Effect of Thyroid Blockade on Net Thyroid ROI Counts on Early and Late (Decay-Corrected) 123I-mIBG Imaging
| Parameter | Subjects (n) | Mean early thyroid counts | Mean late thyroid counts | Mean net count change (%) | No. with increased (late vs. early) thyroid counts (%) | No. with decreased or unchanged (late vs. early) thyroid counts (%) |
| Nonblocked | 227 | 7,997 (SD, 6,927) | 13,864 (SD, 10,423) | +5,867 (73.4%) | 171 (75%) | 56 (25%) |
| Blocked | 442 | 9,033 (SD, 8,855) | 5,440 (SD, 6,021) | −3,593 (−39%) | 59 (13%) | 383 (87%) |
| P | 0.11 | <0.0001 | <0.0001 |
Early = 15 min after administration; late = 3 h 50 min after administration.