How to dispose of Technetium-99m (Tc99m) and Fluorine-18 Fluorodeoxyglucose (F18 FDG)?

Disposal of Tc-99m and F-18 FDG Radioactive Materials

Radioactive waste from Tc-99m and F-18 FDG should be stored for 10 half-lives (60 hours for Tc-99m and 18 hours for F-18) before disposal, after which the material should be surveyed to confirm activity is below exemption levels. 1

General Principles for Radioactive Waste Disposal

• Radioactive waste from nuclear medicine procedures requires special handling based on the radionuclide's half-life and emission characteristics 1
• Tc-99m has a half-life of 6.01 hours with gamma emissions and an exemption level of 0.354 MBq 1
• F-18 has a shorter half-life of 1.83 hours with beta-positive emissions and an exemption level of 2.880 MBq 1
• The short half-lives of these radionuclides make decay-in-storage the most practical disposal method 1

Specific Disposal Protocol

For Tc-99m:

• Store waste material for 10 half-lives (approximately 60 hours) 1
• After storage period, less than 0.1% of the original activity remains 1
• Survey the material with appropriate radiation detection equipment to verify activity is below exemption level (0.354 MBq) 1
• If below exemption level, the material can be disposed of as regular medical waste 1

For F-18 FDG:

• Store waste material for 10 half-lives (approximately 18 hours) 1
• After storage period, survey to confirm activity is below exemption level (2.880 MBq) 1
• F-18's shorter half-life offers advantages for waste management and pathological processing of tissue specimens 1
• The higher exemption level for F-18 (compared to Tc-99m) allows for slightly higher residual activity before regular disposal 1

Handling Considerations

• All waste storage areas should be appropriately shielded, secured, and surveyed weekly 1
• For surgical waste containing these radionuclides, superficial contamination must be excluded and exemption levels observed 1
• Semi-conductor germanium detectors can be used for high-precision measurement of specimens to determine if exemption levels are exceeded 1
• Pathologists can generally process tissue specimens the day after surgery, but should verify activity levels are below exemption thresholds 1

Environmental Impact

• Technetium-99m dominates discharges to the environment from excreta of nuclear medicine patients, but its short half-life limits its environmental impact 2
• Storing patient's urine after procedures with these short-lived isotopes appears to have minimal benefit 2
• Radionuclides released into modern sewage systems typically result in doses to workers and the public well below public dose limits 2

Occupational Safety Considerations

• Personnel handling these materials should use appropriate radiation protection measures including gloves, lab coats, and radiation badges 1
• The mean annual Dose Equivalent for nuclear medicine personnel is typically 100-140 mrem (1-1.4 mSv), well below maximum permissible doses 1
• Exposure is generally higher for personnel working with PET isotopes like F-18 compared to those working with Tc-99m 1
• Skin exposure rate from a 50-mL source filled with 1 MBq is 0.56 mSv/h for F-18 and 0.16 mSv/h for Tc-99m 1

Following these guidelines ensures safe disposal of Tc-99m and F-18 FDG radioactive materials while minimizing radiation exposure to staff and environmental impact.