New filter for iodine applied in nuclear medicine services

Area of Science:

• Nuclear Medicine
• Radiological Safety
• Environmental Engineering

Background:

• Radioactive iodine (radioiodine) is crucial in nuclear medicine for diagnostics and therapy.
• High doses of radioiodine (3.7–7.4 GBq/patient) necessitate measures to mitigate occupational contamination risks.
• Existing exhaust systems require effective filtration to handle radioiodine safely.

Purpose of the Study:

• To develop and evaluate a low-cost, domestic-technology filter for capturing radioiodine.
• To reduce the risk of occupational contamination for medical professionals handling radioiodine.
• To ensure radiological safety requirements are met in exhaust systems.

Main Methods:

• Radiotracer techniques were used to verify the effectiveness of silver-impregnated silica (SiO2+Ag) and natural activated carbon.
• The filter was designed as a double-stage system with SiO2+Ag followed by activated carbon.
• Filter performance was assessed for an exhaust flow rate of (145 ± 2) m³/h.

Main Results:

• Both SiO2+Ag and activated carbon demonstrated effectiveness in capturing iodine (I2).
• Activated carbon is restricted due to its low flash point (423 K), which can be further lowered by solvents, posing explosion risks.
• SiO2+Ag did not effectively capture methyl iodide (CH3I), necessitating activated carbon for this specific gas.
• A double-stage filter (SiO2+Ag then activated carbon) met radiological safety requirements.

Conclusions:

• A dual-stage filter comprising silver-impregnated silica followed by natural activated carbon is effective for radioiodine capture.
• This filter design provides a cost-effective solution for enhancing radiological safety in nuclear medicine exhaust systems.
• The system is sufficient for exhaust flow rates around 145 m³/h, significantly reducing occupational exposure risks.