Population: A total of 70 patients (89.7%) were analyzed, while 8 were excluded as their imaging was performed using different equipment and protocols. All patients participated in DL1, while DL2 (FDG PET/CT staging) involved 29/70 (41.4%) patients, and DL3 (staging with BS and CT-CAP) involved 41/70 (58.6%). As data on consumption and administration of contrast medium and radiopharmaceuticals were not available, it was decided to exclude these patients from the analysis.

Scan Time: The overall scan time varied significantly between diagnostic lines. DL2 had the shortest mean scan time (0.27±0.04 hours), followed by DL1 (0.37±0.05 hours), and DL3 (0.56±0.04 hours). Within DL3, BS required 0.35±0.01 hours, while CT-CAP required 0.21±0.03 hours (p<0.05).[fig1]

Energy Consumption and Greenhouse Gas (GHG) Emissions: DL2 was the most energy-efficient, consuming 4.92±0.81 kWh/patient, compared to 11.10±1.72 kWh/patient for DL1 and 12.05±1.65 kWh/patient for DL3. DL2 showed a 55% reduction in energy use and GHG emissions compared to DL1 (1443.03 vs. 3255.63 KgCO2e, p<0.05). DL1 consumed 7% less energy and emitted 7% less GHG than DL3. Within DL2, BS consumed 3.11±0.14 kWh/patient (912.16 KgCO2e), while CT-CAP consumed 8.93±1.60 kWh/patient (2619.16 KgCO2e).[fig2],[table5]

Contrast Agent and Radiation Dose: Radiation dose for FDG PET/CT included an average CT scan dose of 326.66±45.08 mGy/cm and 241.71±42.00 MBq of 18F-Fluorodeoxyglucose. For BS, radiopharmaceutical injections averaged 693.87±67.32 MBq. CT-CAP reported doses of 2152.89±340.62 mGy/cm and an average iodine contrast media volume of 114.72±22.00 ml. DL1 (WB-MRI) required no ionizing radiation or contrast agents. The combined radiopharmaceutical dose for DL2 and DL3 was approximately 936 MBq/patient, while CT scans contributed a cumulative dose of around 2480 mGy/cm. [table6]