Abstract: Objective To explore the application of orbital 99mTc labeled octreotide SPECT/CT on the treatment effect evaluation of active thyroid associated ophthalmopathy(TAO). Design Retrospetive case series. Participants Twenty-one patients with active TAO were observed, with 37 afflicted eyes and 5 normal eyes. Methods Orbital 99mTc labeled octreotide SPECT/ CT and the clinical activity score (CAS) were separately performed before and after treatments in the patients with TAO. Main Outcome Measures An uptake ratio between the orbits and the occipital skull（O/OCC）, the numbers of involved extraocular muscles（N） and CAS. Results Before treatment,the average of N was 2.70±1.00 and its CAS was (5.49±2.04). Before treatments, the O/OCC of afflicted eyes(2.00±0.35) were higher than that in normal eyes(1.14±0.10)(P=0.000). After treatments, the O/OCC, CAS and N were (1.38±0.30), (1.78±1.18), (1.16±0.93) on average, respectively and significantly reduced compared to those before treatment in afflicted eyes（all P=0.000）. There was no statistical differences in normal eyes before and after treatments in the O/OCC(1.03±0.07) (P=0.242). A statistically significant correlation was found in the O/OCC versus CAS before and after treatments (r=0.574，P<0.01; r=0.555，P<0.01). A statistically significant correlation was also found in N versus CAS before treatments (r=0.445，P<0.01), but not found after treatments (r=0.235，P>0.01). Conclusion Orbital ^99mTc labeled octreotide SPECT/ CT is with good prospect in evaluating treatment effect of active TAO. (Ophthalmol CHN, 2013, 22: 309-312)

Key words: thyroid associated ophthalmopathy, technetium, radionuclide imaging, octreotide