Purpose To establish a new experimental glaucoma model using intracameral injection with various microbeads of different sizes and materials. Methods Chronic elevation of intraocular pressure (IOP) was induced by unilateral microbeads injection into the anterior chamber of Sprague‐Dawley (SD) rats. The effectiveness of different materials (polymethylmethacrylate (PMMA, 7 and 15 µm), polyurethane (PU, 7 and 17 µm), Silica (13 µm)) on IOP elevation was compared. Reinjection of the microbeads was performed at post‐injection day 7. Difference of IOP between both eyes was observed for 4 weeks. Axonal degeneration was assessed by the analysis of light microscopic and transmission electron microscopic photos. Results Total 54 SD rats weighing 250~300g initially were included in this study. After a single injection, the ratio of increased IOPs (mean value) at post‐injection day 3 were 56.6 %, 24.1 %, 23.8 %, 98.1 %, and 153.0 % in PMMA 7 µm, PMMA 15 µm, PU 7 µm, PU 17 µm, and Silica 13 µm, respectively. Since inter‐animal variability of PU 17 µm injected group was smaller than others, so that it was more adequate to produce constant IOP elevation with good repeatability (whereas Silica injected eyes showed severe inflammation). Sustained elevation of IOP by twice of PU 17 µm injection for at least 4 weeks resulted in approximately a 25.5 % loss of axon density (p=0.023, Mann‐Whitney U test). No axonal damage was noted in safety study group. Conclusion These data supports that the polyurethane microbeads injection is an applicable and versatile model for high tension glaucoma in rats. Among several biomaterials, PU showed more stable IOP elevation with safety. Future studies about suitable size and biomaterial of microbeads are more needed to secure this novel model.

Purpose To report the intraocular pressure (IOP) lowering effect of low intensity ultrasound (LIUS) on eyes of ocular hypertensive rats. Methods Continuous radiation of LIUS on ocular hypertensive eyes induced by unilateral microbeads injection was performed. A round plane ultrasound transducer operating at a frequency of 1MHz was utilized to deliver a sonication of 240mW/cm2 in acoustic intensity. LIUS was treated on both eyes of rats (n=5) simultaneously and the IOP measurements of treated group were compared with those of untreated group (n=5). Results The mean IOPs of LIUS‐treated eyes and un‐treated eyes were 9.4 ± 0.55 mmHg and 9.6 ± 0.55 mmHg, respectively at baseline. After an intracameral injection of microbeads, IOPs were reached to 18.6 ± 4.037 mmHg and 22.8 ± 3.493 mmHg (p=0.580) at 3 days after microbeads injection. Then the IOPs were decreased by 39.47 % and 9.68 % at 1 day after a single sonication. Conclusion These results showed that continuous low intensity ultrasound suppresses the IOP elevation in experimental glaucoma model using microbeads injection into anterior chamber. By the reason of its non‐invasiveness and repeatability, LIUS could be an alternative method for glaucoma treatment in near future.

Purpose: To investigate whether pre‐treatment images can be used in predicting microsphere distribution in tumors. When intra‐arterial radioembolization using Y90 microspheres was performed, the microspheres were often delivered non‐uniformly within the tumor, which could lead to an inefficient therapy. Therefore, it is important to estimate the distribution of microspheres. Methods: Early arterial phase CT and FDG PET images were acquired for patients with primary liver cancer prior to radioembolization (RE) using Y90 microspheres. Tumor volume was delineated on CT images and fused with FDG PET images. From each voxel (3.9×3.9×3.3 mm3) in the tumor, the Hounsfield unit (HU) from the CT and SUV values from the FDG PET were harvested. We binned both HU and SUV into 11 bins and then calculated a normalized joint‐histogram in an 11×11 array.Patients also underwent a post‐treatment Y90 PET imaging. Radiation dose for the tumor was estimated using convolution of the Y90 distribution with a dose‐point kernel. We also calculated a fraction of the tumor volume that received a radiation dose great than 100Gy. Results: Averaged over 40 patients, 55% of tumor volume received a dose greater than 100Gy (range : 1.1 – 100%). The width of the joint histogram was narrower for patients with a high dose. For patients with a low dose, the width was wider and a larger fraction of tumor volume had low HU. Conclusion: We have shown the pattern of joint histogram of the HU and SUV depends on delivered dose. The patterns can predict the efficacy of uniform intra‐arterial delivery of Y90 microspheres.