['The aim of this study was to investigate the safety and efficacy of intravitreal injection of (99)Tc-MDP, a decay product of (99m)Tc-MDP, on the development of laser-induced choroidal neovascularization (CNV) in rhesus monkeys.', 'Experimental CNV was induced by argon laser with a small high-energy laser spot. Monkeys were given 50 μL of (99)Tc-MDP at a concentration of 0.005 μg/mL (n\u2009=\u20096) or 0.01 μg/mL (n\u2009=\u20096) by intravitreal injection once a week immediately after laser injury for a period of 56 days. Control animals were treated with the same volume of PBS (n\u2009=\u20096) in the same way. Eyes were monitored by ophthalmic examination, color fundus photography, fluorescence fundus angiography (FFA), optical coherence tomography (OCT) and histology. Incidences of grade 4 CNV lesions as well as the leakage areas of grade 4 CNVs on the late-phase of fluorescein angiograms were measured in a standardized, randomized and masked fashion fortnightly. The maximum widths and heights of grade 4 CNVs were also calculated by histology at the end of the experiment. Toxicity of (99)Tc-MDP on the retina was evaluated by electroretinogram (ERG) and histologic analysis.', '(99)Tc-MDP reduced the incidences of grade 4 CNVs by 33.33 % and 39.40 % in the 0.005 μg/mL and 0.01 μg/mL groups, respectively, compared with the PBS group on day 28 (P\u2009<\u20090.05; n\u2009=\u20096). The leakage areas of grade 4 CNVs were smaller in the 0.005 μg/mL (0.7136\u2009±\u20090.0283 mm(2), p <0.01; n\u2009=\u20096) and 0.01 μg/mL (0.4351\u2009±\u20090.0349 mm(2), p\u2009<\u20090.01; n\u2009=\u20096) groups than those in the PBS control group (0.9373\u2009±\u20090.0455 mm(2); n\u2009=\u20096) in a dose-dependent manner on day 28. OCT and histology also showed that the sizes of CNVs were smaller in the (99)Tc-MDP treated groups than those in the PBS group. Although intravitreal injection of (99)Tc-MDP led to mild inflammatory reaction in the anterior chamber, histology and ERG findings demonstrated that (99)Tc-MDP did not cause any change in histological structure or function of the retina (p>0.05).'] Does intravitreal injection of ( 99 ) Tc-MDP inhibit the development of laser-induced choroidal neovascularization in rhesus monkeys?