123

 

 

 

Radiation

Electrons – 3 keV (94%); 23 keV (12%); 127 keV (14%); others (<2%)

Gamma & X-ray – 159 keV (83%); 27 keV (70%); 31 keV (16%); others (< 10%)

 

 

Half-Life [T1/2] 

Physical [T1/2]: 13.2 hours

Biological [T1/2]: 120-138 days (unbound iodine)

Effective [T1/2]: ~ 12 hours (unbound iodine)

 

 

Decay 

Iodine-123 is a pure gamma emitter and has excellent characteristics for imaging with modern scintillation cameras. Iodine 123 disintegrates by electron capture mainly via 159 keV level of Te-123 (97%)

 

 

Specific Activity:

1.93E6 Ci/g [7.14E16 Bq/g] max.b

 

 

Critical Organ:

Thyroid Gland

 

Intake Routes:

Ingestion, inhalation, puncture, wound, skin contamination (absorption)

 

 

Shielding:

Lead [Pb] 1 mm (0.04 inches) Half Value Layer [HVL]

 

 

Monitor:

Conduct a baseline thyroid scan prior to first use of radioactive iodine.

 

 

 

*Please see P & D for production and disposal of 123-Iodine*