ImageJ plugin for assessing HER2 immunohistochemistry, described in [bib]2472[/bib]. It is important to read the URL documentation and original paper to understand how to use the plugin appropriately. Note also that the *pixel size* is not read automatically from the image, but rather the *source image scale* should be entered into the dialog box - and the image rescaled accordingly prior to analysis. This scale value is the *inverse* of the value normally found for *pixel width* and *pixel height* under *Image -> Properties...* (i.e. pixel width & height are given in microns per pixel; the dialog box asks for pixels per micron).