The use of ocular plaques is a promising treatment option for eye melanoma brachytherapy. Although several studies have been done on various ocular plaques, little is known about the dose characterization of Au plaque.
The full mathematical model of the eye phantom, tumor, Ru/Rh CCA, and Au plaque were simulated using the Monte Carlo MCNPX code. The dose distribution was measured in the plaque’s central axis direction, and a dose profile was also measured at a distance of 2.5 mm from the plaque surface.
The findings showed that Au plaque has superior dosimetric characteristics than CCA plaque for tumors with a thickness of greater than 3.5 mm, while CCA plaque is better for tumors with a thickness of less than 3.5 mm. The dose to the sclera and choroid is higher in the case of CCA plaque, while the dose to the organs at risk (lens and optic nerve) is greater in the case of Au applicator. In the case of Au plaque, however, the dose to sensitive organs was within their permissible dose range.
In the treatment of medium and large tumors, Au plaque is more successful than CCA plaque. It can produce a much more homogeneous lateral dose profile in the target. In the treatment of dome-shaped tumors, Au plaque may be more successful than CCA plaque. As a result, the tumor’s shape influences the plaque type selection.

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