outside the chamber thereby protecting lab technicians from contamination and isolating the animal from additional contamination from an ambient environment, such as an imaging laboratory.