how to erode small shapes

Hi,

i am trying to erode a small shape, since it's a region on an MR images i can't find the suitble struct element disk doesn't work since the object is very small square doesn't give a good result

thanks in advance

[Image Analyst]

So you want us to give advice on how to process your image without even seeing your image???

[sbei arafet]

Sorry for not uploading it here is the image i want to erode the red shape