## 4 A Case Study  
To demonstrate the effectiveness of CageView in conducting experiments, here we considered a common procedure that required fasting and monitoring of mice. This information was taken from a real-life experiment conducted in the Small Animal and Materials Imaging Core Facility at the University of Manitoba. Positron emission tomography (PET) imaging is a 3D imaging modality requiring the injection of experimental animals with a radioactive tracer. The most common tracer used in PET imaging is fluorodeoxyglucose (FDG) labeled with 18F-FDG. This tracer is taken up by cells in the same way as glucose is taken up. However, once inside cells, 18F-FDG cannot enter the normal metabolic pathways that glucose enters and cannot be transported out of cells. This leads to an accumulation of 18F-FDG that is dependent upon the metabolic activity, making it a useful marker of tumor activity. Prior to a PET scan, a period of fasting is required to reduce blood glucose levels. This reduces competition between endogenous glucose and 18F-FDG for transport into cells, improving 18F-FDG uptake and thus improving the signal in PET scans. For experimental rodents, this period of fasting is typically 8-10 h. As 18F-FDG has a very short half-life (110 min), it is not feasible to start PET experiments late in the day, as the quantity of activity required to ensure an adequate supply after many hours of decay would be prohibitive. This means that PET imaging is usually started as early as possible in the morning, necessitating that animal fasting commences in the early hours of the morning. Currently, this fasting is achieved by manually removing food from the cage. Because mice are typically scanned singly and sequentially, food removal must also be performed singly and sequentially. The time between food removals is dictated by the duration of the PET scan. This can entail a worker removing food at 12:00 a.m., 1:00 a.m., 2:00 a.m., 3:00 a.m., and so on. A typical experimental workflow is shown in Table 1, assuming the imaging 6 mice and that 18F-FDG is available at 9:30 a.m. Assuming 18F-FDG was available at 9:30 a.m., the first mouse can be injected at 10:00 a.m. A 10-h fasting period requires the food to be removed from this mouse at midnight. The animal is then placed on a warming pad at 9:00 a.m. (warming reduces 18F-FDG uptake in brown adipose tissues, which reduces tumor uptake and produces hot spots on images related to brown adipose tissue) for 1 h. After the warming period, the animal is injected with 18F-FDG, returned to the warm cage for 30 min, and then imaged for 15-30 min. Following imaging, the animal is returned to the designated holding room (a holding room covered by an institutional radiation safety permit), where it must remain for 10 half-lives before it can be returned to normal housing. In the case of 18F-FDG, this in effect requires a 24-h period in the holding room. As these experiments are time-sensitive, a 30-min window is typically scheduled between scans to accommodate any unexpected problems during imaging. This means that unexpected delays in one scan do not impact the next scheduled scan. Following this schedule, fasting is initiated at midnight and then every hour until 5:00 a.m. Manually removing food according to this schedule is clearly problematic, and CageView controls food access without manual intervention. A further advantage of CageView in such PET experiments is the ability to remotely monitor the activity of a mouse. All animals must be monitored by qualified staff at