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This work uses Monte Carlo radiation transport simulation to assess the potential benefits of gold nanoparticles (AuNP) in the treatment of Neovascular Age-Related Macular Degeneration (AMD) with stereotactic radiosurgery. Clinically, a 100 kVp X-ray beam of 4 mm diameter is aimed at the macula to deliver an ablative dose in a single fraction. In the transport model, AuNP accumulated at the bottom of the macula are targeted with a source representative of the clinical beam in order to provide enhanced dose to the diseased macular endothelial cells. It is observed that, because of the AuNP, the dose to the endothelial cells can be significantly enhanced, allowing for greater sparing of optic nerve, retina and other neighboring healthy tissue. For 20 nm diameter AuNP concentration of 32 mg/g, which has been shown to be achievable in vivo, a dose enhancement ratio (DER) of 1.97 was found to be possible, which could potentially be increased through appropriate optimization of beam quality and/or AuNP targeting. A significant enhancement in dose is seen in the vicinity of the AuNP layer within 30 um, peaked at the AuNP-tissue interface. Different angular tilting of the 4 mm-beam results in a similar enhancement. The DER inside and in the penumbra of the 4 mm irradiation-field are almost the same while the actual delivered dose is more than one order of magnitude lower outside the field leading to normal tissue sparing. The prescribed dose to macular endothelial cells can be delivered using almost half of the radiation allowing reduction of dose to the neighboring organs such as retina/optic nerve by 49% when compared to a treatment without AuNP.

Empirical collections of retinal images gathered over the years form the basis of many retinal interventions. Identification of the diseased retina requires understanding of abnormal patterns and colors in the retina. Quantification of the clinician's interpretation of pathological changes in morphology and color is the subject of this presentation. In particular, various hyperspectral imaging techniques which map wavelength-resolved reflectivity across a two dimensional scene offer considerable promise as a new clinical tool. Quantification of retinal images could permit both early detection as well as monitoring of the effectiveness of therapy.Because the delicate nature of the eye usually precludes invasive biopsy or mechanical access to the retina, current diagnosis of retinal disease relies strongly upon optical imaging methods. Not coincidentally, the photon sensing role of the eye implies optical access to the retina over a wide band of wavelengths. A variety of lens systems exist that take advantage of the optical transparency of ocular media in order to image the retina in vivo. When imaged, the normal retina presents an overall reddish appearance because the globally present chromophores hemoglobin and melanin absorb more strongly at shorter wavelengths. The local concentrations of hemoglobin delineate parts of the complex network of blood vessels in the retina. In an abnormal retina, local changes in physiology can vary the balance of chromophores, altering the local reflectivity spectrum. Examples include the presence of large concentrations of hemoglobin as a result of hemorrhage in vascular diseases such as diabetic retinopathy, or the presence of abnormal protein or lipid concentrations in diseases such as macular degeneration.with transparent gel. Imaging onto the curved retina is accomplished primarily by the curved air-cornea interface. A contractile pupil defines the optical throughput. The cornea and lens image light onto the curved retina. The retina itself is less than a millimeter thick. Normally, it is essentially transparent, with the exceptions of hemoglobin and a layer containing melanin, both strong optical absorbers. The choroid, an optically dense complex of blood vessels, lies between the retina and the sclera. The sclera, a highly scattering medium, not only forms the mechanical structure of the eye (the "white"), but is responsible for much of the backscattering that enables retinal imaging. Retinal diseases can occur either above the melanin layer or below it.We will discuss hyperspectral imaging methods using external illumination from a filtered tungsten lamp, projected in non-imaging mode by a standard ophthalmic fundus camera. This device also enables convenient image relay from the retina to a hyperspectral imaging system. Light gathered by the fbndus camera originates from backscattering caused by the retina, choroid, and sclera. Both wavelength-dependent scattering and wavelength-dependent absorption determine the spectrum of light emerging from an area element of the reti...

Stereotactic radiotherapy in the induction phase of intravitreal injections of ranibizumab for treatment naïve patients with neovascular age-related macular degeneration, resulted in improved visual outcome, statistically fewer injections and statistically drier macular at 12 months, compared to historical controls treated with monotherapy intravitreal ranibizumab injections.