Significance of radiocontaminants in 123I for dosimetry and scintillation camera imaging

Estimates of absorbed radiation dose and qualitative assessments of image resolution were compared for pure 131I and for 123I produced by the 122Te(d,n), 124Te(p,2n), and 127I(p,5n) 123Xe reactions. A substantial reduction in radiation dose is indicated when 123I replaces 131I, in spite of the radiocontaminants typically present 30-35 hr after the production of 123I by any of these methods. Only a marginal further reduction in radiation dose was noted with use of the most "pure" 123I as opposed to the least "pure" 123I. Comparable scintillation camera resolution was obtained for all 123I preparations at 30-35 hr after bombardment when the medium-energy and pinhole collimators were used. However, the radiocontaminants in the 123I produced from tellurium affected image resolution when the low-energy collimator was used.