1：Experimental Design and Method Selection:

The study involved setting up a low-power optical imaging system (LP-OIS) for fluorescence and bioluminescence imaging. Tumor cells expressing mKate2 or fLuc-GFP were implanted in various body compartments of mice (subcutaneous, abdominal, deep tissue) and monitored over time. Histopathological assays confirmed tumor presence.

2：Sample Selection and Data Sources:

Breast cancer cell lines MDA-MB-435s (expressing mKate2) and MDA-MB-231 (expressing fLuc-GFP) were used. BALB/c nude mice were implanted with these cells.

3：List of Experimental Equipment and Materials:

Equipment included a CCD camera (iKon-M 934, Andor), lens (LM35HC, Kowa), filter wheel (FW102C-EC, Thorlabs), tungsten-halogen lamp (71LT250/71PT250A, Beijing 7-Star), optical fiber bundles (G5.7-2-4000-K, G5.7-4000, Nanjing Chunhui), gas anesthesia system (VIP 3000, Matrx), and various reagents (e.g., DMEM, FBS, PBS from Invitrogen).

4：7-2-4000-K, G7-4000, Nanjing Chunhui), gas anesthesia system (VIP 3000, Matrx), and various reagents (e.g., DMEM, FBS, PBS from Invitrogen). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Cells were transfected and selected with G418. Mice were implanted with tumor cells in different compartments. Imaging was performed using the LP-OIS with specific exposure times (e.g., 1s for mKate2, 30s or 300s for fLuc). Data were processed using Andor SOLIS and ImageJ.

5：Mice were implanted with tumor cells in different compartments. Imaging was performed using the LP-OIS with specific exposure times (e.g., 1s for mKate2, 30s or 300s for fLuc). Data were processed using Andor SOLIS and ImageJ. Data Analysis Methods:

5. Data Analysis Methods: Intensity and area of infected regions were analyzed in real-time. Linear fitting and quantification were done using Origin 8.0. Autofluorescence was accounted for by setting a threshold above 1000 counts.