On the right side of the radiograph viewer window, beneath the slider, is a list of all possible detections.
By clicking the checkboxes next to each detection listing, you can show or high that detection type or the entire class of detection (pathology/non-pathology) within the radiograph display.
If a detection type is greyed out, no detections of that type appear in the radiograph.
Clicking on a detection type will expand the list to show you all detections of that type. If you hover you mouse over one of the detections in the expanded list, you will see that specific detection highlighted in the on radiograph in the display.
Just to recap, here's an overview of how to use the Detections Controls: