A methodology to evaluate occupational internal exposure to fluorine-18

Area of Science:

• Nuclear medicine
• Radiological protection
• Bioassay techniques

Background:

• Internal monitoring of radioisotopes like Fluorine-18 (18F) is crucial for radiological safety.
• Accurate detection methods are needed to assess potential incorporation of 18F in fluoride and 18F-Fluorodeoxyglucose (18F-FDG) forms.

Purpose of the Study:

• To establish reliable procedures for internal monitoring of 18F.
• To validate both in vivo and in vitro measurement techniques for detecting 18F incorporation.
• To develop a methodology for interpreting bioassay data using established models.

Main Methods:

• Calibration of NaI(Tl) scintillation detectors (8"x4" and 3"x3") for whole-body and phantom measurements.
• Calibration of a High-Purity Germanium (HPGe) detector for in vitro analysis of urine samples.
• Application of International Commission on Radiological Protection (ICRP) models with AIDE software for data interpretation.

Main Results:

• In vivo measurement systems demonstrated sufficient sensitivity for monitoring both fluoride and 18F-FDG.
• In vitro bioassay using HPGe provided accurate quantification of 18F in urine samples.
• Established bioassay interpretation methodology using ICRP models.

Conclusions:

• In vivo measurements are sensitive enough for routine internal monitoring of 18F.
• Combining in vitro and in vivo bioassay data enhances the interpretation of accidental 18F incorporation.
• The developed procedures aid in identifying the specific chemical form of incorporated 18F.